Asteraceae are the largest family of dicotyledonous plants. It contains from 1150 to 1300 genera and more than 20,000 species. Asteraceae are found almost everywhere where the existence of higher plants is generally possible - from the tundra to the equator, from sea coasts to alpine snows, on barren sands and on rich black soils.
Plants of this family are usually easy to distinguish from representatives of other families by their characteristic inflorescence - the basket. The base of the basket is formed by an expanded bed of the inflorescence, or a common receptacle (Fig. 245), on which flowers closely adjacent to each other are located. Outside, the common receptacle is surrounded by an involucre consisting of more or less strongly modified upper leaves. The main function of the wrapper is to protect the flowers from adverse external environmental influences. The leaflets (or leaflets) of the involucre are arranged in one, two or several rows. The sizes of baskets in wild asteraceae are most often small - with a diameter ranging from one to several centimeters. Only occasionally the baskets are larger - up to 10-15 cm in diameter, and in the cultivated annual sunflower (Helianthus annuus) they reach the size of a large dish in diameter - up to 60 cm. At the same time, many wormwood baskets are tiny - only 2 in height and width -4 mm. The general receptacle can be more or less flat (as, for example, in a sunflower), but can also be concave, convex, cone-shaped or of other shapes.
The flowers of Asteraceae are usually small. The calyx is modified into a pappus (sometimes also called a fly or pappus). The pappus consists of a more or less significant number of different types of bristles, hairs, awns, or it is represented only by a membranous rim (crown). Sometimes the tuft disappears completely, and then the flower is completely devoid of a calyx. In more primitive Asteraceae, scales are clearly visible - the rudiments of a lobed calyx. The corolla is fused-petalled. Its shape varies greatly. It is more or less actinomorphic, in which case it is tubular; if the corolla is zygomorphic, then it is most often either ligulate or so-called bilabial. There are many transitional forms between these basic forms.
The stamens, usually 5 in number, are attached to the corolla tube. The filaments of the stamens are free, and the anthers stick together with their sides, forming an anther tube through which the style passes. The anthers are mostly elongated, longitudinally dehiscent, introsular. Rarely, for example, in the genus Ambrosia, the anthers are free, and the filaments of the stamens are fused. The gynoecium consists of 2 carpels with a style that ends in 2 stigmatic lobes or branches; in sterile flowers the style is sometimes undivided. In fertile flowers, the lobes of the style protrude from the corolla and often diverge greatly. WITH inside The stigma blades are equipped with a special receptive (stigma) tissue. Many species of the family are characterized by the presence of so-called collecting or sweeping hairs, which help remove pollen from the anther tube. The location of these hairs (in the form of a collar under the stigmatic lobes or over a more or less significant extent outside blades), their density and length are very diverse. The ovary is inferior, unilocular, at the base with one ovule (very rarely there are two), located on a short placenta (funiculus). In mature seeds, there is no endosperm or only traces of it are found.
The fruit of Asteraceae is an achene. This is a single-seeded, indehiscent fruit with a more or less dense, leathery and usually thin pericarp, usually separated from the seed. Only in very rare cases, as in species of the neotropical genus Wulfia, are achenes with a succulent pericarp.
Brief information about the flower and associated structures, which were described above, refer to the well-developed bisexual flower of the Asteraceae. However, not all species of this family have all the flowers in the basket bisexual and fertile. Often there are 2 more types of unisexual flowers - female (usually fertile) and male (sterile), as well as sterile flowers in which both the androecium and gynoecium are reduced. The basket can be uniformly flowered (homogamous), but more often heterogeneous (heterogamous). In this case, the center of the basket is occupied by bisexual tubular flowers, and female and often brightly colored reed flowers radiate along the periphery. In a heterogamous basket, other combinations of flowers are observed, different in structure and sex.
The leaves are mostly alternate. Size, shape and degree of dismemberment leaf blade vary greatly, from very large, like the Japanese butterbur (Petasites japonicus), growing on Sakhalin, the Kuril Islands and Japan (the plate of its entire basal kidney-shaped leaf reaches 1.5 m in diameter, and the petiole is 2 m long), to small , very reduced, like the American leafless baccharis (Baccharis aphylla) with twig-like photosynthetic stems. The leaves of some American vines from the genus Mutisia (Mutisia, Fig. 247) are very original. In most Asteraceae, the leaves are characterized by one or another type of pinnate venation. However, there are leaves with strictly parallel or parallel-arcuate venation, as in some species of the genus Scorzonera.
Many Asteraceae are characterized by pubescence. The hairs of Asteraceae are very diverse: single- or multicellular, hard and soft, straight and tortuous, simple (unbranched) or bifid, star-shaped. Dense pubescence is especially often well expressed in species living in conditions of constant dryness or sudden changes in temperature. Thus, growing in Central Asia, cotton wool (Lachnophyllum gossypinum) in its young state is covered, like cotton wool, with soft tangled hairs. Talking about aboveground parts, we should also mention the noticeable percentage of thorny plants among the Asteraceae. The leaves and stems are prickly.
The vast majority of species of the family have a developed tap root. Often the root is tuberously thickened, which, for example, is typical for burdocks (species of the genus Arctium). Many species of the family develop contractile (retracting) roots; in plants with a basal rosette, they often ensure that the rosettes adhere tightly to the ground. In subshrub and subshrub Asteraceae, the taproot is usually woody and well developed. In addition, they form the so-called caudex or stem root - a perennial formation, mainly of shoot origin. The caudex carries renewal buds and often serves as a site for the deposition of reserve nutrients. The beautiful tree plant (Fitchia speciosa), growing on the island of Rarotonga (Cook Islands), has well-defined aerial supporting roots. Endomycorrhiza has been found in many Asteraceae.
Most Asteraceae are herbs, either perennial or annual, that range in size from very large, like some sunflowers, to tiny. But among them there are also many subshrubs and shrubs. Shrubs - from 1 to 5 m and only sometimes higher (up to 8 m). Trees, usually low, are also found among the Compositae. Many tree forms are characteristic of oceanic islands. As part of the genus Scalesia, endemic to the Galapagos Islands, species are known with trunks reaching a height of more than 20 m with a diameter of 25-30 cm, such as S. pedunculata. They form real forests. Charles Darwin mentions them in his famous “Diary of Research in Natural History and Geology...” (better known to Russian readers under the title “A Voyage Around the World on the Beagle Ship”). Dioecious plants grow in South Africa and Madagascar woody plants from the genus Brachylaena, and among them is a tree of the first size endemic to Madagascar - Brachylaena merana. It reaches a height of 40 m and a diameter of up to 1 m; Its wood is resistant to rotting and is highly valued.
Among the tree-like Asteraceae there are so-called rosette trees. Their trunk does not branch or weakly branches and bears a crown of leaves at the top like a bunch or rosette. Rosette trees from the genus Senecio reach a height of 7.5 m. They are characteristic of the landscapes of the highlands of the African tropics. Many Asteraceae are cushion-shaped. Thus, Haastia pulvinaris, growing in the subalpine and alpine zones of New Zealand, forms pillows with a diameter of over 2 m and a height of 60 cm. Haastia, together with another cushion-shaped asteraceae - Raoulia eximia - due to its light, dense pubescence, stands out well among the stones.
