Showing 163–180 of 372 results

Filtered (372)
Field peppergrass tems produce racemes of flowers near their apex; flowers near the top of the raceme are the youngest with older flowers (and later seed pods) further down the inflorescence. The flowers have a calyx of green or purple-green, lance-like sepals, four white, spoon-shaped petals, six stamens, and a single style. The fruits are flattened pods oval in outline with the remnants of the style protruding from a notch in the end (rather like field pennycress, Thlaspi arvense); each seedpod contains two seeds. This is an easy plant to overlook if only because it look like the weed that it is.

Lepidium

Lepidium campestre

field peppergrass [Blooms: May-?]

Peppergrass (aka, Virginia pepperweed) is a weedy, 1.5' tall, rather bushy plant. The flower spikes (racemes) are 2-4" long with tiny (<1/8") white apical flowers forming a larger inflorescence. The flowers have four oblong green or tan sepals with a white edge, half the length of the petals, alternating with four white, triangular petals. There are two stamens with yellow anthers and a stubby (0.2 mm tall) style on a green ovary. Below the flowers, the flower spike is covered with 1/8" wide seedpods on (relatively) long stalks, reminiscent of a bottlebrush; the seedpods are oval with an apical notch (much like half-sized versions of field pennycress (Thlaspi arvense) seedpods) containing two seeds. This species is native to the U.S. The stubby cylindrical inflorescences are and the triangular petals alternating with shorter sepals are diagnostic and distinguish pepper grass from field peppergrass (Lepidium campestre).

Lepidium

Lepidium virginicum

peppergrass [Blooms: Oct-Nov]

Round-headed bush-clover present stout, tall (2-5') green columns in the middle of open habitats. The stem is unbranched below the midpoint (except at the inflorescences), round in section, grooved, and densely covered in white hairs. At the apex of the main stem and on some of the side stems are slightly elongated balls of flowers 3-5" long and half as wide with numerous clover-like white flowers nearly hidden among leafy bracts; brown flowerheads and stalks may persist through winter. Each clover-like flower is about 1/4" wide and 1/2" long with five petals, one large vertical upper petal ("standard") and two perpendicular side petals ("wings") are visible; the other two petals (forming the keel) are hidden from view by the wings. There are ten stamens, all but one with their filaments fused together, and a single style with a small stigma. The petals are white with a patch of reddish-purple near the junction of the three visible petals. The fruit is a fuzzy pod less than 1/4" long containing a single seed. Round-headed bush-clover is a perennial with a tap root that may go down two meters into the soil.

Lespedeza

Lespedeza capitata

round-headed bush-clover [Blooms: Aug-Sep]

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]

Ox-eye daisy is an aggressive plant that was introduced to the U.S. in the 19th century and is now thoroughly naturalized. Flowerheads occur singly at the apex of the stem on a long flower stalk. The flowerheads are about 1.5-2" across with 15-35 brilliant white, oblong ray florets and 120-200 yellow disc florets in a central, flattened disc about 3/4" across. The ray florets are fertile (they bear pistils with a split stigma) while the disc florets have both pistils and stamens. The disc florets are tubular with five tiny lobes at the apex, five stamens, and a single style with a bifurcated tip. The underside of the flower has numerous bracts in 2-4 layers; the bracts are green with purple to brown edges that outline each bract.

Leucanthemum

Leucanthemum vulgare

ox-eye daisy [Blooms: May-Jul]

Lyme grass flower spikes are 5-14" long, initially blue-green or silvery but turning beige when mature. There are typically one pair of spikelets per node on the spike. The spikelets are 1/2-1" long, containing 2-5 (typically 3) florets; each floret contains two bottlebrush-like styles and 1-3 stamens, each typically with a single yellow anther. Like all grasses, Lyme grass is wind pollinated. Lyme grass is very similar to the native American dune grass (Leymus mollis) but the latter is greener and is finely hairy under the spike. Lyme grass has become established in sandy habitats around the Great Lakes and (curiously) along the coast of Greenland.

