动态第336页 - 绿手指 - 养花技巧、花生病了怎么办、花园打理和设计

2018年02月25日

Description: This biennial plant consists of a low-growing rosette of basal leaves up to 7" across during the 1st year. These basal leaves are up to 3½" long and ¾" across; they are green to greyish green, oblanceolate, dentate, and often slightly pinnatifid with shallow lobes. Their upper surface is often hairy, although they tend to become less hairy with age. During the 2nd year, Tower Mustard bolts during the spring and produces one or more flowering stalks up to 3½' tall. These stalks are light green to dull white, unbranched, hairless, and glaucous. Sometimes there may be a few hairs near the base of the stalks. The alternate cauline leaves are up to 3" long and 1" across. They are greyish green, lanceolate, smooth along the margins, hairless, and glaucous. Some of the lower cauline leaves may be dentate and slightly pinnatifid. The base of each cauline leaf clasps the stalk with a pair of basal lobes, which may be rounded or pointed. During cool spring weather, the cauline leaves may turn purple when they are exposed to full sun. Each stalk terminates in an elongated raceme of flowers and upright siliques (slender cylindrical seedpods). This raceme can become as long as the rest of the plant (up to 1¾' in length) and it has a tower-like appearance. Each flower at the apex of the raceme is up to 1/6" (4 mm.) across, consisting of 4 white or cream petals, 4 light green or yellow sepals, a stout style, and several stamens. The pedicels of the flowers and siliques are about ¼–½" in length. The blooming period occurs during late spring to mid-summer and lasts about 1½ months. Each flower is replaced by a slender cylindrical silique up to 2½" long. The siliques are held upright close to stalk of the raceme. Each silique contains 1 or 2 rows of slightly flattened ovoid seeds. These small seeds have narrowly winged margins and they are dispersed to some extent by the wind. The root system consists of a stout taproot. This plant spreads by reseeding itself. Cultivation: The preference is full sun to light shade, mesic to dry conditions, and loam, clay-loam, or rocky soil. This plant also tolerates soil containing sand or hardpan clay. It is fairly easy to grow from seed. Range & Habitat: The native Tower Mustard occurs occasionally in the northern half of Illinois, but it is uncommon in the southern half of the state (see Distribution Map). Habitats include various kinds of prairies (sand, gravel, black soil, or clay), rocky open woodlands, barren savannas, limestone glades, rocky bluffs, and abandoned fields. In Illinois, Tower Mustard has low fidelity to any particular habitat. It also occurs in Eurasia. [图片]Faunal Associations: Mostly small bees and flower flies visit the flowers for nectar or pollen. Occasionally various species of White butterflies (Pieridae) visit the flowers for nectar. The caterpillars of two Pierid butterflies, Anthocharis midea (Falcate Orangetip) and Euchloe olympia (Olympia Marble), prefer Arabis spp. (Rock Cresses) as a food source, particularly those Rock Cresses that are typically found in sunny habitats. The caterpillars of another Pierid butterfly, Pieris napi (Mustard White), reportedly feed on Rock Cresses, although this butterfly species hasn't been observed in Illinois since the 19th century. Little information appears to be available about the desirability of Tower Mustard as a food source for mammalian herbivores. However, the foliage is not particularly bitter nor peppery. Photographic Location: The webmaster's wildflower garden in Urbana, Illinois. [图片]Comments: Among the various Rock Cresses (Arabis spp. and related genera), Tower Mustard is mostly likely to be found in black soil prairies, although it also occurs in other kinds of habitats. The tower-like inflorescence gives this plant an odd appearance that is rather striking, especially when it becomes 3-4' tall. Because Tower Mustard is not difficult to grow and seems rather robust, it is rather surprising that this species is not more common. There are several Rock Cresses in Illinois, which can be found in either sunny or shady habitats, depending on the species. Some species have erect siliques that are appressed against the stalk of the raceme, while other species have siliques that are spreading or drooping. Tower Mustard belongs to the first group. Its appearance is similar to a very rare species, Arabis drummondii (Drummond's Rock Cress). This latter species has flattened siliques containing 2 rows of seeds and the style of its flowers is more slender than the style of Tower Mustard. Another species, Arabis hirsuta (Hairy Rock Cress), has hairs along at least the lower half of its flowering stalks, and it has flattened siliques containing a single row of seeds. The siliques of Tower Mustard are terete (round in cross-section). A scientific synonym of this plant is Arabis glabra.