Lianas are rare among Asteraceae. Large vines are known in the genera Vernonia, Mikania, Mutisia, Fig. 247 and a few others. All of them are inhabitants of warm countries.
Among the Asteraceae there are many leaf and stem succulents; many of them are found in garden-greenhouse culture. The largest number of succulent asteraceae live on the southern tip of Africa and further northeast to Ethiopia, as well as in Madagascar.
Aquatic plants are rare among the Asteraceae. The most famous are the North American Sclerolepis uniflora and two species of the genus Bidens. The original aquatic Mexican species are water pectis (Pectis aquatica) with a floating stem about 30 cm long and semi-submerged small-petalled heteromorphic (Erigeron heteromorphus), the upper leaves of which are entire or serrated, and those immersed in water are hair-like. An aquatic plant with opposite, thinly dissected leaves, Cotula myriophylloides grows in South Africa.
In some Asteraceae, the stems are modified in phylloclady and take on the function of photosynthesis. This is observed, in particular, in several American species of the genus Baccharis, for example in Baccharis articulata.
Like representatives of the order Campanaceae, the main storage carbohydrate in Asteraceae is inulin (and not starch, as in most other dicotyledons).
Many Compositae belong to plants with a high degree of sensitivity to light, which is expressed in the ability to open and close the baskets depending on the intensity of light. Often this sensitivity is so pronounced that it is easy to observe without resorting to any instruments. That is why among the flower clocks that were proposed in the first half of the 18th century. K. Linnaeus, Asteraceae are especially abundant. Flower clock - a set of plants planted in a small area, the flowers of which are clear sunny days open and close at certain times. The accuracy of such watches is from half an hour to an hour. For each area, the set of plants should be different, previously established by observations.
Among the Asteraceae there are so-called compass plants. At midday, they are able to position their leaves with their edges facing the light falling on them; in this case, one wide side of the plate faces east, and the other faces west. This arrangement of leaves protects against overheating by the sun's rays and helps reduce transpiration, without reducing the intensity of photosynthesis. Compass plants are usually inhabitants open places. Among such plants, the wild or compass lettuce (Lactuca serriola), widespread in Eurasia, and the North American lobed silphium (Silphium laciniatum) are well known. At a time when the vast expanses of the American prairies were still poorly developed, the position of silphium leaves replaced a compass for lost hunters.
The responsiveness of some Asteraceae not only to light, but also to air humidity and other atmospheric phenomena has long been noted in the community. Therefore, species of this family serve as a kind of barometer. So, if the basket of the sow thistle opens on a more or less clear day, then rain is very likely the next day. The literature also contains data on longer-term “predictors” of weather among Asteraceae; it is indicated, for example, that the formation of a rosette of leaves in Helenium autumnale is associated with the nature of the upcoming winter.
The vast majority of Asteraceae are insect-pollinated plants. Early spring species temperate regions often have golden or orange-yellow flowers in a basket, which stand out well on dark soil that is still lightly covered with other plants. In many Asteraceae, the inconspicuous tubular flowers of the basket are surrounded on the periphery by bright white, yellow or red large flowers, which are clearly visible from a great distance. These peripheral flowers are often sterile and perform no other function other than signaling. Insect-pollinated Asteraceae with small baskets, hardly noticeable individually, have more or less large, clearly visible common inflorescences.
Insects visiting Asteraceae are attracted by nectar, usually secreted at the base of the style, as well as pollen. The main pollinators are bees, wasps, bumblebees and other Hymenoptera, as well as Lepidoptera. More rare pollinators are hoverflies (syrphids) and other dipterans, as well as beetles and representatives of other orders of the insect class. Often the same Compositae is visited not by one or two, but a large number various types of insects. There is evidence that some species of the genus Mutisia are pollinated by birds.
Most Asteraceae exhibit protandry. Just like in bellflowers, the anthers open while still in the bud and the pollen ends up inside the anther tube even before the flowers open; at this male phase of flower development, the style is still short and the lobes or branches of the stigma are still tightly closed; by the time the flower opens, the column lengthens and gradually, like a piston in a cylinder, pushes out pollen, as we have already seen in representatives of the lobeliaceae subfamily of the bellflower family.
Of the features that ensure the success and accuracy of cross-pollination, of great interest is the peculiar pollen-feeding mechanism observed in quite a few Asteraceae, for example, in species of the genus cornflower (Centaurea, Fig. 248). They have sensitive filaments of stamens that have the ability to contract. As a result, when insects touch the stamens, the anther tube moves down, and the column with sweeping hairs located underneath carries out pollen, which falls on the insect. Many Asteraceae have adaptations that ensure pollination between different flowers within one basket.
In cases where cross-pollination for some reason does not occur, self-pollination usually takes place. It is ensured by the ability of the stigmatic lobes of the style to twist so that they come into contact with their own pollen.
In relatively few Asteraceae, for example in species of the genus cocklebur (Xanthium, see Fig. 246), protogyny is observed. Anemophilia is common. It is considered as a secondary phenomenon and is characteristic of plants of wide open spaces, for example, species of wormwood (Artemisia); their baskets, as a rule, are small, inconspicuous, collected in complex common inflorescences.
Some Asteraceae have cleistogamous flowers.
In addition to the normal sexual process, apomixis is often observed in Asteraceae, especially among representatives of the lettuce subfamily, for example in the genus Dandelion (Taraxacum).
The number of fruits is very significant, and in many cases extremely large. The fruits are usually small and weigh negligibly. The length of the achenes often does not exceed 5 mm and the width is 1 mm. The largest fruits are found in the above-mentioned arboreal plant; they reach a length of 5 cm. Very often, achenes are equipped with hairs, bristles, papillae, and so on, and in some anthemideas (tribe Anthemideae), the achenes are covered on the outside with special mucilaginous cells, which apparently contribute to the germination of the primordia in dry conditions.
Among the Asteraceae there are many anemochores. Of primary importance for this is the tuft, located directly at the top of the achene or raised on an extended narrow tip - the spout. Usually the crest consists of of various structures hairs or bristles, which are hygroscopic and can act as a flying machine only in dry weather. The crest belongs to the most perfect adaptations of this genus in the plant world; its position - above the center of gravity - is especially successful when the crest is on the nose. In general, the crest-parachute of Asteraceae, as shown by special studies, is, as it were, calculated according to the exact laws of aerodynamics; it gives the achenes significant stability in flight and increases the dynamic lifting force acting on the achenes. The crests of Asteraceae with feathery hairs are especially perfect. Here it is appropriate to recall that the first printed work of the remarkable Russian botanist V.I. Taliev, published by him in Kazan in 1894, is devoted to a detailed study of the mechanism of movement of the hygroscopic hairs of the tuft. Lecocarpus pinnatifidus, a shrub endemic to the Galapagos Islands, has a flying apparatus made of a covering leaf.
Very small and light achenes of Asteraceae, such as those of wormwood, although they do not have a special aircraft, are also partially carried by the wind.
In Asteraceae, which grow near water, the primordia are often carried by water, for example, in some species of butterbur (Petasites), string (Bidens), etc. In Chorisis repens, which grows in the USSR on Far East on the sands and pebbles of sea coasts and at the mouths of large rivers, the achenes have a thickened porous shell - an adaptation to their distribution by water.
