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Miss Chen
2018年07月29日
Miss Chen
Philodendron is a genus of evergreen tropical plants most commonly kept as conservatory or house plants. Pruning requirements for tropical plants, including philodendrons, are minimal except for when leaves die back due to age or damage. Two main types of philodendron growth forms exist: trailing, also known as vining, and clumping, also called self-heading. Prune philodendrons sparingly when needed to preserve their natural form. Self-Heading Philodendron Step 1 Prune out individual leaves that have died or become discolored or diseased. Sever the leaf at the base of the stem down to the crown of the plant just above the soil line.
Step 2 Reduce the size or spread of the plants by removing the longest, oldest and most outsize leaves and stems down to the crown. Distribute these cuts evenly throughout the plant to maintain the natural form. Step 3 Remove any stems that have lost their leaves. Sever the stem stump down to the crown of the plant, just above the soil line. Vining Philodendron Step 1 Snip off any dead, discolored, diseased or otherwise unsightly leaves that appear on the vines. Remove either an individual leaf or whole sections of vine as needed to keep the plant looking green and tidy. Step 2 Cut back defoliated vines to just below a healthy leaf because the bare vines will likely not regenerate new growth once lost. Step 3 Prune away leaves on the vines that have become brown or yellow due to over-watering or lack of sufficient sunlight. Once this occurs, the leaves will not be restored to a deep green hue. Remove the leaves at the base of the stem. If the vine tip or a section of vine is damaged, cut back to a healthy green leaf node just above the damaged tissues.
Step 4 Cut back the tips of the vines as desired to bring the plant back within preferred bounds and reduce size and spread.
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Miss Chen
2018年07月29日
Miss Chen
If you enjoy growing tropical plants with colorful flowers, the plumeria plant (Plumeris spp.) could be an excellent choice for your garden or as a small indoor tree. Also called the frangipani or temple tree, the plant grows outdoors year-round in U.S. Department of Agriculture plant hardiness zones 9 through 11. You can help keep a plumeria tree in good shape and promote plenty of flowers by pruning it regularly.
The Best Method A plumeria tree is naturally short and stocky, developing a broad crown and reaching 12 feet or more when it's 6 years old, although this can vary with the variety. Some species, such as West Indian Jasmine (Plumeria alba), which grows in USDA zones 10 through 12, can grow 40 feet tall a if left unpruned. When cutting back a plumeria, use a sharp knife or pruning shears. For a tall plumeria, you might need a pruning saw mounted on a tall pole. Always make cuts at an angle so water won't collect in the cut end of the branch and encourage fungal disease. It's also important to prevent spread of diseases by disinfecting your pruning blades after each cut, wiping them well with rubbing alcohol or dipping them in a container of rubbing alcohol. Timing You can prune a plumeria tree at any time, but pruning an actively growing tree can leave unsightly branch stubs until new growth starts. The plant slows its growth in winter, dropping its leaves and looking bare until new ones appear in spring. During this dormant season, it's easy to see the tree's basic form, making pruning decisions easier. To allow the tree to set blossoms for the following season, prune lightly so that enough young growth remains to produce new flowers in spring. To keep the tree within bounds, you can repeat light winter pruning every year or two until the tree reaches a suitable size for its location. The Overall Plan If your plumeria is just few years old, you can help control its size in future years by heading it back every year or two, cutting healthy branches back by about one-third. This also encourages lots of new branches that help fill in the tree's shape as it grows and eventually produce flower buds. An older tree that's outgrown its space may respond well to a method called pollarding, which involves removing the upper branches from a mature tree to promote a dense canopy of foliage. This method reduces the tree's size and can keep a mature tree at a predetermined height. Regardless of the tree's age, how often you prune depends somewhat on the tree's response. If there's abundant new growth the following year, you can prune yearly, but if growth appears slowly, it's a good idea to skip a year or two between prunings.
