动态第175页 - 绿手指 - 养花技巧、花生病了怎么办、花园打理和设计

2018年06月17日

Description: This herbaceous vine is a summer annual up to several feet long that branches occasionally to abundantly. It sprawls across other vegetation that it parasitizes, extracting water and nutrients through clinging suckers (haustoria). Sometimes this vine is so robust that it forms a dense maze of stems that partially obscures the vegetation underneath. The stems are orange, terete, glabrous, and occasionally warty. The alternate leaves are reduced to minute scales or they are absent. Small clusters of flowers develop at intervals along the stems on greenish yellow peduncles and pedicels that are glabrous. The pedicels of the flowers are very short (less than 1 mm. in length). Each flower spans about 3 mm. across, consisting of a short-tubular calyx with 4 obtuse lobes, a short-tubular corolla with 4 ascending to erect lobes, 4 stamens, and a pistil with a pair of divergent styles. Less commonly, a flower may have 5 calyx lobes, 5 corolla lobes, and 5 stamens. The calyx is light green or pale yellow and glabrous, while the corolla is white and its lobes are ovate with blunt tips. The lobes of the calyx extend to about the sinuses of the corolla or a little less. Inside the corolla at the base of the stamens, there are fringed floral scales (requires at least a 10x hand lens to see). The blooming period occurs from mid-summer to early fall, lasting about 1½ months. The flowers may be slightly fragrant, and they are self-fertile. The flowers are replaced by globoid seed capsules spanning 3-5 mm. across; they are surrounded by their persistent calyces and the withered remnants of their corollas. Immature seed capsules are light green or pale yellowish green, but they become brown at maturity. Each capsule has 2 cells and contains up to 2 seeds per cell. The seeds are 1.0-1.5 mm. in length and ovoid in shape. While a young seedling has a rudimentary root system, it soon withers away after the seedling attaches itself to a suitable host plant. Without a host plant, the seedling soon dies as it lacks chlorophyll.Stems & Buds [图片]Cultivation: This parasitic vine is typically found in moist to wet open areas where the soil contains abundant organic material and possibly some silt or sand. Favored host plants are smartweeds (Persicaria spp.), but many other species of plants are also parasitized. During certain times of the year, the host plants may be found in shallow standing water. Smartweed Dodder can spread aggressively and seriously weaken its host plants. The small seeds of dodders (Cuscuta spp.) can remain viable for 5-7 years (Georgia, 1913). Range & Habitat: The native Smartweed Dodder is scattered across most areas of Illinois, except possibly the NW section of the state (see Distribution Map). In those areas where this species occurs, it is uncommon to occasional. Habitats include moist to wet prairies, soggy thickets along rivers, fens, sandy marshes, and other wet places. Faunal Associations: The floral nectar of dodders (Cuscuta spp.) attracts Halictid bees (Lasioglossum spp.), plasterer bees (Colletes spp.), and other small bees (Robertson, 1929). According to Müller (1873/1883), the flowers can attract moths. According to Georgia (1913), the seeds of these parasitic vines can pass through the digestive tracts of grazing animals (e.g., cattle, horses, etc.) and remain viable. Thus, these animals may help to spread these vines into new areas. Photographic Location: Cowle's Bog (actually, a fen) at the Indiana Dunes National Lakeshore in NW Indiana. Comments: Because of its bright orange stems, this is a conspicuous vine, especially when it develops into a sprawling mass that resembles a large pile of abandoned tangled string. This is quite a sight to behold. Smartweed Dodder can be distinguished from most species of dodders (Cuscuta spp.) by its 4-parted flowers (4 calyx lobes, 4 corolla lobes, and 4 stamens). Two exceptions are Hazel Dodder (Cuscuta coryli) and Buttonbush Dodder (Cuscuta cephalanthi), which also have 4-parted flowers. These latter two species have yellow stems, rather than bright orange stems. Compared to Smartweed Dodder, the corolla lobes of Hazel Dodder are more erect with acute and incurved tips, while the corolla lobes of Buttonbush Dodder are widely spreading. Aside from these species, other dodders in Illinois have 5-parted flowers (5 calyx lobes, 5 corolla lobes, and 5 stamens).