Among the Compositae there are many zoochoric species. In the desert ephemeral Koelpinia linearis, the achenes are seated on the back with hooked spines and, in addition, end at the end with a bunch of the same spines collected in the form of an anchor. Thanks to this, Kelpinia fruits stick to animal fur and human clothing. In burdocks, when the achenes ripen, entire fruit baskets easily break off from the plants and, thanks to the tenacious leaves, the wrappers stick to the hair of animals and people’s clothing. For a relatively small number of species, the phenomenon of myrmecochory was also noted. The fruits of some Asteraceae are dispersed when their elastic stems or peduncles are swayed. These are the so-called ballista plants. Their achenes are completely without a tuft or have tufts of coarse hairs, and sometimes are too short to be suitable for dispersal by the wind.
There are achenes that can crawl some distance from the mother plant, as, for example, in blue cornflower (Centaurea cyanus) and common cornflower (Crupina vulgaris). The pappus of these plants is too small for anemochory. But thanks to the hygroscopic movements of the bristles of the pappus, falling down during rain and spreading out in dry weather, the achene is able to crawl.
Among the Compositae there are also representatives belonging to the tumbleweed life form. They are characteristic of plants living in open (treeless) spaces, for example in the steppes. An example of them is the spreading cornflower (C. diffusa), which in the USSR grows in open places, mainly in the south of the European part and in the Caucasus. Another example is the dwarf asteriscus (Asteriscus pygmaeus). It is an annual plant distributed from the Sahara to Balochistan and has hygroscopic involucre leaves. After the achenes ripen, these leaves close, and the plant can remain in this state for 8-10 months. The dispersal of achenes, associated with the opening of the involucre, occurs in wet weather, which contributes to their successful germination.
In the last few centuries, when communication and transportation various cargoes between continents and countries became intense, the exceptional fertility of some Asteraceae, combined with their unpretentiousness, allowed them to develop vast new spaces, many times larger than the original (natural) range. An example is the North American conyza (Conyza canadensis), which first appeared in Europe only in the 17th century. and now has become a cosmopolitan. There are also well-known cases when European Asteraceae, having arrived on other continents, began to displace the aborigines there. Thus, drooping thistle (Carduus nutans), brought to North America from Europe at the end of the last century, it has now become a widespread and difficult to eradicate weed there.
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From biological features In the achenes of the Asteraceae, let us also mention the heterocarpy, or heterocarpy, observed in many species of this family. Heterocarpy is well expressed in the officinalis calendula (Calendula officinalis, Fig. 249, table 64), widely known for the shape of its curved achenes called “marigolds”. In one basket of calendula there are claw-shaped, navicular and ring-shaped achenes, as well as transitional forms between them.
The Asteraceae family is divided into 2 subfamilies: Asteraceae (Asteroideae), which unites the vast majority of genera of the family and includes 11-12 tribes, and a more homogeneous subfamily of Lettuceae (Lactucoideae), or Chicoryaceae (Cicliorioideae), which includes only one tribe. We have the opportunity to touch only on some of the most important tribes.
Forest herbaceous plants
Asteraceae Image of 12 inflorescences of Asteraceae Scientific classification Kingdom: Plants Division: Angiosperms ... Wikipedia
- (Asteraceae, or Compositae) family of dicotyledonous plants; includes about 25 thousand (according to other sources, 13-20 thousand) species (900-1000 genera), distributed throughout to the globe and presented in all climatic zones. Most S.... ...
Asteraceae, order (Asterales) of dicotyledonous plants and units, family (Asteraceae, or Compositae) of this order. Herbs, less often subshrubs, shrubs, tree-like forms (so-called rosette trees) and trees (in the tropics). Inflorescence basket,... ... Biological encyclopedic dictionary
GOLDENROAD OR GOLDEN ROD (SOLIDAGO VIRGAUREA L.)- see Perennial with oblique, short rhizome and straight, bare or pubescent stems, 20-80 cm high. With winged petiole, ovate or spatulate; stem leaves petiolate or upper sessile, oblong or lanceolate, acute, ... ... Forest herbaceous plants
MYCELIS MURALIS (L.) DUMORT.- see. Perennial or biennial with a short vertical rhizome and single bare stems, branched at the top, 30-120 cm high. The lower ones are rosette-shaped, with long winged petioles, lyre-shaped and pinnately dissected, with... ... Forest herbaceous plants
TsMIN, OR SANDY IMMORTELLA (HELICHRYSUM ARENARIUM (L.) MOENCH)- see Turfy, tomentose perennial, with shortened vegetative and elongated generative shoots. The stems are 15–40 cm high, unbranched, straight, with remnants of dead leaves on the rhizome. The lower leaves are petiolate, linear... ... Forest herbaceous plants
KITAMURA, OR KOMAROV'S UNDERripening (CACALIA KITAMURAE NAKAI (C. KOMAROVIANA (POJARK.) POJARK.)- see. Perennial with a creeping rhizome and a stem 1-2 m high, furrowed and pubescent at the top with glandular hairs. The leaves are large, 20-35 cm long. They are spear-shaped, their lateral lobes are double-cut, with long pointed lobes of the second... ... Forest herbaceous plants
Image of 12 aster inflorescences ... Wikipedia
Angiosperms (Magnoliophyta, or Angiospermae), a division of higher plants that have flowers. There are over 400 families, more than 12,000 genera and probably at least 235,000 species. According to the number of species of C. r. significantly superior to all others... Great Soviet Encyclopedia
Main hallmark This family is that, as the name itself shows, its flowers are complex, that is, what is commonly called a flower is actually a whole inflorescence of small flowers. These flowers sit on a common bed, that is, the extended end of a peduncle, which has a flat, concave or convex surface and is surrounded by a common involucre, a common calyx, consisting of one or more rows bracts(small leaves located on a peduncle) - it turns out something like a basket. Individual flowers are usually very small, sometimes very small, only 2-3 mm long. They consist of an inferior ovary, unilocular and single-seeded, at the top of which is attached a petaled corolla. At its base there is usually a row of hairs or bristles, several denticles or a membranous border. These formations correspond to a rudimentary calyx.
The corolla is fused-petalled, varies greatly in shape, but there are two most common types: tubular, with a regular five-tooth bend, and an irregular one, the so-called reed, and all five of its lobes grow together into one plate, bent in one direction. All Asteraceae, with rare exceptions, have five stamens; they grow with their filaments to the corolla tube, and with their anthers they grow together into one hollow tube surrounding the style, which ends in a bipartite stigma different devices.
In many plants of the described family, the heads consist only of tubular flowers, such as cornflowers, burdock, thistle, and artichoke. Others, like dandelion, goatweed (scorzonera), lettuce, chicory, etc., have all ligulate flowers. Finally, still others have both types of flowers in each head: reed-shaped around the circumference, and tubular in the center (for example, sunflower, aster, dahlia, marigold, marigold, chamomile).
We can also mention the third type of corolla - bilabiate, in which three lobes of the corolla are directed in one direction, and the remaining two in the other.
The size of the inflorescence is usually small, up to several centimeters in diameter; and only in some species it reaches a diameter of 10-15 cm, and in cultivated sunflower, which has the largest inflorescence in the family, it can reach up to 60 cm. At the same time, in some types of wormwood, the height and width of the inflorescence does not exceed 2-4 mm .
