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Purple meadow-rue is a native perennial that is listed as "vulnerable" in Illinois. The species is found in most of the lower 48 states in the U.S. but is notably absent from states on the Atlantic and Pacific coasts (however, it is present along the Gulf of Mexico). Purple meadow-rue is dioecious — some plants produce only staminate (male) flowers, each with around a dozen stamens; other plants bear only pistillate (female) flowers, each with about ten pistils. The male flowers are the showier of the two. Petals are absent (the plant is wind-pollinated). Both the narrow, whitish-grey, thread-like pistils and the yellow-green stamens (with pale yellow anthers) droop from 4-5 light green sepals (that may drop off). Fertilized female flowers develop a single, spindle-shaped fruit that is 1/4" long, elongated, sharply pointed with a remnant style, 4-6 raised ribs, and slightly concave along one side. The fruit is initially green, turning brown with maturity. Early meadow-rue (Thalictrum dioicum) is similar to purple meadow-rue but has light purplish-green stems and leaves with 3-9 (typically five) rounded lobes and long petioles on the upper leaves.

Thalictrum

Thalictrum dasycarpum

purple meadow-rue [Blooms: May-Jun]

Early meadow-rue's main stem terminates in a panicle up to a foot long and wide; each branch in the panicle has a corymb of about five flowers at its tip. Early meadow-rue is dioecious — some plants produce only staminate (male) flowers, each with 10+ stamens; other plants bear only pistillate (female) flowers, each with up to 15 pistils. Both male and female flowers droop from their stems, but the male flowers have a longer droop than do the female flowers. Both male and female flowers are about 1/2" long and 1/4" across with 4-5 pale green sepals with white margins (which often fall off). Neither male nor female flowers have petals; pollination is via the wind. Fertilized female flowers produce ellipsoid, dry seeds that are pointed at both ends; the surface bears strong ribbing. Early meadow-rue prefers shady woodlands. It has more lobes on its leaves (usually 3-5), and the lobes are more rounded than purple meadow-rue (Thalictrum dasycarpum), the other Thalictrum species in Jackson Park, does (2-3 pointed lobes).

Thalictrum

Thalictrum dioicum

early meadow-rue [Blooms: Apr-May]

Immediately above the terminal stem leaves or leaflets of rue anemons is an umbel of one to six 1/2-1" flowers on 1.5" long pedicels. Each flower has 5-10 white or pinkish-white, petal-like sepals and a striking green center made of 1-16 pistils surrounded by 7-30 stamens with yellow anthers. There are no true petals. The fruit is a cluster of 5-15 strongly ribbed spindles about 8 mm long, pointed at both ends; each contains a single seed. Rue anemone prefers woodlands with dappled sunlight in the spring but tolerates shade in the summer months. The leaflets/leaves of rue anemone are similar to the leaflets of purple meadow-rue (Thalictrum dasycarpum), but you'll never confuse the two; purple meadow-rue blooms six weeks later and is seven feet taller than rue anemone.

Thalictrum

Thalictrum thalictroides

rue anemone [Apr – May]

Erect hedge-parsley's main stem and side stems give rise to umbels 1.5-2" across of 10-20 umbellets of flowers. Each flower is about 1/8" across consisting of five white petals (often markedly unequal in size), and a creamy white center surrounded by five pink to white stamens. The fruit is an 1/8" long oval covered in hooked hairs to aid in bur-like dispersal; it contains two seeds. (The fruit of common hedge-parsley (Torilis arvensis) has straight or only slightly curved hairs, not hooked, but the hairs are barbed.)

Torilis

Torilis japonica

erect hedge-parsley [Blooms: Jun-Jul]

Fuzzy flower stalks about 1" long arise from the leaf axils of low hop clover. The flowerheads are roughly spherical, lemon yellow, and about 1/2" across comprised of 20-40 pea-like florets with five petals; each floret is about 4 mm long. The upper petal (the standard) on each floret is conspicuously grooved and forms a hood over the two petals forming the keel; two lateral petals flank the keel. Fertilized florets form tiny seedpods that are shorter than the keel. The flower color and foliage of low hop clover are very similar to black medic (Medicago lupulina), but the standard on black medic is not grooved and sits perpendicular to the keel.