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Miss Chen

2018年02月25日

Description: This annual plant is unbranched. It is usually 4-12" tall, and rarely becomes taller. The central stem is light green and deeply grooved, with lines of small white hairs along the ridges. The alternate leaves are also light green, and strongly clasp the stem. However, at the top of the stem are a pair of opposite leaves. These leaves are up to 1" long and nearly as wide. They are broadly cordate, with wavy or dentate margins that are slightly ciliate. Along the margins, the leaves may assume a purplish color in bright sunlight. There is a milky sap in both the stem and leaves. From each leaf axil in the upper half of the plant, are 1-3 flowers, although only one of these will be in bloom at the same time. Each flower is deep violet or purple and about ½" across. It has a short tubular corolla with 5 spreading lobes. There are darker lines of purple that converge toward the throat of the flower. The throat is whiter than the rest of the flower, from which emerges a prominent white pistil and several stamens. The blooming period occurs during the early summer and lasts about a month. There is no floral fragrance. This plant also produces self-pollinating flowers on the lower half of the stem, whose petals never open. The ovaries develop into small oval capsules, which split open into 3 parts to about the middle. This releases the numerous tiny seeds, which are lens-shaped and reddish brown. They are dispersed readily by the wind, and can be carried a considerable distance. The root system consists of a taproot. Cultivation: The preference is full sunlight, and mesic to slightly dry soil. This plant flourishes best in poor soil that is either gravelly or sandy. It doesn't tolerate much competition from taller plants. Foliar disease is not a significant problem during the period of active growth and blooming, after which this plant will fade away. [图片]Range & Habitat: The native Venus' Looking Glass is fairly common in the southern half of Illinois, but uncommon or absent in many areas of the northern half (see Distribution Map). Habitats include mesic to slightly dry sand prairies, gravel prairies, upland areas of black soil prairies, sandy savannas, lake borders, abandoned fields, and areas along railroads and roadsides, especially where it is gravelly or sandy. The habitats where this plant occurs have sparser and lower vegetation than many other areas as a result of poor soil or disturbance. Faunal Associations: Small bees are the most common visitors of the flowers. This includes Little Carpenter bees, Plasterer bees, Green Metallic bees, and other Halictine bees. The Plasterer bee Colletes brevicornis is an oligolege of Venus' Looking Glass. Other insect visitors include bumblebees, flies, small butterflies, and skippers. The seeds are too small to be of any interest to birds. Mammalian herbivores may consume this plant, although it is of minor importance as a food source. [图片]Photographic Location: The photographs were taken in a waste area along a gravel road near Champaign, Illinois. Comments: When it is sunny, the flowers open up during the morning, and remain open for the rest of the day. They are attractive, but rather small. The common name of this plant probably refers to the shiny seeds of a related European species. The seeds of Venus' Looking Glass are too tiny to appear shiny to the unaided human eye. In form and color, the flowers of this plant resemble the flowers of Campanula americana (Tall Bellflower), but the former are much smaller. An older scientific name for this plant is Specularia perfoliata.

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Miss Chen

2018年02月25日

Description: This is a herbaceous perennial plant about 2-4' tall and mostly unbranched, except toward the apex. The central stem is round, glabrous, and occasionally glaucous. The grey- or blue-green alternate leaves are up to 15" long and 1" across. They are linear, although wider at the base, where the leaves wrap around the stem in sheaths, than at the tip. They are also glabrous, with parallel venation and smooth margins, tending to bend downward towards the middle. The light violet to blue-violet flowers occur in small clusters on hairless flowering stems at the top of the plant. Underneath each inflorescence are 2 small bracts, each up to 3" long and less than ½" across. Each flower is about 1" across, with 3 rounded petals, 6 bright yellow anthers, and fine spidery violet hairs near the base. The flowers open up during the morning and close by the afternoon in sunny weather, but remain open longer on cloudy days. There is no floral scent. The blooming period occurs from late spring to mid-summer, and lasts about 1½ months, during which time only a few flowers are in bloom at the same time. The mature seed capsules split into 3 sections, each capsule releasing 3-6 oval to oblong, brown seeds. The root system is thick, fleshy, and fibrous, sending off occasional offshoots nearby. Cultivation: The preference is full or partial sun, and moist to slightly dry conditions. The soil can contain loam, clay, gravel, or sand – this plant is very adaptable. Sometimes the leaves develop brown blotches or turn yellow in response to harsh weather conditions, competition from other plants, or age. [图片]Range & Habitat: The native Ohio Spiderwort is a common plant throughout Illinois, except in the SE, where it is uncommon or absent (see Distribution Map). It is often found in moist to mesic black soil prairies and sand prairies. Other habitats include sandy black oak savannas, Bur Oak savannas, limestone glades, thickets and woodland borders, moist meadows near woods or rivers, roadside ditches, and areas along railroads (including the ballast). Plants are usually widely scattered, but sometimes appear in sizable colonies in disturbed areas. Faunal Associations: The most important pollinators of the flowers are long-tongued bees, especially bumblebees. Other visitors include Halictine bees and Syrphid flies. However, the Syrphid flies feed on stray pollen and are non-pollinating. Spiderwort is rarely bothered by insects, although Lema collaris (Leaf Beetle sp.) reportedly feeds on the foliage. Mammalian herbivores also eat the plant, including the White-Tailed Deer, Cottontail Rabbit, Box Turtles, and livestock. The foliage is non-toxic to these animals. [图片]Photographic Location: The close-up photograph of the flowers was taken along a railroad in Champaign, Illinois, while the photographs of the flowering plant and close-up of the stem were taken at the wildflower garden of the webmaster in Urbana, Illinois. Ohio Spiderwort is more resistant to the application of herbicides along railroads than most plants, which is one reason why it remains common in such areas. Comments: This is probably the most common Spiderwort in Illinois. The flowers are short-lived, but beautiful, particularly when they are viewed close-up. Ohio Spiderwort can be readily distinguished from Virginia Spiderwort by the absence of conspicuous hairs on the flowering stems near the inflorescence, and the greyish or bluish appearance of the thin leaves. It also tends to be taller and more spindly in appearance than other species of Spiderwort, and has smaller bracts subtending the inflorescence. The leaves and stems are reported to be edible – fresh or cooked.