Leaves
Pollination
Spreading marigolds ( Tagetes patula)
Spreading
Asteraceae are distributed throughout the globe, but they play a particularly important role in North America. They also live in significant numbers in Central Asia and throughout southern Europe, but towards the north the number of their species decreases significantly.
Application
As a food product
Like flowers
Paints
Weeds
Among the dangerous weeds we can distinguish plants from the genus Ambrosia ( Ambrosia), causing allergic hay fever. Ambrosia comes from America, but has spread very widely throughout the world, including in Russia - 5 species out of 30. Galinsoga parviflora can also be classified as a weed. Galinsoga parviflora), some types of sequence ( Bidens) and etc.
Classification
The Asteraceae family includes two subfamilies - Asteraceae (subfamily) ( Asteroidae) and Lettuce, or Chicory, or Molocanaceae ( Lactucoideae, or Cichorioideae ) .
In the literature, other names for these subfamilies are sometimes found - respectively Tubeflowers(lat. Tubuliflorae) And Reed(lat. Liguliflorae). This name for the subfamily Asteraceae is due to the fact that its representatives have mostly tubular flowers, and only marginal flowers are ligulate. Representatives of the Lettuce subfamily always have ligulate flowers.
No matter how much we say that we don’t compete with our neighbors, we still want our flowerbed to be at least as good. If it's worse, something needs to be changed. When reconstructing a flower garden, it is easiest to rely on plants from the Asteraceae family (aster is Latin for star). Below we will talk about some representatives of this botanical community, and you decide for yourself what color spot to create under your windows - purple, yellow, blue or something else. At the same time, we’ll tell you which plants to decorate a flower garden in the shade, and which ones to decorate in the sun. If, with this article in your hands, you don’t win against your neighbors in a flower garden competition, then you really aren’t striving to win.
Describing aster flowers in gardening publications is a real punishment for a botanist. The fact is that these are not flowers, but inflorescences. What normal person considers a petal to be a flower (reed or pseudo-reed, depending on the structure), the fluffy center of the flower is a collection of tubular flowers. But reluctantly I will try to be understandable, although I will bend the truth.
Asteraceae – helenium
I'll start my story with Helenium hoopesij. Many of you are familiar with it close relative Helenium autumnalis is a bright plant that blooms at the end of summer. In comparison, Helenium Hoop can be considered almost small, because its height does not exceed 80 cm. And in general, they cannot be confused at all. For example, the leaves of this species are large, up to 50-60 cm long.
But most importantly, it blooms much earlier - in June-July for 40 days. In one place, Helenium Hula can grow up to 7-8 years, then the plant must be divided, since aging bushes lose their decorative properties. This species can be divided both in spring and autumn. The plant also reproduces well by seeds (unlike varieties helenium autumn, which do not save external signs when reseeding). The best place for it in the garden is sunny areas with rich, loose and moderately moist soil.
Aster family - Echinacea
Echinacea purpurea- from a personal perennial plant. And we still come across another name - rudbeckia purpurea, although it has officially become outdated for a couple of hundred years. By the way, translated from Latin the word “echinacea” means “prickly”, this is due to the fact that the middle of the echinacea flower is prickly, like a disturbed, curled up hedgehog.
Echinacea purpurea has pale purple petals with a red-brown center. Echinacea blooms for a long time - from mid-July to September.
Even wild Echinacea bushes, due to their numerous stems up to 100 cm high with fairly large (up to 12 cm in diameter) flowers, look very decent. However, now “savage” is practically not grown, being tempted by varieties that surpass the original appearance in both shape and new colors, including orange and even yellow. And you won’t surprise anyone with a white one for a long time. So, very interesting, quite old, but time-tested white variety White Swan, in Russian translation it sounds like “ White Swan" Of the more modern white-flowered varieties, it should be noted White Luster, forming a powerful bush up to 120 cm high.
Of the pink-flowered varieties, mention should be made light pink Lilliput- the name itself speaks of its height; it is quite small and reaches only 45 cm. Terry is also interesting variety Razzmatazz with large double inflorescences with a diameter of 12 cm and a plant height of about 75 cm.
IN last years original varieties appeared, completely different in color scheme from standard pink and white. Thus, varieties with orange and yellow reed flowers appeared. There are also variegated ones, in which the color of the reed flowers is two-colored, for example, yellow with an orange-red honey mushroom. All new varieties have a complex hybrid origin from various species of Echinacea.
Species echinacea and the very first varieties (with pink or white simple baskets) are quite unpretentious, preferring illuminated areas with moderately moist, rich garden soils. But still they do not differ in longevity. If young plants are very resilient, then over time, a large, powerful bush can, in one miserable winter, just up and leave without a trace without declaring war. That is why you should not delay replanting and dividing for a long time; this operation must be carried out at least once every 4-5 years, otherwise you may simply lose the plant.
But with modern varieties the situation is completely different. They are much more capricious; in snowless winters they can freeze, but in warm winters they can get wet or frozen. And their lifespan is much shorter. My advice is that if you want to preserve the variety you like, be sure to divide the plant into small sections every spring (late May or early June). If the plant has not overwintered well and it is difficult to get a part with roots from what is left, take the cuttings. Echinacea reproduces well by cuttings. The optimal solution is a cutting with part of the rhizome. It must be planted under a glass jar in a semi-shaded place and watered regularly, making sure that the soil does not dry out. And new rooted plants can be planted for growing in just three weeks.
Echinacea can be used both in various flower beds and in separate groups against the background of a lawn. Some varieties can also be used as cut flowers.
Asteraceae - heliopsis
To fill your flower garden with a warm yellow hue, plant in your garden rough heliopsis (Heliopsis scabra). This is a bright, sunny plant. That is why it received such a scientific name, which translated from Latin means “similar to the sun.” Heliopsis - perennial herbaceous plant, resistant to the conditions of central Russia. It is quite tall, up to 1.5 m, and over time forms a thicket. The specific name of Heliopsis rough is due to the fact that its leaves are covered with small bristles that are rough to the touch. Heliopsis petals are yellow or orange, and the center is yellow or brown. The flowers themselves are quite large, and depending on the variety they can be single (or single), semi-double or double. Heliopsis blooms profusely and continuously from the second half of June until autumn. The culture is unpretentious, but does not tolerate excessively wet soils. Heliopsis grows well and blooms only in sunny areas. Since the plant grows quite quickly, once every 3-4 years the overgrown bushes need to be divided. When planting, the distance between plants should be at least 40-50 cm.
Now there are a number of interesting varieties.
Goldfeeder-terry flowers, golden yellow. Blooms profusely in July–August. Plant height up to 140 cm.
Neue Hybriden- flowers are simple, yellow in color. Blooms in July-August. Plant height is about 140 cm.
Another great variety - Asahi, its bright, densely double yellow-orange flowers are not too large, but there are a lot of them, and the bush itself is quite compact.
Among the varieties of heliopsis there are also variegated ones, with bright, occupying most leaves with white or pink-white spots, but they are less stable, and their flowers are much smaller.
Aster family - coreopsis
An equally colorful plant is the large-flowered coreopsis (Coreopsis grandiflora). It will decorate any composition in your garden, the only pity is that this plant is short-lived. Depending on the variety, 
coreopsis can reach a height of 60-80 cm. In a non-flowering state, coreopsis is hardly noticeable, because its thin dissected leaves are lost against the background of other plants. But from June until autumn, coreopsis is completely covered with bright yellow flowers.