Leymus

Leymus arenarius

Lyme grass [Blooms: May-Jun]

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]

Prairie blazing star's stem ends in a spike of composite, purple flowerheads 1/4-1/2" across; pinkish-red bracts cover the underside of the flowerheads, tapering to a fine tip that dramatically curls away from the flowerhead (like the scales on a dry pine cone). (No other blazing stars have such recurved bracts.) Each flowerhead has 5-10 disc florets that are tubular, 7-10 mm long, with five lobes at the apex forming a prominent star shape. A hairy, divided style protrudes well beyond the apex of the corolla; the base of the style is surrounded by the 3 mm long, reddish-brown anthers of the five stamens. Prairie blazing stars prefer well-watered areas. 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 pycnostachya

prairie blazing-star [Blooms: Jul-Aug]

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]

Marsh blazing star flower spikes are 4-18" long extensions of the main stem, crowded with pinkish-purple flowerheads facing in all directions. Individual flowerheads are about 8 mm across; ray florets are absent and the 4-10 disc florets dominate. The corolla of a disc floret is tubular with five lance-shaped apical lobes; the divided style extends well outside the tubular corolla, surrounded at its base by five tightly packed stamens. The base of the flowerhead is covered with overlapping, flattened, elongate-oval bracts with rounded tips. Marsh blazing star is similar to prairie blazing star in appearance, but the bracts of prairie blazing star are highly recurved (like the scales on a dry pine cone). 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 spicata

marsh blazing-star [Blooms: Aug]

Butter-and-eggs (aka, toadflax) is an exotic, native to Europe and Asia. The stem is 1-2' tall, usually unbranched, terminating in an elongate (3-6" long) flower spike. The 1" long, yellow and orange, snapdragon-like flowers with a long nectar spur are distinctive. The vertically-oriented, tubular corolla has an upper and lower lip, each divided into two lobes that curve away from the axis of the flower. There are four fertile stamens of two distinct lengths hidden inside the corolla and a single style. The flowers are mostly pollinated by bumblebees, which are strong enough to push their way into the flower and have a long enough tongue to access the nectar.

Linaria

Linaria vulgaris

butter-and-eggs [Blooms: Jul-Oct]

Spicebush is a highly branched, woody shrub that reaches heights of 5-15'. It blooms very early in the spring — March and April in Jackson Park, before most plants have leafed out — so it is one of the few spots of color in a grey landscape. When spicebush blooms, leaves are not yet present; the small clusters of yellow flowers have the stage all to themselves. Some specimens have only a single sex of flower (pistillate or staminate); less commonly, spicebush plants may bear "perfect" flowers with both functional male (stamens) and female (pistils) organs. Individual flowers are about 1/4" across, pastel-yellow, with six yellow, petal-like tepals. Male flowers have nine stamens in three groups of three, each group associated with a two-lipped, yellow nectary; The anthers are bright yellow. Female flowers have an ovary with a single pistil and 6-18 non-functional pseudo-stamens; the stigma is large, bright white, and rough-surfaced. The flowers are said to have "an unusually sweet fragrance." The fruit is a fleshy drupe with a single stone; it turns bright red in the late summer/early fall.

Lindera

Lindera benzoin

spicebush [Blooms: Mar-Apr]

Tulip trees are the tallest native hardwood — one living specimen is 190' tall, the tallest tree east of the Mississippi. (Most tulip trees are in the 80-100' range). Illinois is on the western edge of tulip trees' range, but it is the state tree of Indiana (and Tennessee). Tulip trees have a single trunk and (usually) a pyramidal crown; the bark is gray with whitish furrows. Flowers arise on short stalks in leaf axils. Each flower is bell-shaped, erect, 2-3" across, and ~2.5" tall; there are 9 tepals — 3 pale green sepal-like tepals reflected downward and 6 fleshy petal-like tepals, yellowish-green to green in their upper half with an broad orange stripe below; the very base of the petal is pale yellow-green. In the middle of the flower is a tall (2.5") conical cluster of 60-100 pistils (the receptacle); surrounding the receptacle are 20-50 white stamens with yellow anthers. The fruit is a 1.5" long winged seed (samara) reminiscent of an ash seed; the ovate seed lies at one end of a long, thin wing with a central ridge. The leaves alone are sufficient for a confident identification; in flower or in the fall when the receptacle has produced a crown-like circlet of woody, persistant basal samaras, tulip trees are unmistakable.