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Miss Chen

2018年06月17日

Buttonbush Dodder on a Host PlantDescription: This herbaceous parasitic vine is a summer annual that is several feet along. It clings to adjacent vegetation using suckers (haustoria) on its stems. Lacking chlorophyll and a significant root system, this vine is dependent on its host plants for water and nutrients. The stems are usually pale yellow, sometimes becoming pale orange with age; they are glabrous and terete. Alternate leaves along the stems are reduced to tiny scales, or they are absent altogether. Small clusters of nearly sessile flowers occur at intervals along the stems. The peduncles and pedicels of these flowers are pale yellow to pale orange and glabrous. Each flower spans about 3 mm. (1/8" across), consisting of a white corolla with 4 lobes, a light green calyx with 4 lobes, 4 stamens, and an ovary with a pair of divergent styles. Less often, a flower may have a corolla with 5 lobes, a calyx with 5 lobes, and 5 stamens. The lobes of the corolla are deltate-ovate in shape and ascending to widely spreading. The calyx is glabrous with rounded lobes; it is shorter than the corolla. Both the corolla and calyx are short-tubular and bell-shaped (campanulate). At the base of the stamens within the corolla, are fringed scales that require at least a 10x hand lens to see. There are no floral bracts underneath the flowers. The blooming period occurs from mid-summer to early fall, lasting about 1½ months. There may be a mild floral fragrance. In the absence of insect pollinators, the flowers are self-fertile; they are replaced by globoid seed capsules spanning 3-5 mm. across. The glabrous seed capsules are surrounded by the withered remains of their corollas; they are initially light green, but turn brown at maturity. Each capsule is 2-celled, and each cell contains 2 seeds. The capsules eventually split open to release their seeds. The seeds are about 1.5 mm. long (or slightly more), ovoid in shape, and slightly compressed. There is a rudimentary root system at the seedling stage, but this is abandoned shortly after a suitable host plant has been found. If no host plant is found, the seedling dies within a few days. Cultivation: This vine is typically found in wet to moist areas that are exposed to sun or partial sun. It cannot survive without a suitable host plant, although apparently many species of moisture-loving plants and shrubs can serve this purpose. Examples of suitable host plants include buttonbush (Cephalanthus occidentalis), water willow (Justicia americana), false nettle (Boehmeria cylindrica), asters (Aster spp.), goldenrods (Solidago spp.), bugleweed (Lycopus spp.), and even horsetails (Equisetum spp.). Soil type depends on the preferences of host plants, but can consist of sand, silt, loam, or muck. This vine can significantly weaken any host plant that it comes in contact with. [图片]Range & Habitat: The native Buttonbush Dodder is scattered throughout Illinois, where it is uncommon to occasional (see Distribution Map). Habitats include floodplain woodlands, swamps, soggy thickets along rivers, marshes, and wet prairies. This vine occurs in both sandy and non-sandy wetlands. Faunal Associations: Robertson (1929) observed a small Halictid bee, Lasioglossum coriaceus, sucking nectar from the flowers of Buttonbush Dodder. Other small bees also visit the flowers for nectar, and possibly some moths (Müller, 1873/1883). According to Georgia (1913), the seeds of dodders can pass through the digestive tracts of grazing animals (e.g., cattle & horses) and remain viable. Thus, these animals may help to distribute these vines into new areas. [图片]Photographic Location: A sandy marsh at the Heron Boardwalk in Vermilion County, Illinois. Comments: Buttonbush Dodder has a fairly typical appearance for the parasitic vines of this genus, although it is somewhat unusual in having 4-parted flowers (4-lobed corollas, 4-lobed calyces, and 4 stamens), rather than 5-parted flowers (5-lobed corollas, 5-lobed calyces, 5 stamens). Unlike other dodder species (Cuscuta spp.) with 4-parted flowers, the corolla lobes of Buttonbush Dodder usually spread outward rather than remain erect. Thus, it is a fairly easy species to identify during the blooming period. Some taxonomists have placed dodder species in the Morning Glory family (Convolvulaceae).

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Miss Chen

2018年06月17日

Description: This perennial plant is 1-2½' tall, branching occasionally to abundantly. The stems are light green, terete, and appressed-pubescent. The opposite leaves are up to 3" long and 2" across; they have short slender petioles. The leaf blades are oval-cordate, oval, or ovate in shape, while their margins are dentate or dentate-crenate. The upper blade surface is light green and glabrous with a conspicuous network of veins. The upper stems terminate in flat-topped clusters of flowerheads. Each cluster of flowerheads spans about 1-3" across. Each flowerhead has about 40-50 disk florets that are pink, lavender, or blue. Each floret has a tiny tubular corolla with 5 spreading lobes and a strongly exerted style that is divided into two filiform parts. Around the base of each flowerhead, there are several floral bracts (phyllaries) that are arranged in 1-2 series; they are light green and linear in shape. The branches underneath each flowerhead cluster are light green and terete. The blooming period occurs from mid-summer to early autumn, lasting about 1-2 months. There is no noticeable floral scent. Afterwards, the florets are replaced by achenes with small tufts of hair; they are distributed by the wind. The root system is highly rhizomatous; this plant readily forms colonies. Cultivation: The preference is full sun to light shade, moist conditions, and soil containing loam or silt. There should be sufficient organic material in the soil to retain moisture. This plant can spread aggressively in moist open ground, otherwise it presents few problems. Drought tolerance is poor. Propagation is by seed or division of the rhizomes. [图片]Range & Distribution: The native Mistflower occurs in the southern half of Illinois and the Chicago area (see Distribution Map). It is fairly common in southern Illinois, but uncommon or absent elsewhere. This plant was introduced into the Chicago area. Some local populations in the wild are probably the result of seeds or plants that have escaped cultivation. Habitats include river-bottom prairies, moist open woodlands, gravelly seeps, borders of lakes and rivers, moist meadows in wooded areas, bases of bluffs, and ditches. This plant usually occurs in poorly drained areas and near sources of water. Faunal Associations: The flowers attract long-tongued bees, butterflies, and skippers. Other occasional visitors include short-tongued bees, various flies, moths, and beetles. These insects seek nectar primarily, although the bees often collect pollen. Insects that feed on Eupatorium spp. (Bonesets) may also feed on Mistflower. Insect feeders of this group of plants include the caterpillars of such moths as Haploa clymene (Clymene Moth; eats foliage), Phragmatobia lineata (Lined Ruby Tiger Moth; eats foliage), Carmenta bassiformis (Eupatorium Borer Moth; bores into roots), and Schinia trifascia (Three-Lined Flower Moth; eats florets & developing seeds). Mammalian herbivores rarely consume Mistflower because of its bitter foliage. [图片]Photographic Location: The photograph was taken along a drainage canal at Kaufman Lake Park in Champaign, Illinois. Comments: Mistflower has attractive delicate flowers that are colored in pastel shades of pink, lavender, or blue. For this reason, it is often grown in flower gardens. This plant is closely related to the white-flowered Bonesets (Eupatorium spp.), and sometimes it is still referred to as Eupatorium coelestinum. Mistflower can be distinguished from the Bonesets primarily by its colorful flowers, relatively short stature, and broad opposite leaves that are heavily veined. While species of Joe-Pye Weed (Eupatoriadelphus spp.) have similar colorful flowers, they are taller plants with whorled leaves. All of these species are similar in that their flowerheads consist entirely of disk florets.