U coreopsis lanceolata elongated lanceolate leaves. Plants are more compact, 50-60 cm high. Particularly impressive terry varieties. Yes, y Early Sunrise golden-yellow terry baskets decorating the garden from the second half of June to August.
All coreopsis are plants of sunny areas with loose, moderately moist soils. The easiest way to propagate coreopsis is by seeds, although young plants can be tried and divided. Since coreopsis ages quickly, be sure to replant young plants regularly.
Aster family - gaillardia
Well, what if yellow color not enough for you, add yellow-orange-red shades to your garden palette Gaillardia grandiflora. Gaillardia reaches a height of 30-70 cm. Against the background of oblong leaves, in the second half of June and until September, numerous, rather large baskets appear. The petals can be yellow, red, orange or variegated in various color combinations, and the center has a red-brown tint. Guylardia, like coreopsis, is a young plant, usually in the 4-5th year it loses its decorative effect and dies. Fortunately, it reproduces well by seeds. Gaillardia can also be propagated vegetatively by dividing the bush. In order for the plant to remain decorative, it must be divided and replanted regularly, every 3-4 years. It needs sunny areas with moderately moist fertile soils.
Asteraceae - navel flower
Dying navel (Anthemistinctoria)– a fairly compact (up to 30-60 cm high) plant for the garden. Its delicate, finely cut dark green leaves, which persist in winter, are very, very elegant. Well, the numerous bright yellow small baskets that appear in July-September decorate this plant even more. The navel is a young plant, but it reproduces well by seeds and produces abundant self-sowing, so much so that in favorable conditions it can turn into a weed. In addition to seeds, it can also be propagated vegetatively by division. The best place for it is sunny, dry areas.
Anaphalis from the aster family
Beautiful in the flower garden and Anaphalis margantacea- a compact plant 30 cm high. The whole plant is silvery-white and fluffy.
Its narrow oblong leaves are densely pubescent, but the most impressive are the numerous small snow-white baskets.
Anaphalis blooms very profusely and for a long time - from July to September.
It propagates both by seeds and by dividing overgrown bushes. The poorer and drier the soil, the better for this plant, and of course, do not forget to choose the brightest place in the garden for it.
Yarrow
And of course, we must not forget about common yarrow (Achillea millefolium). Let natural look is completely dim and its white or pale pink corymbose inflorescences look rather modest, but it blooms for a long time - from June to autumn, and precisely closer to autumn, when there are already few flowering plants, you can appreciate it. However, why think about natural forms now, when there are many brightest varieties - bright red, dark crimson, cherry... And hybrid varieties have adopted yellow and orange colors into their palette.
There is also a more spectacular type of yarrow - meadowsweet yarrow (Achillea filipendulina). This species reaches a height of 70-130 cm. Compound-pinnate gray-green pubescent leaves with a strong balsamic scent adorn the garden from spring to autumn. But keep in mind that this foliage color is only possible on poor, dry soils. If the soils are rich and sufficiently moist, then the foliage will turn green. From July to the end of August, numerous small yellow baskets appear, collected in large shields.
Yarrows – unpretentious plants, loving bright sun and poor dry soils. They propagate both by dividing the bush and by seeds (there are variety mixtures on sale that are very decent in color). By the way, all yarrows are excellent plants for winter bouquets, because when dried their inflorescences retain their color and shape.
Small petals
If you are a lover of rich colors and lush flowering, then be sure to plant beautiful small petal (Erygeron speciosus). Its blue and purple, pink, and less often white inflorescences-branches, appearing in the second half of June - July, are so numerous that because of them the leaves are completely invisible. Over time, growing, the small petals form dense clumps, up to 60-80 cm high. Large groups consisting of varieties of different colors look especially beautiful. Scatter these groups throughout the garden and they will create bright accents. There are many varieties of small-petaled petals; in our country you can most often find only a few of them on sale:
- Azure Beauty with bright lilac semi-double flowers;
- Lady Hindlip Mii– semi-double pink flowers;
- Sommerneuschnee– white with pink tint flowers.
Do not forget to regularly, once every 3-4 years, divide the overgrown bushes, and then this plant will delight you for many years. Well, to make flowering more abundant, plant the small-petalled plant in a sunny area with rich and moderately moist soil, and of course, do not forget about fertilizing.
Silphium
Among the large plants that bloom in July-August. worth talking about silphium perfoliatum, a plant rarely found in cultivation. It is absolutely resistant to the conditions of central Russia. Over time, it forms a large clump up to 200 cm high. The leaves Silphium pierced foliage whole, ovoid in shape, with wavy jagged edges. And yet golden flowers are its main decoration.
Silphium is extremely durable and unpretentious, although it works better in rich and fairly moist soils. Can grow in both sun and partial shade. Although in partial shade the bushes become more compact, and flowering becomes less abundant. Since the plant is tall, then the best place for him in the flower garden is a long-range composition. By the way, it can become an excellent screen for decorating unattractive parts of the garden. In addition, this is a great way to isolate yourself from your neighbors, if you have. Of course, there is such a desire.
Elecampane is also from the aster family
Add yellow color to the garden elecampane (Inula helenium). This is a large plant, sometimes exceeding 250 cm. Elecampane is not only decorative, but also has medicinal properties. This species is most decorative from the end of June, when bright yellow inflorescences-baskets appear against the background of large oval leaves. At the time of flowering, elecampane is an excellent accent in the garden.
If this species is too big for you, get its opposite - elecampane (Inula salicina), only 30-60 cm high. This is a completely ordinary meadow plant.
Unlike its large brother, elecampane is good in mass. This species blooms a little later - from July to August. But at the time of its flowering, the entire meadow is buried in bright yellow, numerous, though not very large, baskets. So for compositions in the currently fashionable natural style, this is simply an irreplaceable plant.
Elecampane can grow both in the sun and in light partial shade. Elecampane is quite unpretentious to soils, but the maximum decorative effect possible only on fertile ones. loose and moderately moist soils. There are no problems with the propagation of this plant - it can be propagated both by seeds and vegetatively - by dividing overgrown bushes. By the way, if you do not remove faded inflorescences, elecampane can produce abundant self-sowing.
| Taxonomy on Wikispecies | Images on Wikimedia Commons |
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Inflorescence [ | ]
The main distinguishing feature of this family is that, as the name itself shows, its flowers are complex, that is, what is commonly called a flower is actually a whole inflorescence of small flowers - a basket. These small flowers sit on a common bed - the extended end of a peduncle, having a flat, concave or convex surface and are surrounded by a common involucre, a common calyx, consisting of one or more rows bracts(small leaves located on a peduncle) - it turns out something like a basket. Individual flowers are usually very small, sometimes very small, only 2-3 mm long. They consist of an inferior ovary, unilocular and single-seeded, at the top of which is attached a petaled corolla. At its base there is usually a row of hairs or bristles, several denticles or a membranous border. These formations correspond to a rudimentary calyx.
The corolla is fused-petalled, varies greatly in shape, but there are two most common types: tubular, with a regular five-tooth bend, and an irregular one, the so-called reed, and all five of its lobes grow together into one plate, bent in one direction. The other three common types are bilabial, pseudolingulate and funnel-shaped flowers. All asteraceae, with rare exceptions, have five stamens; they grow with their filaments to the corolla tube, and with their anthers they grow together into one hollow tube surrounding the style, which ends in a bipartite stigma of a different structure. The gynoecium is pseudomonocarpous, fused from two carpels, forming an inferior single-locular ovary with a single ovule.