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Miss Chen

2018年02月25日

Description: This perennial wildflower is ½-1½' tall. The erect central stem is light to medium green, terete, glabrous, and usually unbranched. Sheathed leaves with long floppy blades alternate along this stem. The leaf blades are 4-12" long and up to ¾" across; they are medium green, linear-lanceolate, parallel-veined, and mostly glabrous, except for occasional hairs where the blades emerge from the sheaths. The sheaths are glabrous with parallel veins; sometimes they have purple veins. Flowering Plant The central stem terminates in an umbel-like cyme of flowers and a pair of large leafy bracts. These bracts have the same characteristics as the alternate leaves, and they are similar in size. The slender pedicels of the flowers are about ½-1" in length; they are light green to purple, glandular-hairy, and rather floppy. Individual flowers are 1-1¼" across, consisting of 3 blue-violet or rose petals, 3 light green sepals with glandular-hairy exteriors, 6 stamens with hairy filaments and yellow anthers, and a pistil. The sepals are lanceolate-ovate, while the petals are ovate-oval; the petals are a little longer than the sepals. The blooming period occurs from late spring to mid-summer and lasts about 1½ months. Usually, only 1-2 flowers are in bloom at the same time. The flowers are usually open only in the morning, except on cloudy days, when they may remain open a little longer. Each flower lasts only a single day and there is no noticeable fragrance. The flowers are replaced by seed capsules about ¼" long that are 3-celled; they are oblongoid-ovoid or oblongoid-obovoid in shape. Eventually, each seed capsule splits open into 3 parts, releasing 2-6 seeds. The seeds are about 2-3 mm. in length, tan or gray, broadly oblongoid, and somewhat flattened; each seed has a heavily ridged outer margin and it is indented along one side with a point in the middle. The root system is fibrous and rhizomatous. This wildflower often spreads vegetatively by means of its rhizomes, forming colonies. [图片]Cultivation: The preference is full sun, dry-mesic conditions, and sandy soil, although it readily adapts to other kinds of soil. On fertile ground, competition from taller plants is poorly tolerated. Range & Habitat: The native Prairie Spiderwort is an uncommon plant that is found primarily in west-central Illinois (see Distribution Map). It is state-listed as 'threatened.' It is more common in areas further to the west. Habitats include upland sand prairies, hill prairies, barren areas along railroads, and roadside embankments. This wildflower can be found in both disturbed and high quality natural areas, especially where it is sandy. Faunal Associations: The flowers offer only pollen as a reward to insect visitors. These floral visitors include honeybees, bumblebees, Halictid bees, and Syrphid flies. However, most Syrphid flies are too small to be effective at cross-pollination. The foliage, and sometimes the flowers, of Tradescantia spp. are eaten by such leaf beetles as Lema collaris, Lema longipennis, Oulema cornuta, and Oulema elongata. In sandy habitats, Spharagemon collare (Mottled Sand Grasshopper) also feeds on Prairie Spiderwort. The non-toxic foliage is readily eaten by rabbits and other mammalian herbivores. [图片]Photographic Location: The photographs were taken at the webmaster's wildflower garden in Urbana, Illinois. Comments: Other common names of Tradescantia bracteata are Long-Bracted Spiderwort and Sticky Spiderwort. Prairie Spiderwort can be distinguished from other Tradescantia spp. in Illinois by its diminutive size (1½' tall or less) and the glandular hairs on its sepals and pedicels. The most similar species in Illinois is Virginia Spiderwort (Tradescantia virginiensis). Virginia Spiderwort is slightly taller 1-2½' than Prairie Spiderwort, and the hairs on its sepals and pedicels are glandless. Another species in this genus, Ohio Spiderwort (Tradescantia ohiensis), lacks hair on its sepals and pedicels, its foliage is more blue-gray, and it is significantly taller (2-3' tall).