After Pruning You can help stimulate a newly pruned plumeria to put out healthy growth by fertilizing it regularly during its growing season. Use a granular, 10-30-10 formula, applied at the rate of 1 pound per 1 inch of trunk diameter. Spread the fertilizer under the tree evenly, scratching it into the soil and distributing it to about 2 feet beyond its drip line, which is the outermost area where foliage extends over the ground. Providing adequate water also supports new growth, especially during summer dry spells -- supply enough water to keep the soil moist but not soggy, generally about 1/2 to 1 inch weekly.
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Miss Chen
2018年07月29日
Miss Chen
Long-lived, undemanding in care, and suitable for spreading groundcovers in woodlands and naturalistic gardens, wild geraniums are also known as cranesbills (Geranium spp.). Hundreds of species grow naturally across temperate regions in the Northern Hemisphere. Deep, slender taproots or rhizome stem-roots create clumping plants with lobed leaves that are reminiscent of both maples and ferns. Wild geranium's most ornamental feature is the five-petaled flowers in spring or early summer that are white, blue, violet, lavender or any shade of pink. Do not confuse them with florist geraniums (Pelargonium spp.).
00:49 Post-Flowering Maintenance Once wild geraniums finishing their first blooming display in late spring or early summer, cut back the entire plants to 3 or 4 inches tall to expose the tiny crown of leaves nestled in the lower leaf stems. Do not cut back the flower stems or entire plants if you want seeds to form and scatter in a newly planted area. The seeds will scatter naturally and lead to more plants next spring. In established gardens, trimming away the old flower stems limits the volunteer, weedy seedlings that may pop up all over the place. Trimming Tip Clipping back of old flower stems does improve the look of wild geraniums the rest of summer and into fall before frost. Use care when trimming the stems, as you can inadvertently cut off the frilly foliage stems if you do not grasp each flower stem before cutting. In expansive sweeps of wild geraniums in a woodland setting, trimming isn't practical, unless a power weed trimmer is used. Only focus hand-trimming efforts on plants in the more formal perennial border. Rejuvenation In regions with long, hot summers, some gardeners will cut back old, tattered and dead leaves in early to midsummer to rejuvenate. Wild geraniums tend to cease flowering in the hottest part of summer anyways, so cutting back old leaves to the base of plants -- just above the small lower rosette of young leaves -- allows the plants to produce lush, green plants with more blossoms in late summer and early fall. In milder winter regions, the foliage of some evergreen species will then often bronze or attain purplish hues and remain attractive if not matted down and suffocated by snow.
Trimming Insight If your patch of wild geraniums grows in an un-irrigated section of the landscape, or the soil isn't particularly moist and rich in organic matter on its own, cutting back the plants after the first flowering may not prove best. Only cut back plants if the soil will be evenly moist during the hottest part of summer. Postpone or cancel the plant trimming during years with drought, as the loss of tissues and dry soil can weaken or kill the perennial's roots. In dry years, letting flowers go to seed may ensure wild geraniums grow again next year once the drought ends.
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Miss Chen
2018年07月29日
Miss Chen
The process of deadheading -- or removing the wilted blooms from a flowering plant -- focuses the plant's energy into healthy root and leaf growth instead of seed production. In some plants, it also encourages the plants to bloom again. The various coneflower species respond well to deadheading, but there are also good reasons for not deadheading coneflowers. Coneflower Blooms Coneflowers all belong to the plant family, Asteraceae, and the blooms are similar enough they can all be deadheaded the same way, or left on the plant for the same reasons. Not every type of coneflower blooms at the same time, so be on the lookout throughout the summer and fall to deadhead in a timely manner.
