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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]

Large-flowered trillium's single flower sits on a 1-3" long flower stalk; the flower is 3-4" across and leans to one side (but doesn't droop). The flower consists of three green, lance-shaped sepals with rounded bases, three white (pinkish in older flowers) petals with wavy edges, six stamens with golden yellow anthers, a central white ovary, and three styles fused basally but with separated, dull-yellow stigmas. The fruit is a six-angled, globose capsule, about 1/2" long, that is initially green but darkens as it matures; it splits open to release the seeds. The seeds carry an attached oily, fleshy food reward (an elaiosome) and are dispersed by ants which inadvertently deposit the seeds in their nests to take advantage of the reward. Large-flowered trillium prefers shady environments like woodlands and is slow to mature — it can take several years for a sprout to produce flowers.

Trillium

Trillium grandiflorum

large-flowered trillium [Blooms: Apr-May]

The apical flowers of prairie trillium have three green sepals that are reflexed so they point down, three maroon petals, six maroon stamens with dark purple anthers incurved toward the center of the flower, and three purple styles with divergent stigmas hidden from view by the stamens. The fruit is a green, six-angled, ovoid berry 1" long; the seeds have an oily food appendage (an elaiosome) that encourages ants to carry them away. Despite the name, prairie trillium does not occur on prairies; it is a shade-loving, woodland plant like the other local trillium, large-flowered trillium (Trillium grandiflorum). Prairie trillium is superficially similar to toadshade (Trillium sessile), but in toadshade the sepals are spread (perpendicular to the stalk), not recurved (parallel to the stalk, pointed down). In addition, the leaves of toadshade are sessile (no petiole) and rarely have the troutlily-like mottling on the leaves that is seen on prairie trillium. The stamens of toadshade are yellow, not maroon. Toadshade does occur in Illinois, but it is less common, and I have yet to see it in Jackson Park.

Trillium

Trillium recurvatum

prairie trillium [Blooms: Apr-May]

The stalk of narrow-leaved cattails terminates in two spikes of unisexual flowers separated by a distinct gap (at least 1/2", usually several inches). The upper (staminate) spike is narrowly cylindrical, up to 8" long and 1/2" across, light yellow or light brown, and densely covered with staminate flowers (each bearing a single quartet of pollen grains) and numerous hairs. The lower (pistillate) spike is also cylindrical, up to 12" long and 3/4" across, brown or reddish brown in color, and densely covered with pistillate flowers and numerous hairs. The fertile pistillate flowers consist of a 1 mm long bractlet and a 1 mm long stipe that includes the ovary and a single, slender style; both are surrounded by several hairs. (Flora of North America (http://dev.floranorthamerica.org/Typha_angustifolia) and the Jepson Herbarium (https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=47466) have nice illustrations.) The flowers are wind pollinated. Some pistillate flowers are infertile and lack ovaries. Fertilized flowers produce a naked seed attached by a stalk to a tuft of white fibers; the seeds are dispersed by the wind. Narrow-leaved cattail can grow on wet soil or in water up to a foot deep.

Typha

Typha angustifolia

narrow-leaved cattail [Blooms: Jun-Jul]

In common cattail, staminate (male) flowers are located in a spike on the top of the cattail less than a half inch above the spike of female flowers (typically the spikes abut). The upper (staminate) spike is narrowly cylindrical, up to 12" long and 3/4" across, yellow or light brown, and densely covered with staminate flowers (each bearing a single quartet of pollen grains) and numerous hairs. The lower (pistillate) spike is also cylindrical, up to 18" long and 1.5" across, greenish or blackish brown in color, and densely covered with pistillate flowers and numerous hairs. The staminate spike withers soon after the pollen is released; the pistillate spike persists through the autumn. The fertile pistillate flowers consist of a 4 mm long stipe that includes the ovary and a single, slender 2.5 mm long style with a flattened stigma; both are surrounded by several hairs. (The Jepson Herbarium (https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=47466) has a nice illustration.) The flowers are wind pollinated. Some pistillate flowers are infertile and lack ovaries. Fertilized flowers produce a naked seed attached by a stalk to a tuft of white fibers; the seeds are dispersed by the wind. Common cattail can grow on wet soil or in water up to 1.5 feet deep. It often reproduces vegetatively from horizontal rhizomes buried in the soil/mud. The narrow-leaved cattail (Typha angustifolia) has narrower leaves (1/2"), smaller flower spikes (both in length and diameter) and the male flower spike is located a few inches above the female flower spike.