In many plants of the described family, the heads consist only of tubular flowers, such as cornflowers, burdock, and artichoke. Others, like dandelion, goatweed (scorzonera), lettuce, chicory and others, have all ligulate flowers. Finally, still others have flowers of both types in each head: reed-shaped around the circumference, and tubular in the center (for example, sunflower, aster, dahlia, marigold, marigold, chamomile).
We can also mention the third type of corolla - bilabiate, in which three lobes of the corolla are directed in one direction, and the remaining two in the other.
The size of the inflorescence is usually small, up to several centimeters in diameter; and only in some species it reaches a diameter of 10-15 cm, and in cultivated sunflower, which has the largest inflorescence in the family, it can reach up to 60 cm. At the same time, in some types of wormwood, the height and width of the inflorescence does not exceed 2-4 mm .
Flower formula: ∗ C a (0 , p a p p u s) C o (5) A (5) G (2) ¯ (\displaystyle \ast Ca_((0,pappus))\;Co_((5))\;A_((5) )\;G_(\overline ((2)))) .
Leaves [ | ]
The leaf arrangement in Asteraceae is usually alternate, rarely opposite. Their size, shape, and degree of dissection vary greatly among different species; length varies from several millimeters to ( ) up to 2 m in Japanese butterbur ( Petasites japonicus).
Root [ | ]
Most species have a well-developed tap root. Often the root is tuberously thickened, as, for example, in burdock ( Arctium). Many species of the family develop contractile(i.e. retracting) roots; in plants with a basal rosette, they often ensure that the rosettes adhere tightly to the ground. Many Asteraceae have (fungal root).
Fetus [ | ]
Pollination [ | ]
Spreading[ | ]
Asteraceae are distributed throughout the globe, but they play a particularly important role in North America. They also live in significant numbers in Central Asia and throughout southern Europe, but towards the north the number of their species decreases significantly.
Economic importance[ | ]
Food [ | ]
Many species of Asteraceae belong to important cultivated plants. Among them, the first place is occupied by the annual sunflower, originally from Mexico, distinguished by the largest heads of the entire Asteraceae family (sometimes up to 50 cm in diameter). Tuberous sunflower (jerusalem artichoke, earthen pear), chicory, artichoke, lettuce, stevia, etc. are also cultivated.
Decorative [ | ]
Production[ | ]
Weeds [ | ]
Among the dangerous weeds we can distinguish plants from the genus Ambrosia ( Ambrosia), causing allergic hay fever. Ambrosia is originally from America, but has spread very widely throughout the world, including in Russia - five species out of 30. Weeds can also be classified as ( Galinsoga parviflora), cyclachena cocklebur ( Cyclachaena xanthiifolia), some types of sequence ( Bidens) and etc.
Classification [ | ]
The Asteraceae family includes the two largest subfamilies - Asteraceae ( Asteroidae) And ( ) .
In the literature, other names for these subfamilies are sometimes found - respectively Tubeflowers(lat. Tubuliflorae) and Reed(lat. Liguliflorae). This name for the subfamily Asteraceae is due to the fact that its representatives have mostly tubular flowers, and the marginal flowers are usually pseudolingulate. Representatives of the subfamily have all ligulate flowers.
The Asteraceae subfamily includes most genera and species of the Asteraceae family, that is, more than a thousand genera and more than twenty thousand species; the second subfamily includes less than a hundred genera and about two thousand species.
Asteraceae are the largest family of dicotyledonous plants. It contains from 1150 to 1300 genera and more than 20,000 species. Asteraceae are found almost everywhere where the existence of higher plants is generally possible - from the tundra to the equator, from sea coasts to alpine snows, on barren sands and on rich black soils.
Plants of this family are usually easy to distinguish from representatives of other families by their characteristic inflorescence-basket. The base of the basket is formed by an expanded inflorescence bed, or a common receptacle, on which flowers closely adjacent to each other are located. Outside, the common receptacle is surrounded by an involucre consisting of more or less strongly modified upper leaves. The main function of the wrapper is to protect the flowers from adverse external environmental influences. The leaflets (or leaflets) of the involucre are arranged in one, two or several rows. The sizes of baskets in wild asteraceae are most often small, with a diameter ranging from one to several centimeters. Only occasionally the baskets are larger - up to 10-15 cm in diameter, and in the cultivated annual sunflower (Ilelianthus annuus) they reach the size of a large dish in diameter - up to 60 cm. At the same time, many wormwood baskets are tiny - only 2 in height and in width -4 mm. The general receptacle can be more or less flat (as, for example, in a sunflower), but can also be concave, convex, cone-shaped or of other shapes. Its surface is often covered with films, bristles or hairs. These are modified bracts, and only the stripes may not be associated with the bracts (i.e., have a trichome nature). The number of flowers in the basket is also in certain correspondence with the size of the general receptacle. In annual sunflowers it often exceeds a thousand, but in the female inflorescences of species of the genus Ambrosia there are only 2 flowers, and the baskets of species of the genus Echinops contain only one flower.
Fig.1. Compositae. Eclinops globifer
1 - complex capitate inflorescence; 2 - separate inflorescence; i - a flower, the corolla is partially removed (a - collective hairs on the style). Oriental cocklebur (Xanlhium orientate): 4 - male flower; 5 - the same thing in longitudinal section; 6 - female inflorescence in longitudinal section; 7 - female flower; 8 - infertility in a longitudinal section (slightly enlarged).
The flowers of Asteraceae are usually small. The calyx is modified into a pappus (sometimes also called a fly or pappus). The pappus consists of a more or less significant number of different types of bristles, hairs, awns, or it is represented only by a membranous rim (crown). Sometimes the tuft disappears completely, and then the flower is completely devoid of a calyx. In more primitive Asteraceae, scales are clearly visible - the rudiments of a lobed calyx. The corolla is fused-petalled. Its shape varies greatly. It is more or less actinomorphic, in which case it is tubular; if the corolla is zygomorphic, then it is most often either ligulate or so-called bilabial. There are many transitional forms between these basic forms. The stamens, usually 5 in number, are attached to the corolla tube. The filaments of the stamens are free, and the anthers stick together with their sides, forming an anther tube through which the style passes. The anthers are mostly elongated, longitudinally dehiscent, introsular. Rarely, for example, in the genus Ambrosia, the anthers are free, and the filaments of the stamens are fused. The gynoecium consists of 2 carpels with a style that ends in 2 stigmatic lobes or branches; in sterile flowers the style is sometimes undivided. In fertile flowers, the lobes of the style protrude from the corolla and often diverge greatly. On the inside of the stigma blades, they are equipped with a special receptive (stigma) tissue. Many species of the family are characterized by the presence of so-called collecting or sweeping hairs, which help remove pollen from the anther tube. The location of these hairs (in the form of a collar under the stigmatic lobes or on a more or less significant extent of the outer side of the lobes), their density and length are very diverse. The ovary is inferior, unilocular, at the base with one ovule (very rarely there are two), located on a short placenta (funiculus). In mature seeds, there is no endosperm or only traces of it are found.