Liriodendron

Liriodendron tulipifera

tulip tree [Blooms: June]

Hairy puccoon flowers are 3/4" across with a VERY hairy, green calyx with five sharply-triangular teeth , a yellow to yellow-orange tubular corolla with five widely-spreading rounded lobes, five stamens hidden inside the corolla beneath the throat, and a single style with a two-lobed, disc-like stigma. The flowers of hairy puccoon are heterostylous; i.e., either they have long stamens (~14 mm) and a short style (2-5 mm) or short stamens (~3 mm) with a long style (5-12 mm), but neither the anthers nor the stigma extend beyond the throat of the corolla (although they may get close). Hairy puccoon is very similar to hoary puccoon (L. canescens) but with stems that are less hairy and the hairs are "disorganized." The calyx at the base of the floral tube are very hairy in both species, but the teeth of the calyx in L. caroliniense have a distinct keel running down their midline. (I.e., subspecies L. caroliniense croceum.) Flowers of hairy puccoon are larger — up to 1" vs. 1/2" in hoary puccoon. The fruit is an egg-shaped nutlet, white when mature.

Lithospermum

Lithospermum caroliniense

hairy puccoon [Blooms: May-Jun]

Cardinal flower is an unmistakable bright red (rarely white), orchid-like flower that prefers wet habitats. A mature plant is 2-3.5' tall; the stem is light green, round in section, and hairy. The stem terminates in a 1/2-1.5' long raceme of bright red flowers. At the base of the flower is a green calyx with five very long, narrow, usually-spreading lobes. The corolla is 1-1.5" long and 3/4-1" across; it is strikingly vertically-oriented. Rising above the two lateral corolla lobes and a third, three-lobed, central lip is a tubular structure that contains the fused filaments of the five stamens; the anther tubules are brush-like grayish structures at the downturned tip. The stigma runs up the center of this tube; it remain hidden for a time behind a pair of lips for a time, then the style elongates and emerges from the tip of the tube as a two-lobed stigma. The reproductive structures are precisely positioned to touch (and transfer pollen with) the head of a hummingbird drinking nectar from the flower. The fruit is a small, hemispherical, 1/4-1/2" capsule hidden in the remnants of the calyx. Nothing else in Illinois looks even vaguely like cardinal flowers.

Lobelia

Lobelia cardinalis

cardinal flower [Blooms: Jul-Sep]

Great blue lobelia's flower spike is 0.5-2' long, densely covered by blue-violet flowers with white stripes. individual flowers are about 1" across, the apex angled upwards, with a green, very hairy calyx with five long, narrow teeth and the bell-shaped corolla a tube that splits distally into in an upper and a lower lip, each with long white hairs on their outer surfaces. The lower lip consists of three lance-shaped, descending lobes with white patches near their bases; the upper lip has two lobes that flank on either side a cylindrical structure (five bluish stamen filaments fused with and surrounding the style) with a down-turned tip (the stigma) surrounded by brush-like anther "beards". The flower stalk and calyx are green and densely hairy. Like most lobelias, great blue lobelia contains toxic alkaloids that can produce serious symptoms; keep pets away. This species is unlikely to be confused with any other. If mystified by the flower structure, see http://iowaplants.com/flora/family/Campanulaceae/lobelia/l_siphilitica/Lobelia_siphilitica.html.

Lobelia

Lobelia siphilitica

great blue lobelia [Blooms: Aug-Oct]