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Miss Chen

2018年06月16日

Description: This perennial wildflower is 1½–6' tall, branching occasionally along the upper half of its length. The rather stout stems are light green to reddish purple (often the latter), terete to slightly grooved, and evenly covered with stiff spreading hairs. The alternate leaves are up to 6" long and 1¾" across, becoming gradually smaller along the upper half of each plant; they are narrowly lanceolate to lanceolate with poorly defined remote teeth along their margins. The leaves are yellowish green, medium green, or purple (sometimes the latter color during the fall); they are usually glabrous, except for some hairs along the central veins of their lower sides. Most leaves clasp the stems, although some of the smaller upper leaves are sessile. The central stem terminates in a panicle of flowerheads; some lateral stems may produce smaller panicles of flowerheads. The branches of each panicle are ascending and usually hairy. Along these branches, there are linear-lanceolate leafy bracts up to 1" long. The outer branches terminate in flowerheads about ¾–1¼" across, consisting of 30-50 ray florets and a similar number of central disk florets. The petal-like rays are usually lavender, pale blue-violet, or purple (less often white); they are widely spreading and very slender. The tubular disk florets are 5-lobed; they are initially yellow, but later become dull red. At the base of each flowerhead, there are several overlapping bracts that are linear in shape, green, and hairless; they are rather loosely assembled around the base of the flowerhead and slightly spreading. The blooming period occurs from late summer into the fall and lasts about 2 months. Both disk and ray florets are fertile. The florets are replaced by bullet-shaped achenes about 1.5 mm. long that have small tufts of white hair; they are distributed by the wind. The root system is fibrous and short-rhizomatous, sometimes forming a small caudex on older plants. Cultivation: The preference is full or partial sun and wet to moist conditions. The soil should contain some organic material to retain moisture and it should be reasonably fertile. Sometimes, the leaves become diseased and rather battered in appearance by the end of the year; the lower leaves may turn brown and fall off in response to droughty conditions. The size of individual plants can be highly variable. Range & Habitat: The native Swamp Aster is occasional in the northern half of Illinois, while in the southern half of the state it is uncommon or absent. Habitats include soggy thickets along streams, open swamps, fens and calcareous seeps, sedge meadows, and other wetlands. Swamp Aster is often found in higher quality wetlands where the native flora is still intact. It is primarily a boreal species that is found around the Great Lakes and other cool areas. Faunal Associations: The nectar and pollen of the flowerheads attract a wide variety of insects, including honeybees, bumblebees, other miscellaneous bees, various wasps, bee flies and other miscellaneous flies, and various butterflies, skippers, and moths. The oligolectic bees, Andrena asteris and Andrena hirticincta, suck nectar and collect pollen from the flowerheads of Swamp Aster. Other insects feed on the foliage, suck plant juices, bore through the stalks and roots, or gnaw on the flowers and developing seeds of Symphyotrichum spp. (asters). These species include Microrhopala xerene and other leaf beetles, several aphids (mostly Uroleucon spp.), the stinkbug Trichopepla semivittata, the leafhopper Macrosteles quadrilineatus, the plant bug Plagiognathus cuneatus, Poecilocapsus lineatus (Four-Lined Plant Bug), Lygus lineolaris (Tarnished Plant Bug), and the larvae of Calycomyza humeralis (Aster Leafminer Fly). In addition to these insects, a large number of moth caterpillars feed on asters (see the Moth Table for a listing of these species), as do the caterpillars of the butterflies Chlosyne nycteis (Silvery Checkerspot) and Phyciodes tharos (Pearl Crescent). Among vertebrate animals, the Wild Turkey eats the seeds and leaves occasionally, while the White-Tailed Deer and Cottontail Rabbit browse on the foliage. Photographic Location: A low area along a pond at Weaver Park in Urbana, Illinois. [图片]Comments: Except for Symphyotrichum novae-angliae (New England Aster), Swamp Aster has larger flowerheads than other Symphyotrichum spp. (asters) in Illinois and its flowerheads usually have more rays (about 30-50). It is a pretty hefty plant that is about as tall as New England Aster. This latter species has glandular hairs along its stems and its leaves are less shiny than those of Swamp Aster. Swamp Aster is divided into two varieties or subspecies: the typical variety/subspecies has evenly hairy purple stems, while variety/subspecies firmus (or lucidulous) has light green stems that are either hairless or the hairs are arranged in lines; sometimes the color of the stems is not reliable in making this distinction. The rhizomes of the typical variety/subspecies are supposed to be short, while the rhizomes of variety/subspecies firmus (or lucidulous) are supposed to be long. Some authors (e.g., Mohlenbrock, 2014), divide Swamp Aster into two separate species: Symphyotrichum puniceum and Symphyotrichum firmum. They have a similar distribution and are about equally common in Illinois. The preceding descriptive information and photos apply to Symphyotrichum puniceum puniceum. A scientific synonym of Swamp Aster is Aster puniceus.