The fruit of Asteraceae is an achene. This is a single-seeded, indehiscent fruit with a more or less dense, leathery and usually thin pericarp, usually separated from the seed. Only in very rare cases, as in species of the neotropical genus Wulffia, are achenes with a succulent pericarp. Brief information about the flower and associated structures, which were described above, refer to the well-developed bisexual flower of the Asteraceae. However, not all species of this family have all the flowers in the basket bisexual and fertile. Often there are 2 more types of unisexual flowers - female (usually fertile) and male (sterile), as well as sterile flowers in which both the androecium and gynoecium are reduced. The basket can be uniformly flowered (homogamous), but more often heterogeneous (heterogamous). In this case, the center of the basket is occupied by bisexual tubular flowers, and female and often brightly colored reed flowers radiate along the periphery. In a heterogamous basket, other combinations of flowers are observed, different in structure and sex.
Fig.2. Compositae fruits
1 - salsify (Tragopogon paradoxum); 2 - thistle (Cirsium arvense); 5 - golden rod (Solidago virga aurea); 4 - godson (Senecio); 5 - succession (Bidens tripartita); 6 - dipterocoma (Dipterocoma pusilla) - basket; 7 - prickly cocklebur (Xanthium spinosum) - basket; 8 - large burdock (Arctium majus) - basket
The leaves are mostly alternate. The size, shape and degree of dissection of the leaf blade vary greatly, from very large, like that of the Japanese butterbur (Petasites japonicus) growing on Sakhalin, the Kuril Islands and Japan (the blade of its entire basal kidney-shaped leaf reaches 1.5 m in diameter, and the petiole is 2 m long m), to small, very reduced ones, like the American leafless baccharis (Baccharis aphylla) with twig-like photosynthetic stems. The leaves of some American vines from the genus Mutisia are very original. In most Asteraceae, the leaves are characterized by one or another type of pinnate venation. However, there are leaves with strictly parallel or parallel-arcuate venation, as in some species of the genus Scorzonera. Many Asteraceae are characterized by pubescence. The hairs of Asteraceae are very diverse: single- or multicellular, hard and soft, straight and tortuous, simple (unbranched) or bifid, star-shaped. Dense pubescence is especially often well expressed in species living in conditions of constant dryness or sudden changes in temperature. Thus, growing in Central Asia, cotton wool (Lachnophyllum gossypinum) in its young state is covered, like cotton wool, with soft tangled hairs. Speaking about the aerial parts, we should also mention the noticeable percentage of thorny plants among the Asteraceae. The leaves and stems are prickly. The vast majority of species of the family have a developed tap root. Often the root is tuberously thickened, which, for example, is characteristic of burdocks (species of the genus Arctium). Many species of the family develop contractile (retracting) roots; in plants with a basal rosette, they often ensure that the rosettes adhere tightly to the ground. The beautiful tree plant (Fitchia speciosa), growing on the island of Rarotonga (Cook Islands), has well-defined aerial supporting roots. Endomycorrhiza has been found in many Asteraceae.
Most Asteraceae are herbs, either perennial or annual, that range in size from very large, like some sunflowers, to tiny. But among them there are also many subshrubs and shrubs. Shrubs - from 1 to 3 m and only sometimes higher (up to 8 m). Trees, usually low, are also found among the Compositae. Many tree forms are characteristic of oceanic islands. As part of the genus Scalesia, endemic to the Galapagos Islands, species are known with trunks reaching a height of more than 20 m with a diameter of 25-30 cm, such as S. pedunculata. They form real forests. Charles Darwin mentions them in his famous “Diary of Research in Natural History and Geology...” (better known to Russian readers under the title “A Voyage Around the World on the Beagle”). In South Africa and Madagascar, dioecious woody plants of the genus Brachylena (Bracjiylaena) grow, and among them is a tree of the first size endemic to Madagascar - Brachylena merana (B. merana). It reaches a height of 40 m and a diameter of up to 1 m; Its wood is resistant to rotting and is highly valued.
Like representatives of the order Campanaceae, the main storage carbohydrate in Asteraceae is inulin (and not starch, as in most other dicotyledons). Many Compositae belong to plants with a high degree of sensitivity to light, which is expressed in the ability to open and close the baskets, depending on the intensity of light. Often this sensitivity is so pronounced that it is easy to observe without resorting to any instruments. That is why among the flower clocks that were proposed in the first half of the 18th century. K. Linnaeus, Asteraceae are especially abundant. Flower clock is a set of plants planted in a small area, the flowers of which open and close at a certain time on clear sunny days. The accuracy of such watches is from half an hour to an hour. For each area, the set of plants should be different, previously established by observations.
Among the Asteraceae there are so-called compass plants. At midday, they are able to position their leaves with their edges facing the light falling on them; in this case, one wide side of the plate faces east, and the other faces west. This arrangement of leaves protects against overheating by the sun's rays and helps reduce transpiration, without reducing the intensity of photosynthesis. Compass plants are usually inhabitants of open areas. Of these plants, the wild or compass lettuce (Lactuca serriola), widespread in Eurasia, and the North American lobed silphium (Siphium laciniatum) are well known. At a time when the vast expanses of the American prairies were still poorly developed, the position of silphium leaves replaced a compass for lost hunters. The responsiveness of some Asteraceae not only to light, but also to air humidity and other atmospheric phenomena has long been noticed by people. Therefore, species of this family serve as a kind of barometer. So, if the basket of the sow thistle does not open on a more or less clear day, then rain is very likely the next day. The literature also contains data on longer-term “predictors” of weather among Asteraceae; it is indicated, for example, that the formation of a rosette of leaves in Helenium autumnale is associated with the nature of the upcoming winter.
Fig.3. Helenium (lat. Helenium), variety Dunkle Pracht
The vast majority of Asteraceae are insect-pollinated plants. Early spring species from temperate regions often have golden or orange-yellow flowers in the basket, which stand out well in dark soil that is still lightly covered with other plants. In many Asteraceae, the inconspicuous tubular flowers of the basket are surrounded on the periphery by bright white, yellow or red large flowers, which are clearly visible from a great distance. These peripheral flowers are often sterile and perform no other function other than signaling. Insect-pollinated Asteraceae with small baskets, hardly noticeable individually, have more or less large, clearly visible common inflorescences. Insects visiting Asteraceae are attracted by nectar, usually secreted at the base of the style, as well as pollen. The main pollinators are bees, wasps, bumblebees and other Hymenoptera, as well as Lepidoptera. More rare pollinators are hoverflies (syrphids) and other dipterans, as well as beetles and representatives of other orders of the insect class. Often the same Compositae is visited not by one or two, but by a large number various types insects There is evidence that some species of the genus Mutisia are pollinated by birds. Most Asteraceae exhibit protandry. Just like in bellflowers, the anthers open while still in the bud and the pollen ends up inside the pollen tube even before the flowers open; at this male phase of flower development, the style is short and the lobes or branches of the stigma are still tightly closed; by the time the flower opens, the column lengthens and gradually, like a piston in a cylinder, pushes out pollen, as we have already seen in representatives of the lobeliaceae subfamily of the bellflower family. Of the features that ensure the success and accuracy of cross-pollination, of great interest is the peculiar pollen-feeding mechanism observed in quite a few Asteraceae, for example, in species of the genus Cornflower (Centaurea). They have sensitive filaments of stamens that have the ability to contract. As a result, when insects touch the stamens, the anther tube moves down, and the column with sweeping hairs located underneath carries out pollen, which falls on the insect. Many Asteraceae have adaptations that ensure pollination between different flowers within the same basket. In cases where cross-pollination for some reason does not occur, self-pollination usually takes place. It is ensured by the ability of the stigmatic lobes of the style to twist so that they come into contact with their own pollen.