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Miss Chen

2018年02月25日

Description: This annual plant is about ½–2½' tall and unbranched. The central stem is round and has numerous white hairs. The opposite leaves are about 2" long and ¾" across. They are broadly lanceolate and sessile against the stem, with smooth margins and fine white hairs covering the upper and lower surfaces. Each of the upper leaves usually have two small lobes at the base, which resemble ears. The inflorescence consists of a spike of flowers in the upper half of the plant. These flowers are purple, pinkish purple, or lavender. Each tubular flower is about ¾" long, with 5 short lobes that flare outward. Sometimes there are purple dots inside the corolla. The reproductive parts consist of 4 stamens and 1 stigma near the upper inner surface of the corolla. Each flower is subtended by a large green calyx that is hairy and divided into 5 triangular parts. The blooming period occurs during late summer and lasts about 3 weeks. A fruit develops within each calyx that contains numerous small seeds. At this time, the entire plant becomes reddish brown. These seeds are probably distributed by the wind to some extent. The root system consists of a central taproot and secondary roots – the latter are often parasitic on the roots of other plants. However, in the absence of a suitable host, Ear-Leaved False Foxglove can meet its own needs adequately through photosynthesis. Cultivation: The preference is full or partial sun and mesic conditions. This plant typically grows in rich, loamy soil. It appears to have few problems with disease. The seeds can be slow to germinate; it is possible that a heat treatment simulating the effects of a wildfire may be beneficial in this regard. Range & Habitat: Ear-Leaved False Foxglove is a rare plant that occurs in scattered counties throughout most of Illinois, except the extreme south (see Distribution Map). It is a native plant that is state-listed as 'threatened.' Habitats include mesic black soil prairies, thickets containing grasses and occasional shrubs, savannas, woodland borders, abandoned fields, and areas along railroads (particularly where remnant prairies occur). This plant is found in both high quality habitats and somewhat disturbed areas. It is intolerant of frequent mowing or grazing; however an occasional wildfire may improve germination of the seeds, as well as reducing competition from shrubs and other kinds of plants. Faunal Associations: Bumblebees are the most important pollinators of the flowers, where they seek nectar. Other long-tongued bees also visit the flowers, including miner bees and leaf-cutting bees. Little information is available about this plant's relationship to mammalian herbivores; because the foliage is not known to be toxic, it is probably consumed by them occasionally. [图片]Photographic Location: The photograph of the plant in flower was taken by Lisa Culp (Copyright © 2009) at a nature preserve in Cook County, Illinois, while the lower photograph was taken by the webmaster at a prairie remnant along a railroad in Iroquois County, Illinois. Comments: This wildflower is easy to identify because of the small basal lobes on some of its leaves. It is closely related to the purple-flowered Agalinis spp., which are also partially parasitic on other plants. In addition to its peculiar basal lobes, Ear-Leaved False Foxglove has wider leaves than the latter species.