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Miss Chen

2018年06月16日

Description: This perennial wildflower is an emergent aquatic about 3-8' tall, consisting of a small cluster of 2-5 deciduous basal leaves and a tall flowering stalk. The blades of basal leaves are 6-21" long and about one-third as much across; they are lanceolate to ovate in shape and smooth (entire) along their margins. The upper blade surface is pale green and glabrous, while the lower blade surface is whitish green and glaucous. Fine hairs are often present along the base, central veins, and margins of the blade underside. The erect petioles of basal leaves are 1½-3' long; they develop from a basal sheath. The petioles and basal sheath remain buoyant in water as a result of internal air cavities. The ascending blades diverge from their sheathed petioles at an angle. Leaf venation is pinnate with lateral veins that are parallel, curving toward the blade tips as they approach the margins. An erect or ascending stalk about 4-8' tall terminates in a floral panicle about 4-18" long with a leafy bract at its base that is early-deciduous. The lateral branches of the panicle are ascending to drooping and slightly zigzag; they are reddish brown, but covered with a white powdery bloom. The whitish purple flowers develop in pairs along these lateral branches, where they bloom in succession. Adjacent pairs of flowers are spaced about 3 mm. from each other. A pair of large floral bracts are located at the base of each pair of flowers; these bracts are powdery white. Each flower is about 10-17 mm. long, consisting of 3 sepals, 3 petals, an ovary with a single style, a single fertile stamen, and 3 staminodia (sterile stamens). The membranous sepals are about 2 mm. long and insignificant. The petals join together at the base, forming a short corolla tube. The fertile stamen and staminodia are highly modified petaloid structures; they are purple to whitish purple and showy. The hooded staminodium has a pair of trigger-like appendages that, when they are depressed, release an elastic style with a cup-shaped stigma, enabling cross-pollination of the flower. The blooming period occurs from mid- to late summer, lasting about 1 month (in Illinois). Afterwards, fertile flowers areDistribution Map replaced by globoid-ovoid seed capsules. Each capsule contains a single large seed about 8 mm. long that is dark brown, globoid-ovoid in shape, and smooth. The root system is rhizomatous, from which clonal colonies of plants are produced. Cultivation: The preference is full sun, wet ground with up to 1½' of water, and muddy or clay soil with organic matter. This wildflower can be propagated by either its seeds or division of its rhizomes. It is hardy to Zone 5 or Zone 6 if the rhizomes are protected by standing water during the winter and a northern ecotype is selected. Range & Habitat: The native Powdery Thalia has been found in Alexander County at the southern tip of Illinois, where it is rare and state-listed as 'endangered.' Elsewhere in the state, it is absent. Illinois lies along the northern range limit of this species; it is more common in areas further south. Habitats include margins of ponds, marshes, swamps, and wet ditches along roads. Powdery Thalia is cultivated occasionally as an ornamental plant for ponds and wetland gardens. Faunal Associations: The unusual flowers rely on explosive secondary pollination. The anther of the fertile stamen drops pollen grains onto a depression of the elastic style (immediately behind its stigma) during evening hours. The following morning, flower-visiting insects can trigger an appendage of the hooded staminodium, releasing the elastic style with its load of pollen. This area of the style strikes near the insect's head. The flowers of Powdery Thalia are cross-pollinated by nectar-seeking carpenter bees (Xylocopa virginica) and possibly large bumblebees (Bombus spp.); flies and other smaller insects often become trapped by the elastic styles of the flowers and die. Such floral visitors as large butterflies and hummingbirds are able to feed on nectar without triggering the explosive mechanism of pollen delivery; they are considered nectar thieves. The caterpillars of Calpodes ethlius (Brazilian Skipper) feed on the leaves of Powdery Thalia; they are leaf-rollers. This skipper does not successfully overwinter in Illinois, but it migrates northward and can reach the state during the summer. The large seeds are eaten by the Mallard, Lesser Scaup, and probably other ducks (Martin & Uhler, 1939). [图片]Photographic Location: A botanical garden in Chicago, Illinois. The photographs were taken by Rita Ryan (Copyright © 2012). Comments: Powdery Thalia is the only species in the Arrowroot family that is native to Illinois. It is a tropical-looking plant with large showy leaves and unusual purple flowers. The only other species of this genus that is native to the United States, Thalia geniculata (Alligator Flag), is found primarily in areas along the Gulf coast. It differs from Powdery Thalia by the lack of white powdery bloom on its foliage and flowers. In addition, the lateral floral branches of Alligator Flag are more zigzag than those of Powdery Thalia because adjacent pairs of its flowers are more widely spaced (at least 5 mm. apart).