The common name "coneflower" applies to several genera, including Echinacea, Rudbeckia and Ratibida. All have a cone-shaped flower center, though plants in the Echinacea genus are the ones most often referred to as "coneflowers." Purple coneflower (Echinacea purpurea), which grows in U.S. Department of Agriculture plant hardiness zones 3 through 8, has purple-pink petals around an orange center. It grows 2 to 5 feet tall, and blooms all summer Yellow coneflower (Echinacea paradoxa), which grows in USDA zones 5 through 8, grows 2 to 3 feet tall. It blooms all summer, and has thin yellow petals around a brown center. Black-eyed Susan (Rudbeckia fulgida), which grows in USDA zones 3 through 9, is a sturdy perennial that grows 2 to 3 feet tall and blooms midsummer through fall. The daisylike yellow flowers have a black center. Gray-head coneflower (Ratibida pinnata), which grows in USDA zones 3 through 8, grows 3 to 5 feet tall and blooms in the summer. It has thin yellow flower petals that fold back from a 1-inch gray center. Mexican hat plant (Ratibida columnifera), which grows in USDA zones 4 through 9, is also called long-headed coneflower because the flower center can reach 2 inches high. It grows 1 to 3 feet tall, has yellow flower petals and blooms in the summer and early fall. Missouri coneflower (Rudbeckia missouriensis), which grows in USDA zones 5 through 8, grows 2 to 3 feet tall and blooms summer through fall. It has orange-yellow flowers with a black center. Reasons to Deadhead Deadheading coneflowers can encourage rebloom. Purple coneflower and yellow coneflower will rebloom without deadheading, but black-eyed Susan must be deadheaded if you want reliable repeat blooming all summer and into fall.
Removing spent blooms also prevents self-seeding. If you don't want the plants to spread throughout the garden, make sure you deadhead plants before the seed heads ripen. Removing the flowers as soon as they are finished blooming also keeps the garden looking neat and tidy. Leaving the Seeds If you decide not to deadhead coneflowers, the seeds will attract birds to the garden. The seeds that birds don't eat fall to the ground and easily sprout to create more plants. Self-seeding can result in a large number of seedlings in the spring, which will start blooming after about two years. The flower center of the coneflower is where seeds develop. After the petals fall off, these seed heads often remain upright in the garden throughout all or part of the winter. This provides winter interest in the garden in the form of dark-colored cone-shaped seed heads, and birds that are attracted to the seeds.
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Miss Chen
2018年07月26日
Miss Chen
Description: This plant is usually a winter annual, although sometimes it is a summer annual. It consists of a rosette of basal leaves up to 9" across, from which one or more flowering stalks develop that are little branched and up to 2½' tall (although individual plants can be much smaller than this). The basal leaves are up to 4½" long and ¾" across; they are elliptic, lanceolate, or oblanceolate, and pinnately lobed. The alternate leaves on the flowering stalks are much smaller in size and widely spaced; they are lanceolate, elliptic or linear in shape, and either smooth or slightly dentate along their margins. The bases of the alternate leaves are either sessile or they clasp their stalks with auriculate (ear-like) lobes. Both the basal and alternate leaves are medium to dark green and mostly hairless, although the lower sides of their central veins are often covered with appressed hairs. The terete stalks are light green to dark reddish purple (usually the latter), and they are usually glabrous above and appressed-hairy below. Each stalk terminates in a raceme of small flowers. These flowers bloom only toward the tip of the raceme and they are short-lived. Each flower is a little less than 1/8" (3 mm.) across and consists of 4 white petals, 4 greenish sepals, a pistil with a single style, and several stamens. Plants that are winter annuals bloom during spring to mid-summer, while summer annuals bloom from mid-summer to fall. The flowers are replaced by seedpods that are obcordoid, somewhat compressed (flattened), and a little less than ¼" long. Each seedpod is divided into 2 cells and contains about 20 seeds. The slender pedicels of the seedpods are about ½-¾" long and ascending. The raceme elongates with maturity and can become up to 1½' long on large plants. The small seeds are yellowish to reddish brown, ovoid-oblongoid in shape, and shiny; they can remain viable in the ground for several years. The root system consists of a taproot. This plant spreads by reseeding itself.
Cultivation: Shepherd's Purse is typically found in full sun, mesic to dry conditions, and almost any kind of soil, including cracks in pavement. The size of this plant varies considerably with the fertility of the soil and availability of moisture. It is somewhat aggressive in reseeding itself. Range & Habitat: Shepherd's Purse is a common plant that occurs in every county of Illinois (see Distribution Map). It was introduced into North America from Europe. Habitats include fields and pastures, areas along railroads and roadsides, gardens and lawns, construction sites, vacant lots, dirt paths, and waste ground. These habitats can be either sandy or non-sandy. Shepherd's Purse is found in highly disturbed areas, often where the soil surface has been exposed.