Trifolium

Trifolium campestre

low hop clover [Blooms: May-Aug]

Alsike clover is an exotic perennial native to Europe. Despite the scientific name ("hybridus"), it is not a hybrid. (Linnaeus thought it was a hybrid of red and white clover. It isn't.) The plant is 6-24" tall, with occasional branches along the stems. One- to three-inch-long flower stalks arising from the leaf axils terminate in a flowerhead 1/2-3/4" across; florets tend to be white on the top of the flowerhead and reddish-purple to pink on the bottom, but may all be reddish. Individual florets are 1/4" long with five petals in a pea-like bloom. They have a sharply pointed standard (the major vertical petal, perpendicular to the keel), two petals that make up the keel, and two lateral petals that flank the keel. Ten stamens and a single pistil are hidden inside the keel. Unlike red clover (T. pratense) and white clover (T. repens), there are no pale chevron-shaped markings on the leaflets.

Trifolium

Trifolium hybridum

alsike clover [Blooms: May-Jul]

The upper stems of red clover end in 3/4-1" wide pinkish-purple (not actually red) flowerheads, usually with 1-3 leaflets or a compound leaf and some pointed bracts immediately below the bloom. The florets are tubular modification of a typical pea-like flower with five petals; the upper petal (the standard) is slightly longer than the other four petals and has a slightly pointed tip. Red clover is easily identified by the pinkish-purple flowerheads, the leaflets inserted just below the flowerheads, and the white chevrons on the leaflets.

Trifolium

Trifolium pratense

red clover [Blooms: Apr-Jun]

White clover's hairless, leafless flower stalks are up to 3" long. They emerge directly from the horizontal stems and grow perpendicular to the ground, producing a single globular 3/4" wide flowerhead at their tips. The flowerheads are all white, consisting of 20-50 pea-like florets. The florets are tubular, consisting of a green calyx with five long, narrow teeth, and five white or pinkish-white petals (a standard, two petals making the keel, and a pair of lateral petals flanking the keel). White clover is similar to alsike clover (T. hybridum), but that species usually has some pink in the flowerheads and never has white chevrons on the leaflets.

Trifolium

Trifolium repens

white clover [Blooms: May-Jun]

Clusters of lowbush blueberry's flowers develop on the previous year's twigs. The flowers are about 1/4" long, urn- or bell-shaped, nodding, white, and waxy. The flowers contain a short, green calyx with five teeth; a short, tubular corolla that is pinkish white or white with five triangular, recurved lobes around its margin; ten stamens with reddish brown anthers recessed behind the margin of the corolla and clustered around the style; and a single style whose stigma extends right to the margin of the corolla. Fertilized flowers are replaced by approximately 8 mm diameter berries, initially green but turning dark blue with a whitish bloom as they mature. (I.e., they look — and taste — like blueberries.)

Vaccinium

Vaccinium angustifolium

lowbush blueberry [Blooms: May]

The apex of the common mullein plant is a club-shaped flower spike 6-24" long, covered with scattered light-yellow flowers each 3/4" across. Individual flowers have five hairy, green sepals; five pale yellow petals (the lower two slightly larger than the upper three); five stamens with reddish-orange anthers; and a single green style with a heart- or disc-shaped stigma. The upper three stamens are shorter than the other two stamens and covered with white or yellow hairs; the lower two stamens are longer and largely hairless. The fruit is an oval, two-celled seed capsule, brown when mature, each cell filled with numerous (25-150) tiny orange to brown seeds. Common mullein is immediately recognizable and impossible to confuse with any other local plant.

Verbascum

Verbascum thapsus

common mullein [Blooms: Jun-Aug]

Purpletop vervain flowers occur in dense, flat-topped clusters 1-3" across. Individual flowers are about 1/4" (5-6 mm) long and 8-9 mm long. The flowers contain a short, tubular, hairy calyx with five teeth; a pinkish purple, tubular corolla with five spreading lobes that have notched tips; four stamens which do not extend beyond the throat of the flower; and a pistil with a single style. The fruit is four nutlets, cupped in the remnants of the calyx as they mature.