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Miss Chen

2018年06月16日

Description: This is a herbaceous vine about 2-6' long that is either unbranched or branched occasionally. It either sprawls across the ground or climbs adjacent vegetation. This vine is either a summer annual or perennial (there are differing descriptions in this regard). The stems are light green, glabrous, angular, and prickly along their angles. The prickles are retrorse (curve downward) and about 1 mm. in length. Alternate leaves occur at intervals along the stems. These leaves are 2½-6" long and 2-4" across; they are hastate to broadly hastate in shape and smooth along their margins. The basal lobes of these leaves are triangular-shaped and divergent. Leaf tips taper to an acute point, while leaf bases are indented. The upper leaf surfaces are medium green and glabrous to sparsely short-pubescent, while the lower leaf surfaces are light green and sparsely to moderately covered with short stellate hairs. Small retrorse prickles occur along the major veins on the leaf undersides. Petioles are ½-4" long (becoming shorter as they approach the terminal points of stems), light green, and plano-convex (flat or slightly concave along their upper sides, convex along their lower sides). There are also retrorse prickles along the lower sides of the petioles. At the bases of petioles, there are ochrea (membranous sheaths) up to ½" long that wrap around the stems. These ochrea have rings of retrorse prickles around their bases, and their upper margins are often ciliate. Both axillary and terminal inflorescences are produced on peduncles about 1-4" long. These inflorescences are variable, consisting of dense head-like racemes, interrupted racemes that are sparsely flowered, and/or sparsely branched panicles consisting of 2 or more racemes. Sometimes only a single flower is produced, rather than a raceme of flowers. Each flower is about ¼" (5-6 mm.) long, consisting of 4-5 tepals, an ovary with a pair of styles, and 6 stamens (less often 8 stamens). The tepals can be reddish white, pinkish white, greenish white, or white; they are broadly elliptic in shape. The peduncles are light green, glandular-hairy, and sometimes prickly below. The blooming period occurs from mid-summer into the fall, lasting about 1-3 months. Afterwards, the flowers are replaced by seeds that are 3.5-4.0 mm. long and a little less across at maturity; they are ovoid, slightly flattened, biconvex (rounded on both sides), dark brown, and shiny. This vine can spread vegetatively by forming rootlets when the nodes of stems touch moist ground. Cultivation: This vine prefers partial sun, wet to consistently moist conditions, and soil containing some sand and decaying organic matter (silt and other soil types may also be acceptable). Most growth and development occurs during the summer. [图片]Range & Habitat: Halberd-Leaved Tearthumb is native to only a few counties in the eastern half of Illinois (see Distribution Map). It is state-listed as 'endangered.' This vine is probably extirpated from Macon and McHenry counties because their specimens were collected prior to 1875 (Mohlenbrock, 2002). Illinois lies along the western-range limit of this species; it is more common further to the east. Habitats include bottomland woodlands, swamps, seeps and springs, low areas along ponds, and sloughs with fairly consistent moisture levels. Many of the preceding habitats, where this vine occurs, are often sandy and partly shady. Halberd-Leaved Tearthumb is usually found in high quality natural areas. Faunal Associations: Little is known about the floral-faunal relationships of this vine specifically, although they are probably similar to those of smartweeds (Persicaria spp.). The flowers are probably pollinated by small bees, various flies, small butterflies, and wasps. Insects that feed on various parts of smartweeds include the caterpillars of butterflies and moths, flea beetles, aphids, and stink bugs. In particular, caterpillars of the butterflies Lycaena helloides (Purplish Copper) and Lycaena hyllus (Bronze Copper) feed on the foliage of smartweeds. Such wetland birds as the Mallard and other dabbling ducks, some rails, and granivorous songbirds (e.g., Bobolink, Swamp Sparrow, Redwing Blackbird) eat the seeds. Because Halberd-Leaved Tearthumb can form a tangle of leaves and prickly stems, it is able to provide some protective cover to various kinds of wetland wildlife. [图片]Photographic Location: An open sandy swamp at the Indiana Dunes State Park in NW Indiana. Comments: Halberd-Leaved Tearthumb can be distinguished from other similar vines in Illinois by its prickly stems and hastate leaves (shaped like Medieval halberds). Its closest relative in the state, the more common Tracaulon sagittatum (Arrow-Leaved Tearthumb), differs by having sagittate leaves (shaped like arrowheads), ochrea that lack rings of prickles, and seeds that are bluntly 3-angled (rather than biconvex and two-sided). Many contemporary authorities prefer to merge Tearthumb vines (Tracaulon spp.) with the smartweeds (Persicaria spp.). As a result, they refer to Halberd-Leaved Tearthumb as Persicaria arifolia. Another scientific name for this species, Polygonum arifolium, also appears in older sources of information. The classification that is used here follows Mohlenbrock (2002) and Mohlenbrock (2010). The leaves of Halberd-Leaved Tearthumb superficially resemble the leaves of other species, both wild and cultivated, in the Arum family (Araceae). This similarity of form is the source of the scientific name for this species (arifolium).