Faunal Associations: The nectar and pollen of the flowers attract mostly short-tongued bees and flies, including honeybees, Halictid bees, Andrenid bees, Syrphid flies, Tachinid flies, flesh flies (Sarcophagidae), and blow flies (Lucilia spp.). Less often, small butterflies and skippers suck nectar from the flowers (Robertson, 1929). The caterpillars of two butterflies, Anthocharis midea (Falcate Orangetip) and Pontia protodice (Checkered White), feed on Shepherd's Purse (Opler & Krizek, 1984). Other insect feeders include Entomoscelis americana (Red Turnip Beetle), several flea beetle species (Phyllotreta spp.), larvae of Liriomyza trifolii (American Serpentine Leafminer Fly), Holcostethus limbolarius (a stink bug), Myzus cerasi (Black Cherry Aphid), Lipaphis pseudobrassicae (False Cabbage Aphid), and Ceutorhynchus erysimi (a weevil); see Clark et al. (2004), Spencer & Steyskal (1986), Rider (2009), Blackman & Eastop (2013), and Majka et al. (2007). Information about this plant's relationships with vertebrate animals is more limited. White-tailed Deer browse on the leaves and flowering stalks: because the seeds of Shepherd's Purse can pass through the digestive tract of this animal and remain viable, they are spread to new areas (Myers et al., 2004). The Eastern Goldfinch sometimes eats the seeds, while the Prairie Vole (Microtus ochrogaster) feeds on the leaves of this plant to a limited extent (Martin et al., 1951/1961; Cook et al., 2004).
Photographic Location: A garden bed of an abandoned hotel in Urbana, Illinois, and an area along a bike path on the campus of the University of Illinois in the same city. Comments: Shepherd's Purse is an easy plant to identify among members of the Mustard family because of the distinctive shape of its seedpods. This shape apparently resembles the leather purse of shepherds during the Middle Ages. The hairiness of the flowering stalks and the shape of the leaves is rather variable across different populations of plants. Sometimes the basal leaves are deeply lobed, while on other occasions they are shallowly lobed.
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Miss Chen
2018年07月26日
Miss Chen
Description: This plant is a summer annual about 3-9' tall. It is unbranched or little branched. The stout central stem is light green; where new growth occurs, this stem is more or less pubescent, but it becomes less hairy with age. The lower leaves are often opposite, while the upper leaves are alternate. These leaves are palmately compound with 3-9 leaflets (usually there are 5-7 leaflets). On large plants, these leaves can span up to 10" long and across (excluding the petioles), but they are half this size on smaller plants. While the lower leaves have long slender petioles, the upper leaves are nearly sessile. These petioles are more or less pubescent and occasionally reddish green. Each leaflet is narrowly ovate and coarsely serrated along the margins; the middle leaflets are larger in size than the lateral leaflets. The upper surface of each leaflet is dark green and sparsely pubescent. Hemp is dioecious with both male and female plants. The male plants produce both axillary and terminal panicles of male flowers. These panicles are up to 1' long; they have small leafy bracts and pubescent stalks. Each male flower is about 1/8" (3 mm.) across, consisting of 5 sepals, 5 stamens with large anthers, and no petals. The oblong or lanceolate sepals are initially green, but they become cream or pale yellow with maturity. After these flowers have shed their pollen, the foliage of the male plant soon turns yellow and withers away. The female plants produce short axillary spikes of female flowers; these spikes are about 1" long and covered with glandular hairs. Each female flower is about 1/8" (3 mm.) long, consisting of a single sepal, an ovary with two styles, and no petals. The sepal wraps around the ovary, forming a beak at its apex; the 2 styles are exerted from this beak. The surface of the sepal is green and covered with glandular hairs that exude a characteristic odor when they are rubbed. At the base of each female flower, there is a single green bract that is lanceolate and longer than the flower. There are small leaves and other bracts along the spike as well.