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Miss Chen

2018年02月24日

Description: This is a perennial plant that branches sparingly, and it is up to 3½' tall. The alternate leaves are bipinnately or ternately compound, and tend to be aggregated toward the base of the plant. The basal leaves are up to 12" long and 6" across, while smaller leaves are sparsely distributed along the middle and upper portions of the stems. Sometimes there are minute stiff hairs at the base of the petioles where the compound leaves meet the stem. The leaflets have large blunt teeth, and often occur in pairs or triplets, with the terminal leaflets achieving the largest size. Each leaflet is up to 1" long and ½" across, lanceolate or ovate, and has wedge-shaped lower margins. The overall appearance of the leaves resembles Italian Parsley. Flowering Plant in Prairie Rounded compound umbels of light yellow flowers occur at the ends of the central stem and major side stems. Each umbel is about 3" across, and is composed of 12-20 umbellets. Each umbellet consists of a similar number of tiny flowers, each one with 5 petals. There is no noticeable floral scent. The blooming period occurs during the late spring or early summer, and lasts about a month. The root system consists of a central taproot. Cultivation: The preference is full or partial sun and mesic conditions. The soil can contain significant amounts of loam, sand, or rocky material. Light shade is tolerated, but growth will be less robust and flowering less abundant. Hairy-Jointed Meadow Parsnip develops rapidly during the spring, and is usually taller than the surrounding plants when the blooming period begins. After flowering, the condition of the plant rapidly deteriorates. [图片]Range & Habitat: This native plant occurs occasionally in scattered counties of Illinois. Its distribution is oddly bifurcated, consisting primarily of counties in east-central and west-central Illinois (see Distribution Map). Habitats include mesic black soil prairies, openings in forests and woodland borders, sandy savannas, rocky bluffs, and the borders of lakes. This plant occurs in prairies to a greater extent than has been realized in the past. Faunal Associations: Many kinds of insects are attracted to the flowers, especially short-tongued bees, wasps, flies, and beetles. The caterpillars of the butterfly Papilio polyxenes asterias (Black Swallowtail) feed on the foliage and flowers. This plant is not known to be toxic, and is probably consumed occasionally by various mammalian herbivores, although information about this is limited. [图片]Photographic Location: The photographs of the flowering plant and compound leaf were taken at Loda Cemetery Prairie in Iroquois County, Illinois. The photograph of the umbels and upper leaves was taken at a woodland in Vermilion County, Illinois. Comments: This native member of the Carrot family should be grown more often in wildflower gardens. Sometimes it is called 'Hairy Meadow Parnsip,' but conspicuous hairs occur only at the base of the petioles of compound leaves, and these are not easy to see unless you know where to look. This plant resembles the weedy and aggressive Pastinaca sativa (Wild Parsnip), but the latter has flat compound umbels of yellow flowers, while Hairy-Jointed Meadow Parsnip has compound umbels of pale yellow flowers that are more rounded. There are also significant differences in the structure of the compound leaves between these two species.

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Miss Chen

2018年02月24日

Description: This perennial plant is 3-7' tall, branching occasionally. The central stem is rather stout, green or reddish purple, and glaucous or slightly pubescent. The alternate leaves are ternately compound: A primary compound leaf divides into 3 secondary compound leaves, while each secondary compound leaf has 3 leaflets. Each leaflet is about ¾–2" long and half as much across. It is rounded at the base, and either unlobed or with 2-3 lobes toward the outer edge (usually a large middle lobe and 2 smaller side lobes). The margin of each leaflet turns downward slightly. The light green or white lower surface has a waxy appearance that is covered with glandular hairs. These hairs will glisten when they are exposed to sunlight. The lower surface of a leaflet also has a reticulated network of conspicuous veins. The foliage, when crushed in the hand, will produce a skunk-like smell. Female Plant with Immature Fruits Occasionally, the upper stems will produce panicles of flowers that are up to 2' long and about half as much across. Individual plants are usually unisexual, producing either male or female flowers. A male flower has 4-5 light green sepals that spread outward, while conspicuous white stamens with yellow or brown anthers occupy the center. Each male flower is about 1/3" long. The male flowers usually droop downward from slender pedicels, and together have an airy appearance that is rather pleasant. The female flowers are shaped like small green burs and have numerous short pistils. They are less attractive than the male flowers. The blooming period is from late spring to early summer, and lasts about 3 weeks. There is no floral scent. Pollination is by wind. The flowers are replaced by small achenes that are ribbed and pointed at both ends. The root system has rhizomes, which enables vegetative colonies to form. This plant gradually dies down during the summer, but forms new vegetation at the base during the fall. Cultivation: The preference is moist to slight dry conditions, and partial to full sun. This plant usually grows in fairly typical garden soil, such as a rich loam or clay loam. The height of a plant can vary considerably depending on fertility of the soil, moisture conditions, and maturity. Vegetative growth is very rapid during the spring. This species of Meadow Rue appears to tolerate full sun and droughty conditions better than most. [图片]Range & Habitat: Waxy Meadow Rue is widely distributed in Illinois, where it is native. This plant occurs occasionally in central and northern Illinois, but it is less common or absent in southern Illinois (see Distribution Map). Habitats include mesic black soil prairies, thickets and woodland borders, savannas, and areas along railroads and roadsides, especially where remnant prairies occur. Faunal Associations: Because the flowers are wind-pollinated, few insects visit the flowers. Occasionally bees gather pollen from the anthers of the male flowers, while various kinds of beetles eat the pollen. Because the foliage has a foul scent, it probably is not a preferred food source for mammalian herbivores. Photographic Location: The photographs were taken at the Red Bison Railroad Prairie in Savoy, Illinois. The plants were growing in full sunlight under mesic conditions. [图片]Comments: This plant is reasonably attractive while in bloom, but this doesn't last very long. The various Thalictrum spp. have very similar flowers, but can be distinguished by their foliage. Waxy Meadow Rue has glandular hairs on the undersides of the leaflets (which glisten in the sunlight), and the foliage has a foul scent when it is crushed. Another species, Thalictrum dasycarpum (Purple Meadow Rue), has a very similar appearance, but the hairs on the undersides of the leaflets (if present) are non-glandular, while the foliage has little scent. Either of these plants can occur in prairies. Another species that is fairly common in Illinois, Thalictrum dioicum (Early Meadow Rue), is a shorter plant that blooms earlier and occurs in woodlands. However, the terminal leaflets of this species have 5 lobes toward the outer margin, while the terminal leaflets of Waxy and Purple Meadow Rue have only 3 lobes.

