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Violet bush-clover produces racemes or sparsely branched panicles of 3-8 flowers from the tips of stems or axils of middle or upper leaves; the inflorescences are borne on long peduncles that extend above/beyond the leaves. Individual flowers are 6-10 mm long and pea-like; they include a light green calyx with five teeth that is half the length of the flower; five whitish purple to purple petals (one upright banner with a basal patch of rosy purple; two lower, outer wings shorter than the keel; and two lower, inner petals that make up the keel); 10 stamens; and a pistil with a single style. Both the stamens and style are usually hidden within the keel. Fertilized flowers produce small green, single-seeded seedpods that lack sticky hairs (unlike the much-larger tick-trefoils); at maturity, the seedpods are 4-7 mm long and dark brown.

Lespedeza

Lespedeza frutescens

violet bush-clover [Blooms: Aug-Sep]

Rough blazing star's floral spike grows directly from the stem 6-18" long, with composite flowerheads along its length. Very early buds may appear as white, miniature cabbage-like structures, with purple highlights. Flowerheads open from the apex and proceed in a wave towards the base of the inflorescence. Flowerheads are about 1" across and usually stalkless. They are composed entirely of 25-40 disc florets (no ray florets), each with a tubular pinkish-purple corolla with five sharply-pointed apical lobes; a very long divided style emerges from the center of the corolla and the five brown anthers are inserted side by side around the base of the style. The exterior of the flowerhead is covered with 4-5 overlapping series of green or purple-tinged broadly rounded bracts whose edges are rolled in and rough with series of distinct, tiny teeth. Rocky Mountain blazing star's bracts look very similar to rough blazing star's, but the flowerheads of rough blazing star are essentially sessile (flower stalk no more than 1/4" long) while the flowerheads of Rocky Mountain blazing star have significant stalks, most commonly 1/2-1" long (as long as the flowerhead). The Jackson Park blazing stars bloom in the order cylindrical, prairie, rough, marsh, and Rocky Mountain; in relative abundance, rough is the most common, followed by cylindrical, prairie, marsh, and Rocky Mountain. Quick key to the Jackson Park blazing stars: bracts covering base of the flowerhead are (1) sharply pointed (-> cylindrical), (2) recurved away from flower, flaring (-> prairie), (3) tip round, closely appressed (-> marsh), (4) margins with tiny teeth, rolled under (-> rough if flower stalk is very short, Rocky Mountain if flower stalk about same length as flowerhead).

Liatris

Liatris aspera

rough blazing-star [Blooms: Aug-Sept]

Cylindrical blazing star is a more open plant than the other Jackson Park blazing stars, with the flowerheads relatively widely spaced along the 2-4" long racemes that are perched atop a 1-1.5' tall, unbranched stem. The showy flowerheads are pink or purplish-pink, about 1/2-3/4" in diameter, sessile or held on up to 3/4" stalks, with 15-25 disk flowers and no ray flowers; the base of the flowerheads is covered with 5-7 layers of scale-like, overlapping bracts with a sharp tip that together form a slim cylinder ~3/4" long and 1/3" diameter. The disk florets are tubular with five recurved triangular flaps at their apex; a pinkish white style, surrounded at its base by the five closely-packed yellowish-brown anthers and divided distally into two long filaments. Cylindrical blazing star appears to prefer dryer, well drained soils. The Jackson Park blazing stars bloom in the order cylindrical, prairie, rough, marsh, and Rocky Mountain; in relative abundance, rough is the most common, followed by cylindrical, prairie, marsh, and Rocky Mountain blazing stars. Quick key to the Jackson Park blazing stars: bracts covering base of the flowerhead are (1) sharply pointed (-> cylindrical), (2) recurved away from flower, flaring (-> prairie), (3) tip round, closely appressed (-> marsh), (4) margins with tiny teeth, rolled under (-> rough if flower stalk is very short, Rocky Mountain if flower stalk about same length as flowerhead).

Liatris

Liatris cylindracea

cylindrical blazing-star [Blooms: Jul-Aug]

Rocky Mountain blazing star (aka, northern plains blazing star) is the least common of the blazing stars in Jackson Park. Flowerheads lack ray florets but have 30-100 disc florets. Rocky Mountain blazing star flowerheads most closely resemble those of rough blazing star in that the bracts covering the base of the flowers in both have their edges rolled under with toothed edges, but the bracts in Rocky Mountain blazing star tend to flatten with age. The best way to distinguish the two species is by the length of the flowerhead's stalk —  the flowerheads of rough blazing star are essentially stalkless (stalks 1/4" long max) while those of Rocky Mountain blazing star are typically 1/2-1" long or longer, often the same size or longer than the flowerhead itself. Illinois is on the eastern edge of Rocky Mountain blazing star's range, so it's a fairly rare sight here. Quick key to the Jackson Park blazing stars: bracts covering base of the flowerhead are (1) sharply pointed (-> cylindrical), (2) recurved away from flower, flaring (-> prairie), (3) tip round, closely appressed (-> marsh), (4) margins with tiny teeth, rolled under (-> rough if flower stalk is very short, Rocky Mountain if flower stalk about same length as flowerhead).