The blooming period occurs from mid-summer to early fall and lasts about 1-2 months. Pollination is by agency of the wind. Upon maturity, the female flowers turn brown, but the foliage of female plants remains green until the fall. Each female flower is replaced by an achene containing a single large seed. The root system consists of a branched taproot. This plant often forms colonies at favorable sites. Cultivation: The preference is full sun, moist conditions, and a fertile loamy soil. Mesic conditions and other kinds of soil are also tolerated, but the size of plants will be smaller. Hemp is little bothered by pests and disease. It tolerates occasional flooding.
Range & Habitat: Hemp occurs occasionally in central and northern Illinois, while in the southern portion of the state it is uncommon or absent (see Distribution Map). Hemp is native to central Asia and it was introduced to the United States for agricultural purposes. Habitats include borders of floodplain woodlands, borders of low-lying fields, weedy meadows along rivers, fence rows, and roadside ditches. Occasionally, it is cultivated illegally in backyards and fields. This plant is found primarily in disturbed habitats. Faunal Associations: There is little information about floral-faunal relationships for Hemp. The wind-pollinated flowers don't attract many insect pollinators. Mammalian herbivores avoid browsing on hemp when other plants are available. Photographic Location: A roadside ditch in Champaign, Illinois.
Comments: Hemp has been cultivated in the United States since colonial times. The fibers of the central stem are quite strong; they have been used in making rope, paper, clothing, and other products. The foliage, flowers, and seeds of female plants contain chemicals with medicinal and recreational properties. However, since World War II, it has been illegal in Illinois and other areas of the United States to cultivate hemp. The industrial form of this plant is Cannabis sativa sativa (Hemp), while the medicinal and recreational form is Cannabis sativa indica (Marijuana). It is usually the industrial form of this plant that is encountered in the wild; it has a more robust habit of growth and contains lower levels of chemicals with medicinal and recreational properties. Hemp has a unique appearance and is easy to distinguish from other species of plants. A small specimen of Hemp superficially resembles some Potentilla spp. (Cinquefoils), especially Potentilla recta (Sulfur Cinquefoil), because of the similarity of their palmate leaves. However, the leaflets of Hemp are more elongated and tapered at their tips than Sulfur Cinquefoil. Furthermore, the flowers of Cinquefoils have 5 conspicuous petals that are white or yellow, like many other members of the Rose family, while the flowers of Hemp are devoid of petals.
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Miss Chen
2018年07月26日
Miss Chen
Description: This herbaceous perennial plant is 1½–3' tall and little branched. The central stem is light green to reddish brown, glabrous to slightly hairy, and terete or angular. The alternate leaves are up to 5" long, 2" across, and variable in shape; the lowest leaves are often cordate-oval, while the middle and upper leaves are ovate-lanceolate to lanceolate. All of these leaves have crenate or serrated margins; their upper surfaces are medium to dark green, while their lower surfaces are light green and short-hairy along the veins. The lower and middle leaves have slender petioles, while the upper leaves are more likely to be sessile. Sometimes short leafy stalks develop from the axils of the leaves on the central stem. The central stem terminates in an elongated raceme of flowers up to 1' long. The flowers tend to nod downward along one side of the raceme on short pedicels. At the base of each pedicel, there is a small leafy bract that is linear-lanceolate in shape. Sometimes nodding flowers are produced from the axils of the upper leaves on longer pedicels. Each flower has a bell-shaped blue-violet corolla, 5 green sepals, 5 stamens, and an exerted style with 3 curled stigmas. The corolla is 1–1½" long and half as much across; it has 5 pointed lobes that are recurved. The sepals are linear-lanceolate in shape, widely spreading to recurved, and much smaller in size than the corolla. The style is white or pale purple. The blooming period occurs from mid-summer to early fall and lasts about a month. Each flower is replaced by a globoid seed capsule that contains several small seeds. The root system is rhizomatous. Occasionally, small colonies of plants are produced from the long rhizomes. Cultivation: The preference is full to partial sun, more or less mesic conditions, and a fertile loamy soil.