Verbena

Verbena bonariensis

purpletop vervain [Blooms: Sept]

Prostrate vervain stems produce dense spikes of flowers at their tips. Beneath each flower is a 3/4" long, narrow bract with long, whitish hairs; the bracts make up the erect or sprawling flower spike (6" long, 3/4" across), with blooming flowers at the tip and fruits maturing below. Individual flowers are about 1/8" across, with a narrow, very hairy, basal calyx extending into five sharply pointed lobes, and a narrow, tubular corolla that abruptly flares into five rounded lobes ("petals") surrounding a white or greenish-white throat; the upper two lobes are slightly smaller than the lower three. Both the calyx and corolla are the same color whether light blue, purple, or pink. Hidden in the throat of the corolla are four stamens with yellow anthers and a short style. The fruit consists of a capsule containing four nutlets that is nestled in the remains of the calyx. This plant is a pioneer in highly degraded habitats that is especially fond of cracks and crevices — despite its weedy appearance, prostrate vervain is a native species. In spite of the tiny size of its anatomical characters, this is a relatively straightforward plant to confidently identify from the hairy stems, leaves, and flower spikes and the tiny, lavender apical flowers.

Verbena

Verbena bracteata

prostrate vervain [Blooms: Jun-Aug]

Flower spikes about 5" long cover the top of the blue vervain plants; they are densely covered with floral buds and flowers that bloom from the bottom of the spikes sequentially to the top. Below the open flowers are maturing fruits. Individual flowers are tubular, 1/4" long and across, with a grayish green to dark red, hairy calyx sporting five narrow teeth; a tubular, purplish-blue corolla twice the length of the calyx that abruptly flares into five equal, ovate lobes ("petals"); four recessed stamens; and a single, short style. The throat of the flower is "bearded" (occluded by light blue filaments extending to the middle of the opening) which hides the reproductive organs. This is the only vervain with a blue (not deep violet/lavender) color; other species are pink, white, or lavender. The fruit consists of four 2 mm long nutlets held in the remnants of the calyx. Blue vervain might be confused with hoary vervain, but the latter has larger (2x), lavender (not purplish-blue) flowers (with one lobe/petal notched and two larger than the other three), and ovate to egg-shaped (not lance-shaped) leaves that are sessile (not on petioles 1/2" long or longer). Blue vervain is especially common along the margins of the lagoons of Jackson Park.

Verbena

Verbena hastata

blue vervain [Blooms: Jul-Sep]

Hoary vervain flower spikes are 1-8" long; they are crowded with buds and bluish violet to lavender flowers 1/2" across that open sequentially from the bottom of the spike to the top; below the open flowers are maturing fruits. Individual flowers are tubular, 1/2" long and across, with a grayish green to reddish-purple, hairy calyx sporting five narrow teeth. The tubular, bluish violet to lavender corolla, twice the length of the calyx, abruptly flares into five ovate lobes ("petals"); the two lateral lobes are the largest, while the lower lobe(s) has/have a notched tip. Hidden in the tubular corolla are four recessed stamens with yellow anthers and a single, short green style. The fruits consist of four nutlets held in the remnants of the calyx.

Verbena

Verbena stricta

hoary vervain [Blooms: Jun-Jul]

White vervain produces numerous 6" long, widely spaced flower spikes, each covered by tiny (1/8" wide) white flowers sparsely distributed along the length of the flower spike. Individual flowers consist of a hairy, tubular green calyx with five lance-like teeth and a curved, tubular corolla that abruptly flares into five short, rounded, brilliant-white lobes ("petals"). The throat of the flower is "bearded" (occluded by white filaments extending to the middle of the opening), hiding four stamens with greenish anthers, a green style, and a two-lobed stigma. The upper (more apical) two lobes of the corolla are slightly smaller than the other three (like prostrate vervain) and the tip of the lowermost lobe of the corolla is notched (like hoary vervain), but you're not likely to confuse white vervain with any other Verbena. The fruit is four oblong nutlets nestled in the remnants of the calyx.