Liatris

Liatris ligulistylis

Rocky Mountain blazing-star [Blooms: Aug-Sep]

Savanna blazing-star's inflorescence is a long (up to 24"), narrow raceme of 10-40 flowerheads blooming in order from the tip of the inflorescence downwards. Each flowerhead has a 1/2-3.5" long, ascending stalk (peduncle); flowerheads are usually solitary on the peduncle. A sessile, leafy bract resembling the leaves occurs at the base of each peduncle. The central stalk of the inflorescences and the peduncle are fuzzy with short, white hairs. Each flowerhead is 1-2" across; they have 20-80 disk florets and no ray florets. The disk florets are tubular with five narrow, spreading lobes. The styles are bifurcated and extend well beyond the corolla of the disk florets, giving the flowerheads a shaggy aspect. There are five stamens hidden within the throat of the disk floret; the black anthers are visible, appressed to the body of the style. Surrounding the base of the flowerhead are scale-like bracts (phyllaries) in 4-6 overlapping series; they are slightly spreading and angled upwards but are neither appressed nor recurved. Individual phyllaries are oval or egg-shaped with short hairs protruding from their margins; they are often dark purple when the flowerhead is blooming. The fruit is a cylindrical, black seed with a tuft of white hairs about twice as long as the seed on one end. Preferred habitats are sandy savannas. Skippers and monarch butterflies seem particularly fond of savanna blazing-star. Savanna blazing-star might be confused with the much more common rough blazing star (Liatris aspera), but the latter always has appressed phyllaries with toothed, incurved edges, in contrast to savanna blazing-star's spreading, flat phyllaries and a much shorter stalk beneath the flowerhead than is present in savanna blazing-star. NatureServe Explorer (https://explorer.natureserve.org) rejects the name "Liatris scariosa" in favor of "Liatris novae-angliae" but ITIS (www.itis.gov)rejects the latter, as does the USDA Plants website(https://plants.usda.gov/). Here we will follow the latter two sources.

Liatris

Liatris scariosa

savanna blazing-star [Blooms: Aug]

Wild lupine is Illinois' only native lupine. The plant is small (1-2.5' tall) with light- to reddish-green stems with a grey cast from profuse short hairs (as are the leaves and leaf petioles). The flowers are blue-violet, typical pea-like flowers ~3/4" long, similar in structure to wild indigo flowers (five petals — a banner, two wings, and two keels). The fruits are 1-2" long, hairy pea-like seed pods, black when mature. The palmately-compound leaves with such a profusion of leaflets are distinctive. Wild lupine is the only known host plant for the caterpillars of the Karner Blue Butterfly (Lycaeides melissa samuelis), a federally listed endangered species.

Lupinus

Lupinus perennis

wild lupine [Blooms: May-Jun]

Winged loosestrife is a native species that has a central stem up to 3' tall, much more modest that its notorious cousin, purple loosestrife. The stem is four-sided, narrowly winged, and largely hairless; wings run along the stem but are interrupted at the leaf nodes. The inflorescence is a spike up to 1.5' long; the flowers develop singly or in pairs from the axils of bracts on the inflorescence. Each flower is pale lavender or purple and smaller than the flowers of purple loosestrife (1/4-1/2") but otherwise superficially similar — pale purple or lavender, six wrinkled petals with a medial purple stripe, six stamens. The light green, narrow calyx is about as long as the petals, has six (not five) lance-shaped teeth, and bold longitudinal stripes. The style may or may not protrude from the corolla — the flowers are distylous so the styles may either lie just inside the flower throat or protrude well outside; the style has a fuzzy, green, globular stigma. The fruit is a capsule that develops in the remnants of the calyx. Winged loosestrife prefers wet soils and is a less showy plant than purple loosestrife, but it is a native plant that plays nicely with its neighbors.

Lythrum

Lythrum alatum

winged loosestrife [Blooms: Jun-Aug]

Common mallow flower stalks arise from the leaf axils. They are 1/2-1" long, attached to one to three, 1/4-1/2" wide flowers. Individual flowers have a green calyx with five pointed, triangular lobes half the length of the petals; white or pale violet squared-off petals with a shallow notch and pale violet lines; the 12-15 stamens make a bumpy, white globe around the 12-15 fused pink styles in the middle of the flower, with the inner surface of the style tips as the stigmas. The fruit is a round, flattened ovoid with radiating lines (the edges of the carpels) around a dimpled center, nestled in the remains of the calyx. Some people claim that the fruit resembles a wheel of cheese (thus one of the common names); it reminds me more of a miniature gourd. All parts of this plant are edible.