Typha

Typha latifolia

common cattail [Blooms: Jun-Aug]

Slender stinging nettle plants are dioecious (unisexual) with male (staminate) and female (pistillate) flowers on separate plants. Flowers occur in knobby clusters (panicles) that arise from the leaf axils. Neither pistillate nor staminate flowers have any petals. Staminate flowers have four light green, identical sepals cupping four short stamens. Pistillate flowers also have four sepals but two sepals are narrowly lance-shaped, about a millimeter long, and free, alternating with two sepals that are 1.4-1.8 mm long and cupped around the ovary; styles are absent but the single stigma is long and feathery. The fruit is a flattened, oval to egg-shaped, seed less than 1/16" long. Stinging nettles (aka, tall nettle, slender stinging nettle) have a complicated biogeographic history. According to USDA Plants (https://plants.sc.egov.usda.gov/) and ITIS.gov, the subspecies "Urtica dioica gracilis" is native, while the subspecies "Urtica dioica dioica" is an exotic that is native to Europe and Asia. Thus, you may see "stinging nettle" listed as either "native" or "exotic." Both subspecies are perennials, and both occur in Illinois, although "gracilis" is most common; most features are the same for both subspecies. Wikipedia says these subspecies are actually separate species, an opinion based on a 2014 paper in Phytotaxa (162: 61-83) that analyzed molecular characters; Kew Garden's Plants of the World Online (https://powo.science.kew.org/) and iNaturalist also accept Urtica gracilis as a valid species. I've chosen to use "Urtica gracilis" here if only to avoid further proliferation of long scientific names in this presentation.

Urtica

Urtica gracilis

slender stinging nettle [Blooms: Jul-Aug]

Each side stem of yellow bellwort produces a single, elongate bell-shaped flower at its tip. The flowers droop on their stem-like pedicels (about 1 " long) such that they open downwards and are often partially hidden by the leaves. Each flower is 1-2" long and consists of six yellow tepals twisted along their length (often with greenish bases), six white stamens with elongated yellow anthers, and a pistil with a three-lobed stigma. The fruit is a three-section capsule that looks (vaguely) like three fat triangles with oval bases, stuck base to base to base. Seeds are freed when the capsule splits. Seed dispersal is added by the attraction of ants to a fleshy, nutrient-rich appendage (an elaiosome) on the seed; the ants carry the seed back to their nest where they eat the elaiosome and abandon the seed.

Uvularia

Uvularia grandiflora

yellow bellwort [Blooms: Apr-May]

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 top of the wingstem plant is a dome (a panicle) of coarse-looking flowerheads. Each flowerhead is 1-2" across, with 2-10 yellow, oblong, drooping petals, 1/2-1" long that are derived from the sterile ray florets. Some 40-60+ yellowish-green, tubular disk florets project in all directions in a hemisphere of widely-spaced, robust, bud-like blunt cylinders, the tips of the disk florets. When receptive to pollen, the disk florets bear a protruding style with a bifurcated, curling pair of stigmas (likened by one source to a "pince-nez" — a pair of eyeglasses on a handle); the five stamens and their flattened, black anthers are appressed to the body of the style. The fruit is a teardrop-shaped seed with a pair of thin wings and two short, robust, spiky awns. Immature seeds are green; the seeds (and seedheads) turn brown when mature.

Verbesina

Verbesina alternifolia

wingstem [Blooms: Jul-Oct]

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]