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Miss Chen

2018年02月24日

Description: This perennial wildflower consists of a rosette, or clustered rosettes, of basal leaves from which one or more flowering stalks develop. The ascending to spreading basal leaves are 1-6" long and 1/8–1/2" (3-12 mm.) across; they areColonies of Flowering Plants dark green, linear-oblanceolate in shape, smooth along their margins, and mostly hairless. The leaves of plants that are under stress from drought may become grayish green. Individual flowerheads develop at the apex of unbranched stalks that are 4-12" high; these flowering stalks are more or less erect. The stalks are rather stout and more or less finely pubescent. Individual flowerheads span 1-1¾" across, consisting of 10-30 ray florets that surround a dense cluster of 50 or more disk florets. The petal-like rays of the ray florets are ¼–¾" long, bright yellow, oblong in shape, and divided into 3 blunt teeth at their tips. The tiny disk florets are golden yellow, tubular in shape, and lobed along their upper rims. Both ray and disk florets are fertile. Around the base of each flowerhead, there are green floral bracts (phyllaries) in 2-3 series. Individual floral bracts are about ¼" in length, finely pubescent, and oblong-ovate with rounded tips. The blooming period usually occurs from late spring to early summer. A colony of plants may bloom for about a month. The florets are replaced by small achenes that are angular and finely pubescent; they become mature during the summer. At the apex of each achene, there is a tiny crown of 5 or more chaffy scales that are lanceolate in shape. The achenes are distributed by gravity and wind, although they usually don't travel far from the mother plant. The root system consists of a short stout caudex that eventually branches, forming a cluster of plants from vegetative offsets. Cultivation: The preference is full sun, well-drained mesic to dry conditions, and a gritty alkaline soil containing gravel or rocky material. This wildflower can be cultivated in rock gardens. The seeds require no winter dormancy and should be sowed during the same year that they are produced. Range & Habitat: Lakeside Daisy is a rare native wildflower in Illinois, having been found in only Tazewell and Will counties (see Distribution Map). It is state-listed as 'endangered' and federally listed as 'threatened.' At one time, this wildflower was extirpated from the wild in Illinois, although it still existed in private gardens in the Chicago area. More recently, it has been successfully reintroduced in various natural areas of the state. The largest population in the United States exists in Marblehead Peninsula along Lake Erie in Ohio. Habitats consist of dry dolomite prairies and gravel prairies, gravelly hill prairies, sand-gravel terraces along major rivers, ledges along cliffs, and limestone quarries. This wildflower is found in rocky areas with sparse vegetation and can tolerate minor amounts of disturbance. [图片]Faunal Associations: Both nectar and pollen are available from the flowerheads, which attract bees, flies, beetles, butterflies, and skippers. Floral bee visitors include bumblebees, small carpenter bees (Ceratina spp.), and Halictid bees. Cross-pollination is required because individual plants are genetically self-incompatible. Insects that feed on the Lakeside Daisy include grasshoppers and the larvae of an unidentified weevil; the latter feeds on the seeds. The flowering stalks are eaten occasionally by the White-Tailed Deer and Cottontail Rabbit. In the Western states, related species in the Hymenoxys/Tetraneuris complex are known to have toxic leaves that can poison cattle and sheep, however the toxicity of the more eastern Lakeside Daisy has not been determined. Photographic Location: A botanical garden in the Chicago area. The photographs of the Lakeside Daisy were taken by Jim Ault (Copyright © 2010). [图片]Comments: The Lakeside Daisy is an attractive plant. This wildflower is rare because of its restrictive habitat requirements and the limited distribution of its seeds. Lakeside Daisy is one of several spring-blooming species in the Aster family that have yellow flowerheads and rosettes of basal leaves. It can be distinguished from these other species by its narrow dark green leaves, unbranched flowering stalks, three-toothed rays, and achenes with tiny crowns of scales (rather than a tufts of hairs). Other closely related species exist in the Western states. The Lakeside Daisy is sometimes classified as var. glabra of the western Hymenoxys acaulis. However, this latter species differs by having fewer ray florets (less than 15), floral bracts (phyllaries) with awned pointed tips, and basal leaves that are gray-green with silky hairs.