Malva

Malva neglecta

common mallow [Blooms: May-Oct]

French grass flowers are 1/4" long, pea-like, with a short, green, tubular calyx with five teeth, and five blue, purple, or white petals — a single upright banner, two forward-projecting wings, and two closely-appressed petals that make up the keel (largely hidden by the wings). Ten stamens and the style are nestled inside the keel. Seedpods are about 1/2" long with a stout, pointed "beak."

Orbexilum

Orbexilum onobrychis

French-grass [Blooms: Jun-Jul]

Giant reed is a grass that grows 4-16' tall (the tallest native grass in Illinois), often in dense, clonal stands. The culm (stem) is greyish-blue or light green; the base of the culm may be 15 mm (about 5/8") across. The culm ends in a panicle up to 1.5' long and half as wide of spikelets. When the florets are blooming, the panicle of spikelets has a reddish, silky appearance. Each spikelet is 12-17 mm long containing 3-7 florets. At the base of the spikelet is a pair of scale-like glumes (bracts) at about a 30° angle to each other; the base of the upper glume is nested inside the base of the lower glume, and both have a long, tapered, pointed tip. The glumes are typically 4-6 mm (1/4") long. Above the glumes, along the central axis of the spikelet (rachilla) are a series of progressively-shorter bracts (lemma and palea — more delicate versions of glumes — surrounding each floret) and tufts of silky hairs 1 cm long attached to the rachilla and obscuring the florets. The most basal floret is either sterile or is staminate; the remaining florets containing both male and female reproductive organs (= "perfect"). Staminate and perfect florets contain 1-3 stamens with purple anthers; perfect florets also have two long, feathery styles. The florets are wind-pollinated. After fertilization, individual seed grains replace the florets.

Phragmites

Phragmites australis

giant reed [Blooms: ?early-midsummer]

Upright prairie coneflower (aka, "Mexican hat") is a 1-3' tall plant native to North America but an exotic in Illinois; it looks like English plantain (Plantago lanceolata) dressed up for a party. The stems are green and longitudinally ridged; they bear alternate, pinnatifid leaves with 5-11 elongate, narrow lobes. The upper stems produce flower stalks (peduncles) 2-12" long, minutely grooved, and lacking leaves; the peduncles are very "wire-like." The flowerheads are 1.5-3" long cylinders composed of numerous brown or purplish disk florets that bloom from the bottom of the cylinder to the top; at the base of the cylinder are 4-12 ray florets with drooping, 1/2-1.5" long, oblong petals with notched tips that are yellow, maroon, or yellow with basal maroon patches (the "party skirt"). This plant is unmistakable when in bloom. The imaged flower was photographed in Bobolink Meadow in July, 2010; I have not seen a specimen since.

Ratibida

Ratibida columnifera

upright prairie coneflower [Blooms: Jul]

Purple-flowered raspberry's flowers are large (up to 2-3") with five sepals densely covered with reddish glandular hairs, bluntly triangular, about half the length of the petals with long, thread-like tips; five magenta, rounded, laterally overlapping petals surrounding a compact ring of 20-100 thread-like stamens with yellow anthers; and a central mound of several hundred pale yellow, club-shaped styles. The fruit is a typical drupe, 3/4" in diameter, reddish-pink when mature, more flattened than a commercial raspberry. It can be hard to find on the plant — it is very popular with birds. Between the maple-like leaves and the showy, magenta flowers, purple-flowered raspberry is impossible to confuse with any other Rubus spp. in Illinois. Purple-flowered raspberry prefers partial shade (like woodland edges); it is critically endangered in Illinois.

Rubus

Rubus odoratus

purple-flowered raspberry [Blooms: Apr/May-Aug]

Weeping willow is an exotic, probably originally bred in Asia or Europe. It is not very cold tolerant, so most "weeping willows" growing north of Kentucky or Virginia are actually hybrids. The aesthetically delightful "weeping" forms with yellow branches (the "golden" variety) are most likely a hybrid of Salix babylonica and Salix alba. There are separate male and female inflorescences in the form of catkins; each tree only produces one sex of catkins. The male catkins are 1-2" long and have no petals — only a series of stamens with white filaments and large (usually yellow) anthers. The female catkins are smaller (1" or less) and less showy with a series of green floral bracts that look like a series of awnings over 2-4 styles with flat stigmas; after fertilization they produce a green to brown capsule that releases cottony seeds.