Verbena

Verbena urticifolia

white vervain [Blooms: Jun-Sep]

The tip of a smooth ironweed central stem bears a cluster (a corymb) up to 4" in diameter of magenta composite flowerheads that is quite densely packed in a flat or (sometimes) domed inflorescence. The branches of the inflorescence (but not the stem) may be lightly fuzzy with small hairs. Each flowerhead is 3/4" across and contains 10-30 magenta disk florets, each with five lobes and a very prominent, divided style with curled tips (the stigmas) and five stamens appressed to the base of the style; ray florets are completely absent. The bracts that cover the underside of the flowerheads are green or purplish brown, flattened, appressed, and rounded at their tips, imbricated like fish scales with white, cobwebby hairs around their edges. The fruit is a naked seed with an attached tuft of white hairs (actually, scales). To sort out the Jackson Park ironweeds: (1) if both leaves and stem are densely covered with fine white hairs, the leaves are about 3-4 times longer than wide, and each flowerhead has more than 30 disk florets, it's Missouri ironweed (V. missurica). (2) If both leaves and stems are hairless, there are less than 30 disk florets, and the leaves are narrow (typically a half inch or less; about 6-10+ times longer than wide), it's smooth ironweed (V. fasiculata). (3) If the stems and leaves have only short hairs, there are less than 30 disk florets, and the leaves are about 2" wide and 4-6 times longer than wide, it's tall ironweed (V. gigantea).

Vernonia

Vernonia fasciculata

smooth ironweed [Blooms: Jun-Sep]

Tall ironweed's inflorescence is a flat-topped panicle arising from the tip of the central stem; it is 6-16" across, open and spreading. There are 10-30 disk florets in a tall ironweed flowerhead. The base of the flowerhead is covered by several series of dark colored, broadly oval appressed bracts (phyllaries), often with fine hairs around their edges. The disk florets have tubular, trumpet-like corollas with five recurved lobes; ray florets are absent. Tall ironweed has a much more "open" composite flowerhead than the other ironweeds in Jackson Park, with the trumpet bases of the disk florets easily visible. The fruits are naked, gray or brown, bullet-shaped seeds with a tuft of both short and long tawny or pale purple hairs. To sort out the Jackson Park ironweeds: (1) if both leaves and stem are densely covered with fine white hairs, the leaves are about 3-4 times longer than wide, and each flowerhead has more than 30 disk florets, it's Missouri ironweed (V. missurica). (2) If both leaves and stems are hairless, there are less than 30 disk florets, and the leaves are narrow (typically a half inch or less; about 6-10+ times longer than wide), it's smooth ironweed (V. fasiculata). (3) If the stems and leaves have only short hairs, there are less than 30 disk florets, and the leaves are about 2" wide and 4-6 times longer than wide, it's tall ironweed (V. gigantea).

Vernonia

Vernonia gigantea

tall ironweed [Blooms: Jul-?]

At the tip of a Missouri ironweed stem, a corymb of composite flowerheads (the inflorescence) is produced. The stems of the inflorescence are also covered in fine white hairs and usually reddish brown in color. Individual flowerheads are magenta and rayless; ray florets are completely absent. Flowerheads contain 32-60 disk florets, each 1/2-3/4" across, which have rounded or broadly angled bracts (phyllaries) with sharp tips, dull green or reddish brown in color, that are layered like fish scales around the base. To sort out the Jackson Park ironweeds: (1) if both leaves and stem are densely covered with fine white hairs, the leaves are about 3-4 times longer than wide, and each flowerhead has more than 30 disk florets, it's Missouri ironweed (V. missurica). (2) If both leaves and stems are hairless, there are less than 30 disk florets, and the leaves are narrow (typically a half inch or less; about 6-10+ times longer than wide), it's smooth ironweed (V. fasiculata). (3) If the stems and leaves have only short hairs, there are less than 30 disk florets, and the leaves are about 2" wide and 4-6 times longer than wide, it's tall ironweed (V. gigantea).

Vernonia

Vernonia missurica

Missouri ironweed [Blooms: Jul-Oct]