Relatively few Asteraceae, such as species of the genus Cocklebur (Xanthium), exhibit protogyny. Anemophilia is common. It is considered as a secondary phenomenon and is characteristic of plants of wide open spaces, for example species of wormwood (Artemisia); their baskets, as a rule, are small, inconspicuous, collected in complex common inflorescences. Some Asteraceae have cleistogamous flowers. In addition to the normal sexual process, apomixis is often observed in Asteraceae, especially among representatives of the lettuce subfamily, for example in the genus Dandelion (Taraxacum). The number of fruits is very significant, and in many cases extremely large. The fruits are usually small and weigh negligibly. The length of the achenes often does not exceed 5 mm and the width is 1 mm. The largest fruits are found in the above-mentioned arboreal plant; they reach a length of 5 cm. Very often, achenes are equipped with hairs, bristles, papillae, and so on, and in some anthemideas (tribe Anthemideae), the achenes are covered on the outside with special mucilaginous cells, which apparently contribute to the germination of the primordia in dry conditions.
Among the Asteraceae there are many anemochores. Of primary importance for this is the tuft, located directly at the top of the achene or raised on an extended narrow tip - the spout. Typically, the crest consists of a different structure of hairs or bristles, which are hygroscopic and can act as a flying machine only in dry weather. The crest belongs to the most perfect adaptations of this genus in the plant world; its position - above the center of gravity - is especially successful when the crest is on the nose. In general, the crest-parachute of Asteraceae, as shown by special studies, is, as it were, calculated according to the exact laws of aerodynamics; it gives the achenes significant stability in flight and increases the dynamic lifting force acting on the achenes. The crests of Asteraceae with feathery hairs are especially perfect. Very small and light achenes of Asteraceae, such as those of wormwood, although they do not have a special aircraft, are also partially carried by the wind.
In Asteraceae, which grow near water, the primordia are often carried by water, for example, in some species of butterbur (Petasites), string (Bidens), etc. Among the Asteraceae there are many zoochoric species. In burdocks, when the achenes ripen, entire fruit baskets easily break off from the plants and, thanks to the tenacious leaves, the wrappers stick to the hair of animals and people’s clothing. For a relatively small number of species, the phenomenon of myrmecochory was also noted. The fruits of some Asteraceae are dispersed when their elastic stems or peduncles are swayed. These are the so-called ballista plants. Their achenes are completely without a tuft or have tufts of coarse hairs, and sometimes are too short to be suitable for dispersal by the wind. Among the Compositae there are also representatives belonging to the tumbleweed life form. They are characteristic of plants living in open (treeless) spaces, for example in the steppes. An example of them is the spreading cornflower (C. difusa), which in the former USSR grows in open places, mainly in the south of the European part and in the Caucasus.
In the last few centuries, when communication and transportation of various goods between continents and countries became intense, the exceptional fertility of some Asteraceae, combined with their unpretentiousness, allowed them to develop vast new spaces, many times larger than their original (natural) range. An example is the North American conyza (Conyza canadensis), which first appeared in Europe only in the 17th century and has now become cosmopolitan. There are also well-known cases when European Asteraceae, having arrived on other continents, began to displace the aborigines there. Thus, drooping thistle (Carduus nutans), introduced to North America from Europe at the end of the last century, has now become a widespread and difficult to eradicate weed there. Among the biological features of Asteraceae achenes, let us also mention the heterocarpy, or heterocarpy, observed in many species of this family. Heterocarp is well expressed in the officinalis calendula (Calendula officinalis), widely known for the shape of its curved achenes called “marigolds”. In one basket of calendula there are claw-shaped, navicular and ring-shaped achenes, as well as transitional forms between them.
Fig.4. Calendula officinalis (lat. Calendula officinalis)
The huge family Asteraceae includes 25 thousand species, found throughout the world in all habitats accessible to flowering plants. Asteraceae play a significant role in vegetation cover. Most members of the family are perennial or annual herbs, but in the tropics there are herbaceous and woody vines, shrubs and even trees. In the highlands of Africa and tropical America, the original rosette Asteraceae are known, and in the deserts one can find heavily pubescent cushion-shaped or shrubby, often prickly, leafless plants with green, flattened stems.
In Russia there are many wild and cultivated species of this family. A person is accompanied by asteraceae from the genera burdock, thistle, thistle, sow thistle, succession, coltsfoot, wormwood, etc. Many of them are nasty weeds. There are a lot of meadow and steppe herbs among the Asteraceae, of which the most famous are representatives of the genera hawkweed, chicory, yarrow, cornflower, and cornflower. A wide variety of Asteraceae is observed in Siberia and the Caucasus. A typical representative of the family is the North American sunflower, which has long been cultivated in the south of Russia.
The leaves of Asteraceae are simple, whole or dissected, alternate or less often opposite. Flowers are always collected in baskets, which are often grouped into complex aggregate inflorescences - spikes, racemes, panicles and even heads. The base of the basket is the expanded apex of the inflorescence, or the general receptacle, which can be concave, flat or convex. The size of the baskets can vary from a few millimeters to 10 or more centimeters, and the number of flowers in them ranges from 1 to 1000 or more. The corolla is always sphenolate, 5-membered. Based on the structure of the corolla in Asteraceae, tubular, funnel-shaped, bilabiate, false-ligulate and ligulate flowers are distinguished. The overwhelming majority of Asteraceae are pollinated by insects attracted by pollen and nectar released at the base of the style. The fruits of Compositae are dry, indehiscent achenes. Very often they are equipped with a fly - a tuft formed by the hairs of a modified calyx. Sometimes the hairs are carried out on a special outgrowth of the top of the ovary - the spout, and the flying achene, for example in a dandelion, resembles a miniature parachute. In other cases, as in the string, the bristles at the top of the ovary are equipped with spines and easily cling to animal fur or clothing. Along with many difficult-to-eradicate weeds, the Compositae family contains a significant number of plants that are very valuable to humans.
From food plants highest value has sunflower, some varieties of which produce seeds containing up to 60% edible oil. In Western Europe, artichokes are often bred, the fleshy bases of the inflorescences of which are consumed as a vegetable. Green vegetables High Quality gives lettuce salad. Jerusalem artichoke, or earthen pear, is primarily known as a vegetable plant - an extremely unpretentious frost-resistant plant that forms large tubers. Tarragon or tarragon are used as a spicy seasoning, and some types of wormwood are indispensable in creating the unique taste of most vermouths. Of the industrial plants, the most famous is safflower, which is suitable for producing food coloring.
There are many asteraceous ornamental beautifully flowering plants, mostly bred for cutting: chrysanthemums, gerberas, garden asters, dahlias, marigolds and others that came to us from different parts of the world. Many Compositae - medicinal plants, of which the most important are chamomile, wormwood, coltsfoot, marigold (calendula), tansy and a number of others.
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