Range & Habitat: Creeping Bellflower naturalizes occasionally in northern Illinois and uncommonly in central Illinois; it is apparently rare or absent in southern Illinois (see Distribution Map). This species was introduced into North America from Europe as an ornamental plant. Habitats include open woodlands, savannas, thickets, fence rows, edges of yards, roadsides, and waste areas. Creeping Bellflower is often cultivated in gardens because of its showy flowers. Faunal Associations: According to Müller (1873/1883), the flowers of Creeping Bellflower produce both nectar and pollen. Müller observed honeybees, bumblebees, Halictid bees, and other bees visiting the flowers for nectar or pollen in Germany; he also observed a Syrphid fly with a long proboscis (Rhingia sp.) sucking nectar from the flowers. Aside from these observations, further information about floral-faunal relationships for this species are unavailable.
Photographic Location: The photographs were taken at a flower garden in Urbana, Illinois. Comments: Creeping Bellflower has very showy flowers. Among the Eurasian bellflowers that are cultivated, this is the species that most often escapes — in part because it is more commonly cultivated. A species that has naturalized less often in Illinois, Campanula glomerata (Clustered Bellflower), has more erect flowers that are clustered together at the apex each central stem. The flowers of this species have sepals that are longer and wider than those of Creeping Bellflower. The circumboreal Campanula rotundifolia (Harebells) and native Campanulastrum americanum (American Bellflower) are quite distinct from Creeping Bellflower. Harebells has linear leaves along its stems and its bell-shaped flowers are smaller in size (usually less than 1" in length) than those of creeping Bellflower. The flowers of American Bellflower have shallow corollas that are star-shaped with widely spreading lobes; the older scientific name of this latter species is Campanula americana.
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Miss Chen
2018年07月26日
Miss Chen
Description: This plant is a winter annual or biennial that becomes ½–2' tall, branching very little except at the base. The round stems are more or less hairy. The alternate leaves are up to 1½" long and ¼" across. They are oblanceolate, lanceolate-oblong, or oblong-linear, and sessile at the base. The upper surface of each leaf has a single central vein, but radiating side veins are not visible. The leaves are more or less pubescent, although they occasionally have longer white hairs. Their margins are smooth and ciliate. The nearly sessile flowers develop from the axils of the leaves in the upper portion of the stems. They are bunched together while in bloom or at the bud stage, but become more separated from each other as the flowering stems continue to elongate. Each flower is about ¼" long, consisting of a tubular white corolla with 5 small lobes and a hairy green calyx with 5 teeth that are linear-lanceolate. These teeth are about as long as the corolla. There are 5 stamens and a pistil that are inserted within the narrow throat of the corolla. The blooming period can occur from mid-spring to mid-summer and lasts about 2 months. Each flower is replaced by 4 nutlets. A nutlet is truncate at the base and tapers to a blunt round tip at the top. It is broadest a little below the middle, and has a greyish brown surface that is rough and wrinkled. The root system consists of a taproot. This plant spreads by reseeding itself. Cultivation: This adaptable plant can be found in full or partial sun and mesic conditions in fertile loam, clay-loam, or sandy soil. Open areas are preferred where there is a scarcity of taller plants. Close-up of FlowersRange & Habitat: Corn Gromwell is occasional to locally common in most areas of Illinois, except in the NW and SE, where it is uncommon or absent (see Distribution Map). It is adventive in North America and native to Eurasia. Habitats include cropland consisting of winter wheat or rye, fallow fields, vacant lots, grassy areas along roadsides and railroads, and miscellaneous waste areas. This weed occurs primarily in fields or along railroads, but it also appears in run-down areas of cities. Corn Gromwell prefers disturbed areas, and doesn't invade high quality natural sites to any significant degree.