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Miss Chen

2018年02月24日

Description: This perennial wildflower is 1-2' tall, sending up one or more stems from the base that are unbranched or sparingly branched. The stems are light green, terete, and hairy. Alternate compound leaves are widely spreading; they are odd-pinnate with 9-25 leaflets. Individual leaflets are up to 1" long and ¼" across; they are medium green to grayish green, oblong to narrowly elliptic in shape, and smooth along their margins. Upper surfaces of the leaflets are hairless to silky-hairy, while their lower surfaces are pubescent to silky-hairy. Each leaflet has a prominent central vein. The central stalk (rachis) and petiole of each compound leaf is pubescent. At the base of each petiole, there is a pair of small stipules about ¼" long. The stems terminate in short dense racemes about 2-3" long that are covered in buds and bicolored flowers facing all directions. The racemes are held a little above the foliage on short peduncles. Individual flowers are ¾" long and across, consisting of 5 petals, a short tubular calyx with 5 teeth, 10 stamens, and a pistil. Each flower has a typical pea-like floral structure, consisting of an upright banner and a pair of lateral wings that project forward to enclose the keel. The broad banner is white to pale greenish yellow, while the wings are deep rosy pink. The pedicels of the flowers and their calyces are light green and pubescent. The blooming period occurs from early to mid-summer and lasts about 3 weeks. Afterwards, the flowers are replaced by widely spreading seedpods about 1½-3" long. These seedpods are initially light green, but later turn brown; they are silky-hairy. The seedpods are narrowly cylindrical and slightly flattened in shape; each pod contains several seeds that are reniform and somewhat flattened. The root system consists of a deep taproot. Cultivation: The preference is full or partial sun, mesic to dry conditions, and an acidic sandy soil. Goat's Rue adds nitrogen to the soil. Range & Habitat: The native Goat's Rue is occasional in all areas of Illinois, except the east-central section, where it is absent (see Distribution Map). Habitats include upland sand prairies, sandy hill prairies, sand dunes, upland sandy savannas, upland rocky savannas, and sandstone glades. In more wooded areas, Goat's Rue typically occurs where oaks are the dominant trees. Faunal Associations: The nectar and pollen of the flowers attract leaf-cutting bees (Megachile spp., Hoplitis spp.) and possibly other long-tongued bees. The caterpillars of the skipper, Thorybes bathyllus (Southern Cloudywing), feed on the foliage of Goat's Rue and other species in the Bean family. Other insect feeders include caterpillars of the moth Semiothisa eremiata (Three-lined Angle), seed-eating larvae of two straight-snouted weevils (Apion segnipes, Apion perforicolle), the plant bug Teleorhinus tephrosicola, the blister beetle Epicauta murina, and several leaf beetles (Bassareus lituratus, Odontota horni, Odontota notata, Pachybrachis othonus, Phyllecthris gentilis). Among vertebrate animals, the seeds are eaten by the Wild Turkey, while cattle have been observed to browse on the foliage. The roots contain rotenone, which is toxic to insects and fish. [图片]Photographic Location: The photograph of the flowering plant was taken by Keith & Patty Horn (Copyright © 2009) at a prairie in Fayette County, Illinois. The photograph of the plants with mature seedpods was taken by John Hilty at Hooper Branch Savanna Nature Preserve in Iroquois County, Illinois. Comments: Because of its attractive bicolored flowers and widely spreading seedpods, Goat's Rue is fairly easy to identify. If only the foliage is present, then it is possible to confuse this wildflower with Amorpha canescens (Leadplant), Dalea foliosa (Leafy Prairie Clover), and possibly other species in the Bean family. These latter two species have very short seedpods and their flowers are much smaller in size than those of Goat's Rue. Across different populations of Goat's Rue, there is considerable variation in the hairiness of the foliage. Western populations that are found in sunny habitats often have leaflets that are densely covered with silky hairs, while eastern populations that occur in more shaded habitats have leaflets that are less conspicuously hairy.