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Miss Chen

2018年06月16日

Description: This herbaceous plant is an annual vine about 3-6' long that branches occasionally. It often climbs over adjacent vegetation (or itself), creating a tangle of stems and leaves. The stems are light green, yellowish green, or red; they are strongly angular and prickly. The well-developed prickles are curved with their tips pointing downward. Alternate leaves are widely spaced along the stems. The leaf blades are up to 4" long and 1" across; they are narrowly sagittate to sagittate in shape and their margins are smooth and slightly ciliate with stiff hairs. The upper blade surfaces are medium green and hairless, while their lower surfaces are pale green and slightly prickly along their central veins. The leaves are sessile or they have petioles up to 1" long. Near the base of each petiole, there is an oblique membranous sheath (ochrea) that wraps around the stem; this sheath is largely devoid of hairs and prickles. Both terminal and axillary flowers are produced on short spike-like racemes. The racemes are globoid or ovoid-globoid in shape and up to ½" long; they are produced individually or in pairs on long naked peduncles up to 6" long. The flowers are densely arranged along each raceme. Individual flowers are about 1/8" (3 mm.) long, consisting of 5 white to pink tepals, 8 short stamens, and an ovary with a tripartite style. At the base of each raceme, there is a pair of small green bracts. Similarly, at the base of each flower,Distribution Map there is a pair of tiny bracts that are greenish yellow and ovate. The blooming period occurs from mid-summer into the fall and lasts about 2-3 months. Each flower is replaced by a single dark seed that is about 3 mm. long, ovoid, and bluntly 3-angled. This herbaceous vine can form rootlets where the stems are decumbent on moist open ground. Cultivation: The preference is partial sun, wet to moist conditions, and soil containing silty loam, sand, gravel, or peat moss. Most growth and development occurs during the summer. Temporary flooding is tolerated. Range & Habitat: Arrow-Leaved Tearthumb is occasional throughout Illinois, where it is native. In addition to its distribution in eastern North America, this herbaceous vine also occurs in China. It is found in a variety of wetland habitats, including marshes, swamps, recently burned bogs, gravelly seeps, low areas along springs, and soggy thickets. The marshes, swamps, and soggy thickets where this vine occurs are sometimes sandy and sometimes non-sandy. Faunal Associations: The floral-faunal relationships of Arrow-Leaved Tearthumb are similar to Persicaria spp. (Smartweeds). The nectar and pollen of the flowers attract primarily small bees, wasps, and flies. The leaves are eaten by the caterpillars of the butterflies Lycaena helloides (Purplish Copper) and Lycaena hyllus (Bronze Copper), while the flowers and developing seeds are eaten by the caterpillars of the butterfly Strymon melinus (Gray Hairstreak). Other insects that feed on this plant include flea beetles, aphids, stinkbugs, and the caterpillars of several moths. Various species of birds that occur in wetlands eat the seeds; these include Mallards and other dappling ducks, some rails, and granivorous songbirds (e.g., Bobolink, Swamp Sparrow, Redwing Blackbird). Because it often forms dense tangles of prickly stems and leaves, Tearthumb provides protective cover for various kinds of wildlife. Photographic Location: A soggy sandy thicket at the Iroquois County Conservation Area in Illinois. [图片]Comments: Arrow-Leaved Tearthumb is very similar to the more common Persicaria spp. (Smartweeds), except it is a sprawling vine rather than an erect plant. Because of its prickly stems, arrowhead-shaped leaves, and short dense heads of flowers, it is very easy to identify. Another native species that is a sprawling vine, Tracaulon arifolium (Hastate-Leaved Tearthumb), is very similar in appearance, except its leaves are hastate with spreading basal lobes. This uncommon vine also differs from Arrow-Leaved Tearthumb by its more flattened seeds and bifurcated styles (divided into two parts, rather than three). A scientific synonym of Arrow-Leaved Tearthumb is Polygonum sagittatum.

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Miss Chen

2018年06月16日

Description: This herbaceous perennial plant forms a small tuft of ascending to arching basal leaves about 4-12" (10-30 cm.) long. Individual basal leaves are about 1 mm. across, medium green, terete, and hairless (or nearly so). One or two erect floral stalks about 8-16" (20-40 cm.) long develop from the tuft of leaves; these stalks are about 1.5 mm. across, reddish brown, terete, and hairless. The foliage is reportedly aromatic when crushed. Each stalk has a narrow raceme of flowers about 3-10" (7.5-25 cm.) long; these flowers alternate along the stalk and they are sparsely distributed. Each flower is about 2 mm. across, consisting of 3 purplish green petals, 3 purplish green sepals, 3 fertile green pistils that are joined together, and 6 inconspicuous stamens. The outer sepals are orbicular-ovate in shape, while the inner petals have a flattened-pyriform shape. The stigmas of the pistils are white and feathery (plumose). The slender pedicels of the flowers are 2-10 mm. long, ascending to erect, reddish brown, and hairless. The blooming period occurs during the summer and early autumn, lasting about 1-2 months for a large colony of plants. The flowers are cross-pollinated by the wind. Afterwards, the pistils develop into 3-celled fruits (schizocarps) about 7-9 mm. long and 1 mm. across. These fruits are narrowly oblongoid-oblanceoloid in shape and 3-angled; they are initially green, but later become brown. At maturity, these fruits divide longitudinally into 3 narrow sections, beginning at the bottom. The central axis of each fruit is 3-winged; there are 3 seeds per fruit. The seeds are similar in appearance to their fruits, but a little shorter and more slender. The root system consists of a whitish crown with fibrous roots. [图片]Cultivation: The preference is full sun, wet conditions, and a barren calcareous soil containing an abundance of sand or gravel. This plant is intolerant of competition from other ground vegetation. It is quite cold-hardy. [图片]Range & Habitat: The native Slender Arrowgrass (Triglochin palustris) is rare in Illinois, where it is state-listed as 'endangered.' It is found in the NE section of the state and 2 counties toward the center of the state (see Distribution Map). Illinois lies along the southern range-limit of this species. In the United States, Slender Arrowgrass occurs in the New England region, Great Lakes area, Northern Plains, and scattered areas of the western states. It also occurs in Canada, Eurasia, and New Zealand. In Illinois, habitats consist primarily of fens, calcareous gravelly seeps, marl flats, and calcareous sandy pannes near Lake Michigan. This very conservative plant is restricted to high quality natural areas within the state. [图片]Faunal Associations: Floral-faunal relationships of this plant in Illinois are not known. Further to the north in Canada and Alaska, the foliage and especially the whitish crowns are a preferred source of food for the adults and goslings of several species of geese, including Branta canadensis (Canada Goose), Branta bernicula nigricans (Black Brant Goose), and Chen caerulescens (Lesser Snow Goose). The foliage and crowns of Slender Arrowgrass (Triglochin palustris) are reportedly high in protein and low in fiber (Mulder et al., 1996; Prevett et al., 1985). [图片]The foliage also contains hydrocyanic compounds that can be toxic to sheep and cattle if it is consumed in sufficient quantity. There is some evidence in Europe that the seeds of this plant can cling to the fur of deer and cattle. Thus, these animals can spread the seeds to new areas (Mouissie et al., 2005). Photographic Location: A gravelly seep in McHenry County, Illinois. [图片]Comments: This plant is not very showy and it is easily overlooked. The only other species of this genus that occurs in Illinois, Sea Arrowgrass (Triglochin maritima), is also very rare within the state and it occurs in similar areas. Sea Arrowgrass is a little larger and stouter than Slender Arrowgrass (Triglochin palustris) overall. Its fruits (schizocarps) have a wider ovoid shape and they divide into 6 sections (6 seeds per fruit), rather than 3 sections. Unlike Slender Arrowgrass, the central axis of its fruit is not winged. The wind-pollinated flowers of these plants are rather odd-looking because their feathery stigmas resemble tufts of hair that are typically found on seeds. An alternative spelling of the scientific name for Slender Arrowgrass is Triglochin palustre, and another common name of this plant is Marsh Arrowgrass.