Salix

Salix babylonica

weeping willow [Blooms: Apr]

Horsenettle's upper stems end in small clusters of 3/4" wide white or light violet flowers with wavy petal margins and hairy pedicels; clusters may also arise from leaf axils. Each flower has a green, hairy calyx with five lobes that taper gradually to sharp tips (typically slightly reflexed); five triangular petals that are fused at their bases; and five yellow, banana-shaped anthers 6-9 mm long surrounding a long, slim, light green style with a darker green, globular terminal stigma. After fertilization, the ovary expands into mature berries about 1/2" in diameter, initially green-striped, that look like yellow cherry tomatoes when mature; they are half enclosed in a papery derivative of the calyx.

Solanum

Solanum carolinense

horsenettle [Blooms: Jun-Aug]

Bittersweet nightshade flowers occur in small (6-12 flowers) clusters arising from the stems and leaf axils. Each flower is about 3/8" across consisting of a small green, purple, or brown calyx with five shallow, triangular lobes; five petals, purple with paired yellow or green spots at their bases, that flare or are reflected backwards over the base of the flower; five bright yellow anthers 4.5-6 mm long that are appressed to form a tight cylinder; and a single green, slender style closely surrounded by the anthers and protruding beyond them. The fruit is a 3/8-1/2" long, oval, tomato-like berry, initially green; mature berries are bright red. The foliage and fruit contain the alkaloid solanum and are toxic; fatalities are rare but have occurred. Horse nettle (S. carolinense) is similar to bittersweet nightshade but has numerous sharp bristles and spines on the stems and leaves that are lacking in bittersweet nightshade. Black nightshade (S. ptycanthum) is also similar but has black (rather than red) mature fruits and white (not purple) petals on the flowers.

Solanum

Solanum dulcamara

bittersweet nightshade [Blooms: May-Aug]

Smooth blue aster's central stem produces a one-half to one foot long (and half as wide) panicle of flowerheads with stiff, ascending branches covered with small, leafy bracts. Smaller panicles may arise from some lateral upper stems and the axils of the upper leaves. Individual flowerheads are 0.5-1" wide, consisting of 15-30 light lavender or light blue-violet ray florets and 19-33 disk florets that are initially a whitish yellow but change to purplish red over time. The phyllaries that cover the back of the flowerhead are arranged in 4-6 overlapping series and have a diamond-shaped, green tip, often with a spot of red at the very tip. The fruit is a brown, dry seed, flattened, narrowly cone-shaped with 4-5 longitudinal ribs, 2-4 mm long with a tuft of brown hair. The most useful character to distinguish smooth blue aster from other asters is the lack of hairs on its stems and leaves; the uniformly clasping leaves (no petioles) is another useful character. For example, the superficially similar skyblue aster (Symphyotrichum oolentangiense) has lower and middle leaves with distinct petioles and none of its leaves actually clasp the stem.

Symphyotrichum

Symphyotrichum laeve

smooth blue aster [Blooms: Aug – Sep]

Clusters of flowerheads occur at the tips of the upper stems of New England asters. Individual flowerheads are large (1.5" across) with 50-75 (!) purple, lavender, or pink ray florets; the 50-110 disk florets are yellow or gold, turning reddish purple with age. A healthy New England aster with two or three dozen flowerheads is an impressive sight indeed. Phyllaries surround the back of the flowerhead in 3-5 layers. They are green or purple-tinged, very narrow but robust, widely spreading or reflexed, with the outermost layer of phyllaries covered with short glandular hairs. The fruit is a longitudinally ribbed, quite hairy, dry seed with a tuft of long, light brown hairs. The large, showy flowerheads with very large numbers of ray florets (petals) can't be confused with any other aster in Jackson Park.

Symphyotrichum

Symphyotrichum novae-angliae

New England aster [Blooms: Aug – Nov]

The panicles of Short's aster's flowerheads are up to 18" long and 8" across; the panicles arise from the tips of the central stem and the upper lateral branches. The flowering branches are long, widely spreading or arching, and covered with small, leaf-like bracts and stiff hairs. Individual flowerheads are 3/4-1" across. Flowerheads consist of 10-20 lavender or pale blue-violet (rarely white) ray florets and 15-23 disk florets, initially yellow but becoming reddish purple over time. The phyllaries that surround the base of the flowerheads are covered with stiff, white appressed hairs, are whitish or light green with a diagnostic dark green, diamond-shaped tip, and sometimes also with a dark green medial vein. The fruits are 2-3 mm long, oblong-shaped, with a tuft of light brown hairs at one end. The indented bases of the lower and middle leaves, the slender, wingless petiole, the hairless leaves, and the phyllaries with dark green apical diamonds together are good indicators of Short's aster. Short's aster is the commonest aster in bloom in Jackson Park in early autumn; later in the autumn it is overtaken in numbers (or at least visual impact) by New England asters.

Symphyotrichum

Symphyotrichum shortii

Short's aster [Blooms: Aug – Nov]