Faunal Associations: Little information is available about floral-faunal relations for this species. According to Muller of 19th century Germany, the flowers of Corn Gromwell have few insect visitors. Occasionally, they attracted White butterflies, bees, and Syrphid flies. Photographic Location: A grassy vacant lot in Urbana, Illinois. Comments: This is a rather inconspicuous plant even while it is blooming. Corn Gromwell resembles many other weeds with small white flowers, but it has a distinguishing characteristic that sets it apart: The teeth of the hairy calyx are unusually long, slender, and conspicuous – about the same length as the flowers. Long after the corolla of a flower has withered away, the teeth of the calyx surround the nutlets on all sides and are much taller than them. Corn Gromwell resembles other members of the Borage family to some extent, including the native Lithospermum latifolium (American Gromwell) and introduced Lithospermum officinale (European Gromwell). However, these latter species have wider leaves with conspicuous side veins. Corn Gromwell is easily distinguished from the many weedy members of the Mustard family because its tubular flowers have 5 petal-like lobes, while the flowers of the latter have only 4 petals. An obsolete scientific name for this plant is Lithospermum arvense.
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Miss Chen
2018年07月26日
Miss Chen
Description: This plant is an annual or biennial about 1-3' tall. Small plants are branched sparingly, while large plants branch abundantly in the upper half. The stems are gray-green or gray-blue, terete, glabrous, and glaucous. Plants that begin growth during the fall will overwinter as low rosettes with basal leaves, while plants that begin growth during the spring bolt upward almost immediately. Both the basal and lower leaves are up to 10" long and 2" across, but they are usually smaller than this. They are oblanceolate in overall shape and strongly pinnatifid with undulate or bluntly dentate margins; their terminal lobes are the largest in size. Both types of leaves have stout petioles. In contrast, the middle to upper leaves are smaller in size, lanceolate-oblong in shape, with margins that are smooth or bluntly dentate. These latter leaves have bases that usually clasp their stems, although some of them may be sessile. Like the stems, these various leaves are grey-green or blue-green, glaucous, and usually glabrous – occasionally the basal leaves have short bristly hairs. The lower, middle, and upper leaves are alternate. The upper stems terminate in racemes of bright yellow flowers. The flowers bloom toward the apex of each raceme, while the seedpods develop below. Each flower is 1/3–1/2" (8-12 mm.) across, consisting of 4 yellow petals, 4 green to yellow sepals, several stamens, and a pistil with a single style. The sepals are narrowly lanceolate and hairless. The blooming period can occur anytime between late spring to early fall; it usually lasts about 1 month for a small colony of plants. Each flower is replaced by an ascending cylindrical seedpod (silique) that is 1¼–2¼" long at maturity and hairless. Each seedpod terminates in a seedless beak that is about one-fourth its entire length. At the base of each seedpod, there is a stout hairless pedicel about ½" long that is widely spreading to ascending. Each seedpod divides into 2 valves to release its small globoid seeds. The root system consists of a taproot. This plant reproduces by reseeding itself. Cultivation: Rape Mustard prefers full sunlight, moist to dry conditions, and a neutral to alkaline soil containing loam, clay-loam, or gravelly material. The size of individual plants varies greatly according to moisture conditions and soil fertility. Range & Habitat: Rape Mustard is occasional in most areas of Illinois (see Distribution Map). It is native to Eurasia. Typical habitats include cropland, weedy fields, roadsides, gravelly areas along railroads, and waste areas. This plant is usually found in areas with a history of disturbance where there is scant ground vegetation.
Faunal Associations: The nectar of the flowers attracts small bees and White butterflies (Pieridae); some bees may collect pollen from the flowers as well. The caterpillars of the butterflies Pieris napi (Mustard White), Pieris rapae (Cabbage White), and Pontia protodice (Checkered White) feed on Brassica spp. (Mustards), as do the caterpillars of the moths Evergestis pallidata (Purple-Backed Cabbageworm) and Plutella xylostella (Diamondback Moth). Several species of flea beetles (primarily Phyllotreta spp.), Murgantia histrionica (Harlequin Bug), and Adelphocoris superbus (Meadow Plant Bug) also feed on the foliage of these plants. The oily seeds of Rape Mustard and similar species are eaten by the Mourning Dove and Ring-Necked Pheasant, and the mild-tasting foliage can be eaten in limited amounts by livestock and other mammalian herbivores. Photographic Location: A gravelly area along a railroad in Savoy, Illinois. Comments: This is another weedy mustard species from Eurasia. It should not be confused with the agricultural crop, Oilseed Rape (or Canola), which is Brassica napus oleifera, or one of the cultivated vegetables. Rape Mustard has several common names, including Field Mustard and Birdseed Rape. In general, Rape Mustard can be distinguished from other Brassica spp. (Mustards) by its glaucous gray-blue or gray-green foliage and its clasping alternate leaves. A similar species, Brassica oleracea (Wild Cabbage), shares these characteristics, but this latter species has larger flowers (exceeding ½" across) and it is quite rare in Illinois. Oilseed Rape has foliage that is more green than either Rape Mustard or Wild Cabbage, and its foliage isn't glaucous.