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Miss Chen

2018年06月15日

Description: This herbaceous perennial wildflower is 3-7' tall and largely unbranched, except for the short flowering stalks along the upper one-fourth of its length. The central stem is terete, light green, and either glabrous or canescent. The alternate leaves are 3-8" long and and 2-4" across; they are ovate to broadly ovate and crenate-dentate along their margins. Some leaves may have a pair of lobes that are shallow and broad. The upper leaf surface is yellowish green to medium green and glabrous (or nearly so), while the lower leaf surface is pale green and canescent. The slender petioles are 2-5" long and either light green or reddish green. At the base of each petiole, there is a pair of small linear stipules. The upper flowering stalks are 1½–3" long and canescent; each stalk has a single leaf and a single flower. Individual flowers are 4-6" across and a similar length, consisting of 5 white or pink petals, 5 light or yellowish green sepals, a reproductive columnar structure with numerous stamens along its length and 5 styles with knobby stigmata at its apex. The persistent sepals are ovate and canescent (or tomentose); they are united at the base. Each flower usually has a reddish purple throat at the base of its petals, although sometimes this is absent. Directly underneath the sepals, there are about 12 linear bracts that curve upward; they are 1" in length. The blooming period occurs from mid-summer to early fall and lasts about 1 month. Individual flowers are short-lived; usually only 0-2 flowers are in bloom at the same time on a single plant. The flowers are replaced by seed capsules that are about 1–1¼" long and a little less across; they are globoid-ovoid, short-beaked, and glabrous. Each seed capsule contains a ring of seeds; individual seeds are reniform, flattened, and hairless. This wildflower spreads by reseeding itself. Cultivation: The preference is full to partial sun, wet to consistently moist conditions, and soil containing loam, silt, or some sand with organic material. Close-up of Flower Range & Habitat: The native Swamp Rose Mallow is found in widely scattered localities along the eastern half of Illinois, where it is uncommon. Illinois lies near the NW range-limit for this species in North America. Swamp Rose Mallow is also found in east Asia, where some additional color forms exist. Habitats include marshes, open swamps, and low soggy areas along rivers and ponds. Along the Atlantic coast of the U.S., this wildflower is also found in brackish marshes. Because of its attractive flowers, Swamp Rose Mallow is cultivated occasionally in gardens; some cultivars display evidence of hybridization with other Hibiscus spp. (Rose Mallows). [图片]Faunal Associations: The flowers are cross-pollinated by bumblebees and other long-tongued bees, including Melitoma taurea and Ptilothrix bombiformis (Rose Mallow bee). The Rose Mallow bee is a specialist pollinator (oligolege) of native Hibiscus spp. (Rose Mallows); it sucks nectar and collects pollen from the flowers, while other long-tongued bees suck nectar primarily. The Ruby-Throated Hummingbird is another nectar-seeking visitor of the flowers. Some insects feed on various parts of Rose Mallows. The introduced pest, Popillia japonica (Japanese Beetle), gnaws on the flowers and young leaves, while the aphids Aphis gossypii and Macchiatiella rhamni suck plant juices. The caterpillars of Pyrgus communis (Common Checkered Skipper) and the butterfly Vanessa cardui (Painted Lady) sometimes feed on the leaves, while the caterpillars of the butterfly Strymon melinus (Gray Hairstreak) feed on the developing seeds. The caterpillars of several moths also feed on Rose Mallows, including Acontia delecta (Delightful Bird-Dropping Moth), Anomis erosa (Yellow Scallop Moth), Automeris io (Io Moth), and Eudryas unio (Pearly Wood Nymph). Photographic Location: A prairie swale at Meadowbrook Park in Urbana, Illinois. Comments: Swamp Rose Mallow has exotic oversized flowers that are very striking, particularly when they occur in a colony of plants. Other native Hibiscus spp. (Rose Mallows) in Illinois are similar to Swamp Rose Mallow in appearance and they are found in similar habitats. These species include Hibiscus lasiocarpos (Hairy Rose Mallow) and Hibiscus laevis (Halberd-Leaved Rose Mallow). Hairy Rose Mallow has felty leaves that are conspicuously hairy on both their upper and lower surfaces; Swamp Rose Mallow has leaves that are hairless (or nearly so) on their upper surfaces. Hairy Rose Mallow also has hairy ovaries/capsules, while the ovaries/capsules of Swamp Rose Mallow are glabrous. Sometimes Hairy Rose Mallow is regarded as a subspecies of Swamp Rose Mallow, or Hibiscus moscheutos lasiocarpos. The remaining similar species, Halberd-Leaved Rose Mallow, has leaves with divergent basal lobes (shaped like a halberd) or palmate lobes (maple-leaf shaped), leaf surfaces that are hairless on both the lower and upper sides, and seeds that are quite hairy. In contrast, Swamp Rose Mallow lacks such strongly lobed leaves, the lower surfaces of its leaves are canescent (or tomentose), and its seeds are hairless. In the past, the pink-flowered form of Swamp Rose Mallow that lacks a reddish purple throat was classified as a distinct species, Hibiscus palustris. However, it is now considered one of several color forms of Swamp Rose Mallow.