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Miss Chen

2018年02月24日

Description: This herbaceous perennial plant is ½–2' tall, producing one or more leafy stems that are erect, ascending, or sprawling. The wiry stems branch sparingly, and they are often curved, arching, or crooked. Young stems are whitish green to silver-colored and terete; they are moderately to densely covered with fine pubescence. Older stems are brown or purple and sparsely to moderately covered with fine pubescence. Alternate leaves occur along the entire length of each stem, becoming slightly smaller in size as they ascend. The leaves are ½–1¼" long and about 4-8 mm. across; they are oblong to elliptic in shape and entire (smooth) along their margins. The bases of leaves are sessile or clasp their stems slightly, while the tips of leaves are short-acute. Both the upper and lower surfaces of leaves are whitish green to silver-colored; they are moderately to densely covered with appressed fine pubescence. The upper stems terminate in one or more flowerheads. On a robust plant, this inflorescence resembles a little-branched open panicle up to ¾' long that has 6-18 flowerheads, otherwise the inflorescence consists of 1-2 short branches with 1-3 flowerheads at their tips or slightly below. The wiry branches of the inflorescence are terete, whitish green to silver-colored, and moderately to densely covered with fine pubescence. Along the branches of larger inflorescences, there are leafy bracts that resemble the alternate leaves. The daisy-like flowerheads are about 1¼" across, consisting of 10-22 ray florets that surround numerous disk florets. The petaloid rays of the flowerheads are linear-oblong in shape, widely spreading, and lavender, deep lavender, or various shades of purple. The tiny corollas of the disk florets are tubular in shape with 5 lanceolate lobes along their upper rims; these lobes are erect to ascending. During the period of bloom, the corollas of the disk florets are white to pale pinkish purple; their anther tubes are yellow and their stigmas are lavender to purple. The blooming period occurs from late summer into autumn, lasting about 1 month for a colony of plants. Afterwards, the florets are replaced by achenes. These achenes are 2-3 mm. long and bullet-shaped with small tufts of hair at their apices; they are dispersed by the wind. The root system is fibrous and occasionally rhizomatous; older plants form short caudices. Occasionally, clonal offsets are produced from rhizomes. [图片]Cultivation: The preference is full sun and mesic to dry conditions. Almost any kind of soil is satisfactory if the site is well-drained, but this plant typically grows in poor soil that is rocky or sandy. A high pH is tolerated. Overall, this plant develops more slowly than most perennial asters (Symphyotrichum spp.) and it is a bit more difficult to grow. It doesn't tolerate much competition from taller ground vegetation. While the drought tolerance of mature plants is good, some of the lower leaves will wither away and fall from the stems. Range & Habitat: The native Silky Aster occurs primarily in the northern tier of counties and in many counties along the Illinois and Mississippi Rivers (see Distribution Map). It is an uncommon plant that appears to be declining in abundance as a result of habitat destruction. These habitats include upland dolomite prairies, gravel prairies, sand prairies, hill prairies, stabilized sand dunes, upland sandy savannas, limestone glades, and prairie remnants along railroads. This is an indicator plant of high quality habitats in dry open areas. [图片]Faunal Associations: The nectar and pollen of the flowerheads attract bumblebees, leaf-cutting bees (Megachile spp.), green metallic bees (Agapostemon spp.), Syrphid flies, and small- to medium-sized butterflies, including the endangered Karner Blue (Lycaeides melissa samuelis); see Reed (1993) and Swengel & Swengel (2000). Syrphid flies are probably non-pollinating. A plant bug, Psallus astericola, feeds on Silky Aster (Knight, 1941). Other insects that feed of the foliage and other parts of asters (Symphyotrichum spp.) include leaf beetles, the larvae of leaf-mining flies, the larvae of gall flies, other plant bugs, aphids, the larvae of moths, the larvae of butterflies, and grasshoppers. Among mammals, the young foliage of these plants are browsed occasionally by rabbits, deer, groundhogs, cattle, horses, and sheep. However, Silky Aster may be an exception to this rule, as it was found to increase in abundance as a result of grazing (Brudvig et al., 2007). Among birds, the Wild Turkey also browses on the foliage of asters; this upland gamebird and the Tree Sparrow also eat their seeds (Martin et al., 1951/1961). [图片]Photographic Location: The photographs were taken at the webmaster's wildflower garden in Urbana, Illinois. Comments: This is a truly beautiful little plant with attractive foliage and flowerheads. It's an excellent candidate as a wildflower in a sunny rock garden. In Illinois, Silky Aster (Symphyotrichum sericeum) can be distinguished from all other asters (Symphyotrichum spp.) within the state by its exceptional foliage, which has a silvery or silky appearance because of the numerous fine hairs covering its stems and leaves. It also has larger flowerheads (often exceeding 1" across) than most native or naturalized species of asters within the state. A scientific synonym of this plant is Aster sericeus.

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