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Miss Chen
2018年07月25日
Miss Chen
Description: This plant is a summer annual that becomes 2-8' tall, branching occasionally. The stems are usually glabrous and glaucous; sometimes they have scattered stiff hairs toward the base. The alternate leaves are up to 10" long and 3" across, becoming smaller as they ascend the stems. The lower leaves are pinnately lobed and obovate in outline, tapering to a long and rather stout petiole. The terminal lobe is much larger than the lateral lobes. The upper surface of a lower leaf is often bristly with scattered hairs that are stiff, short, and white. The lower surface is usually glabrous, except for a few hairs along the central vein. The upper leaves are often lanceolate, broadly elliptic, or some other odd shape; they have 1-2 lobes or none. The upper stems terminate in narrow racemes of yellow flowers; these racemes are ½–2' long when fully mature. Each flower is up to 1/3" (8 mm.) across, consisting of 4 yellow petals, 4 sepals, several stamens, and a pistil. The sepals are initially green, but become yellow while the flower blooms. The petals are well-rounded toward their tips. The blooming period occurs primarily during the summer and lasts about 1-2 months. A few plants may bloom during the fall. Each flower is replaced by a slender silique that becomes appressed against the stalk of the raceme as it matures. This silique is about 2/3" (17 mm.) long, tapering to a conical beak. The petiole of the silique (or flower) is about 1/3" (8 mm.) long. The seeds within this silique are dark brown or black. Both the seeds and the foliage have a pungent taste. The root system consists of a taproot. This plant spreads by reseeding itself.
Cultivation: This plant often occurs in full or partial sun, fertile soil, and mesic conditions. On less fertile ground, it is smaller in size. During hot sunny weather the leaves have a tendency to wilt, but they quickly recover by nightfall. Sometimes this plant becomes lanky and flops sideways. Range & Habitat: The non-native Black Mustard is a common plant in central and northern Illinois, but it is less common or absent in southern Illinois (see Distribution Map). Habitats include weedy meadows, thickets, areas along railroads and roadsides, fallow fields, vacant lots, and miscellaneous waste places. Disturbed areas are preferred; Black Mustard doesn't invade high quality natural areas to any significant degree. It is native to Eurasia.
Faunal Associations: The nectar and pollen of the flowers attract primarily small bees and flower flies; less common visitors include White butterflies and wasps. The foliage is occasionally eaten by the caterpillars of various White butterflies, including Pieris rapae (Cabbage White) and Pontia protodice (Checkered White). The pungent foliage is usually avoided by mammalian herbivores; it is somewhat toxic to them. Photographic Location: Along a railroad in a partially shaded area in Urbana, Illinois.
Comments: If you see a lanky mustard plant with narrow stalks of yellow flowers that is over your head, there's a good chance that it's Black Mustard. The seeds of Black Mustard are often used in the table condiment, hot mustard. Among the many Brassica spp. and Synapis spp. (Mustards), Black Mustard can be identified by considering the following characteristics: 1) It is often quite tall, 2) the slender siliques are appressed together near the stalk of each raceme, 3) the siliques are less than ¾" long and they have distinct beaks, 4) the leaves narrowly clasp the stems, 5) the terminal lobes of the lower leaves are much larger than the lateral lobes, and 6) the lower leaves often have short stiff hairs and feel bristly to the touch. Other mustards are often lacking one or more of these features.
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