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Miss Chen

2018年06月15日

Description: This perennial plant is 3-6' tall, branching sparingly. The stems are terete and glabrous. The alternate leaves are up to 6" long and 4" across (excluding the petioles); they are usually divided into 3-5 pointed lobes and their margins are serrate-crenate. Leaves with 3 lobes resemble a medieval halberd because the middle lobe is much longer than the 2 lateral lobes. Leaves with 5 lobes have the shape of a maple leaf. Some of the leaves may be unlobed; they are lanceolate to ovate in shape. The leaves are glabrous and their venation is partially palmate. The petioles are long and slender. The upper stems terminate in either a solitary or small cluster of flowers. Each flower is up to 5" across when fully open, consisting of 5 rounded petals, a columnar reproductive structure, and a green calyx with 5 oval lobes. The petals are pink to nearly white. The reproductive column consists of whorled stamens and a divided style at its tip. The throat of the flower is reddish purple. Around the base of the calyx, there are several linear bracts. The blooming period occurs from mid- to late summer, lasting about 1 month. Each flower lasts only a single day. The rather large seeds are finely hairy and irregularly shaped – they tend to be flat-sided and reniform, but this is not always the case. Their fine hairs are white or brown. The seeds are light for their size, and probably distributed by movement of water. The root system consists of a taproot. This plant spreads by reseeding itself. [图片]Cultivation: The preference is full or partial sun, fertile soil, and wet conditions. Flowers require exposure to sunlight to open up properly. This wetland species doesn't like to dry out. Range & Habitat: The native Halberd-Leaved Rose Mallow has been observed in most areas of Illinois, except for extreme northern Illinois and some south central areas of the state (see Distribution Map). Habitats include marshes, swamps, low areas along rivers and ponds, and soggy islands in the middle of rivers or ponds. It is not often found in highly disturbed areas, and doesn't compete well against the invasive Salix interior (Sandbar Willow). [图片]Faunal Associations: The nectar and pollen of the flowers attract bumblebees and an oligolectic bee, Ptilothrix bombiformis. Another common floral visitor, Melitoma taurea, is oligolectic on Ipomoea spp. (Morning Glory), but it is attracted to the large funnelform flowers of other plants. Some insects feed destructively on Hibiscus spp. (Rose Mallow). Caterpillars of the butterfly, Strymon melinus (Gray Hairstreak), feed on the flower buds and developing seeds, while caterpillars of the butterfly, Vanessa cardui (Painted Lady), feed on the foliage, as do caterpillars of Pyrgus communis (Checkered Skipper). Larvae of such moths as Eudryas unio (Pearly Wood Nymph), Anomis erosa (Yellow Scallop Moth), Automeris io (Io Moth), and Acontia delecta (Delightful Bird-Dropping Moth) also feed on these plants; the latter moth is found south of Illinois, however. [图片]Other insect feeders include the flea beetle Chaetocnema quadricollis, larvae of the sawfly Atomacera decepta, the jewel beetle Paragrilus tenuis, adults of Popillia japonica (Japanese Beetle), and some aphid species. Deer and livestock will eat the non-toxic foliage of native Hibiscus spp. readily. However, the introduced shrub, Hibiscus syriacus (Rose-of-Sharon), which is often planted in yards, is apparently more resistant to browsing by deer than the native Hibiscus spp. Photographic Location: Along a large drainage ditch at the Windsor Road Prairie in Champaign, Illinois, where this species was introduced. [图片]Comments: Halberd-Leaved Rose Mallow has large beautiful flowers that can be seen from a distance. Other native Hibiscus spp. in Illinois include Hibiscus moscheutos (Swamp Rose Mallow) and Hibiscus lasiocarpus (Hairy Rose Mallow). Halberd-Leaved Rose Mallow can be distinguished by its lobed leaves, as the latter two species have unlobed leaves that are oval-ovate in shape. While Halberd-Leaved Rose Mallow has hairless leaves and hairy seeds, Swamp Rose Mallow and Hairy Rose Mallow have hairy leaf undersides and hairless seeds! All of these species have similar flowers and they prefer similar wetland habitats, although Hairy Rose Mallow has a more southern distribution within the state. A scientific synonym of the Halberd-Leaved Rose Mallow is Hibiscus militaris.

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