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The tips of the stems of goat's-rue give rise to 2-3" long racemes of buds and flowers. The unmistakable, bicolored pea-like flowers are about 1/2-3/4" wide and long, creamy white or yellowish on the vertical petal (the "standard") and rosy-pink on the lateral wings and the keel. (A total of five petals.) The flowers consist of a short, tubular calyx with five teeth, five petals in a pea-like configuration, 10 stamens (nine with fused filaments, one free from its midpoint) with small yellow anthers, and a single pistil with a tiny terminal stigma. Both stamens and pistil are enclosed by the keel. The seedpods are 1.5-3" long, cylindrical, slightly flattened beans spreading laterally from the flower spike; these, too, are (densely) silky-hairy. The seedpods are initially light green but turn brown with maturity. They split along the symmetry plane of the seedpod and the valves develop a spiral curl to release the seeds. Goat's-rue prefers sandy habitats. The long, woody roots contain rotenone, a compound that is toxic to fish and insects; it inhibits ATP production and disrupts mitochondrial function by blocking the electron transport chain. It would not be a good idea to suck on or ingest the roots of goat's-rue.

Tephrosia

Tephrosia virginiana

goat's-rue [Blooms: Jun-Jul]

American germander flower spikes develop on the tips of the stems, with flowers opening from the bottom of the spike towards the (elongating) tip. Individual flowers are small (about 1/3-3/4"), white or lavender, with a bell-shaped, hairy calyx; an upper lip reduced to two lance-like, vertical lateral lobes that insure pollinators remain beneath the single long, arching single and 3-4 stamens with purple anthers; and a greatly expanded lower lip (a landing pad for pollinators) covered with purple spots. The fruit consists of four nutlets that are nearly fused together, nestled in the remnants of the calyx (which clearly shows the asymmetrical teeth — bottom two smaller than upper three). The nutlets are greenish white when immature, becoming redder and coarsely pitted as they mature. American germander is distinguished from other members of the mint family (Lamiaceae) by the very small upper lip and enlarged lower lip. Related species of Teucrium contain a toxic compound that causes liver damage in animals; for safety's sake, I would avoid herbal remedies that include American germander.

Teucrium

Teucrium canadense

American germander [Blooms: Jun-Aug]

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]

Field pennycress's central stem and the upper side stems produce racemes of flowers at their tips. The flowers bloom at the tip of the raceme, which continues to elongate to 3-8" long and to produce new buds; the prominent, disk-shaped fruits develop lower on the raceme. Individual flowers are about 1/8-1/4" across on a 1/2" pedicel; there are four green sepals with whitish edges, four white, oval petals, six yellowish-green stamens (three on each side of the flattened ovary), and a single short style. The fruit is a 1/2" wide flattened, winged disc with a distinct U-shaped notch at the apex; the fruits are borne on the flower pedicels, which spread perpendicular to the stem. Each seedpod has two compartments, each compartment containing several dark brown seeds. Other mustards have long, cylindrical seedpods; the nearly-circular seedpod of field pennycress is unique among Jackson Park mustards. Young field pennycress plants are edible but become very bitter at flowering. Cows that feed on field pennycress produce "tainted" milk that tastes like garlic.

Thlaspi

Thlaspi arvense

field pennycress [Blooms: Apr-Jun]

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]

Ohio spiderwort's flowers and buds occur in a cluster, each cluster on a hairless flower stalk (pedicel) with a pair of long, leaf-like bracts at its base at the apex of the plant. Individual flowers are about 1-1.5" across, with three green, oval sepals offset from the petals; three rounded blue-violet petals; six stamens with blue filaments and bright yellow anthers; a single blue style with a small white stigma; and fine, thread-like, violet hairs radiating out from the stamen and style bases in the center of the flower. The seed capsules are 4-8 mm long, ovoid, with three distinct compartments. The mature seed capsule splits into three sections, each releasing 3-6 oblong, strongly ribbed, brown seeds. The flowers open early in the morning but close in the afternoon (later on cloudy days). Ohio spiderwort is the commonest spiderwort in Illinois and the only Tradescantia species to occur in Jackson Park; the very similar Virginia spiderwort (Tradescantia virginiana) can be distinguished from Ohio spiderwort by its hairy flower stalks (pedicels).

Tradescantia

Tradescantia ohiensis

Ohio spiderwort [Blooms: Apr-Sep]

Western goat's-beard's stems terminate in a single flowerhead, with the stem strongly swollen beneath the flowerhead. Individual flowerheads are pale lemon yellow and about 2" across. Between 50-180 ray florets are present; disc florets are absent. A series of about 13 sharply pointed, narrow bluish-green bracts (significantly longer than the outer ray florets) surround the base of the flowerhead. The outer ray florets (the "petals") are much longer than the inner ray florets. All ray florets have an outer tip of the "petal" decorated with five small teeth. Near the base of the ray florets is a composite reproductive structure consisting of a single style, bifurcated at its tip, and five stamens with black anthers closely appressed to the middle of the style. The flowerheads open in the morning but close in the afternoon; the flowerheads sometimes track the sun like a sunflower. Fertilized florets produce a long, narrow, naked seed densely covered with small teeth; the seed is attached to a plume of fine white hairs (like a dandelion). The seed head looks like a giant version of a dandelion seed head. Western goat's beard is very similar to yellow goat's beard (Tragopogon pratensis) but prefers drier habitats; the latter has only eight bracts (rather than 13) surrounding the flowerhead and the bracts are the same length (not longer) than the outer ray florets.

Tragopogon

Tragopogon dubius

western goat's-beard [Blooms: May-Sep]

Yellow goat's-beard stems produce a long naked stalk from their tips that bears a single flowerhead. Individual flowerheads are bright yellow and 1-2.5" across. Between 50-180 ray florets are present; disc florets are absent. A series of about eight sharply pointed, narrow green bracts (the same length or shorter than the outer ray florets) surround the base of the flowerhead. The outer ray florets (the "petals") are much longer than the inner ray florets. All ray florets have an outer tip decorated with five small teeth. Near the base of the ray florets is a composite reproductive structure consisting of a single yellow style, bifurcated at its tip, and five stamens with black anthers closely appressed to the middle of the style. Fertilized florets produce a long, narrow naked seed; the seed is attached to a plume of fine white hairs (like a dandelion). The seed head looks like a giant (3" across) version of a dandelion seed head. Like Tragopogon dubius, it's an exotic, but at least it's less aggressive. Distinguish yellow goat's beard (T. pratensis) from western goat's beard (T. dubius) by flower color (bright yellow vs. pale yellow), foliage color (green vs. bluish green, number of floral bracts (8 vs. 13), leaf shape (tips curled vs. tips straight), and length of the floral bracts (same as petals vs. much longer than petals).

Tragopogon

Tragopogon pratensis

yellow goat's-beard [Blooms: May-Aug]

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]

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]