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The upper stems of hairy aster give rise to 2 foot long, 1.25 foot wide panicles with a central rachis that produces spreading or ascending primary branches and smaller secondary branches that bear the flowerheads. Each flowerhead is 1/2-3/4" across with 15-35 white ray florets and 20-40 yellow disk florets that turn reddish purple or brown with age. The bracts (phyllaries) that surround the base of the flowerhead are present in 4-5 layers; they are 3 mm long and light green with a long, darker green tip. The edges of the phyllaries are often rolled under and thus may appear needle-like. The phyllaries and the bracts attached to the panicle branches both have a tiny spine at their tip. (Note: heath aster (S. ericoides) also has such spines but has smaller flowerheads, broad, blunt phyllaries with a larger spine, and the hairs on the stems are either appressed to the stem or are ascending.) The fruits are 1-1.15 mm long, tan colored, dry seeds with 3-4 longitudinal ribs and a tuft of white hairs. After blooming is completed, rosettes of 3" long, 1" wide, spoon-shaped basal leaves develop and persist through the winter into the spring, but wither away before blooming begins again.

Symphyotrichum

Symphyotrichum pilosum

hairy 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]

The upper stems and branches (some arising from upper leaf axils) of white arrowleaf aster terminate in 6-18" long panicles of flowerheads; the panicles are 2-3 times longer than wide. Each flowerhead is 1/2-3/4" across with 8-15 pistillate, white (rarely pale lavender) ray florets and 10-15 perfect (both stamens and styles present) disk florets. The disc florets are initially yellow but turn pink or light purple with age such that the flowerheads with yellow disk florets are often in the minority on the plant. The individual disk florets strike me as being larger than on many asters. The phyllaries (bracts) covering the base of the flowerhead are narrowly lance-shaped, usually hairless, dark green in the middle tapering to narrow, stiff, green to purplish tips. The fruits are 2 mm long, purplish-brown dry seeds with longitudinal ribs and a tuft of hairs at one end. White arrowleaf aster is similar to Drummond's aster (Symphyotrichum drummondii) but is less hairy and has distinctly different phyllaries. Among asters with white flowerheads, only white arrowleaf aster has heart-shaped leaves. (Other asters with heart-shaped leaves typically have blue to violet flowers.)

Symphyotrichum

Symphyotrichum urophyllum

white arrowleaf aster [Blooms: Aug/Sep – ?]

The inflorescences of common comfrey are nodding cymes or racemes of flowers that arise from the tips of the stems and the lateral branches. The flowers are bell-shaped, about 1/4" across and 1/2-5/8" long. Each flower has a hairy, green calyx with five lance-like teeth that is half the length of the corolla; a purple, pink or white funnel- or bell-shaped corolla with five small, recurved lobes at its lip; five stamens that do not extend past the margin of the corolla; and a pistil with a single white style that barely protrudes past the corolla margin. The fruits are a cluster of four, 4-5 mm long, nutlets nestled in the remnants of the flower calyx; the nutlets are dark brown or black when mature, oval and slightly flattened at one end. The remnants of the style protrude from the center of the fruit. Extracts of common comfrey are sometimes sold as herbal remedies but be aware that the plant is mildly toxic; it contains pyrrolizidine alkaloids that can be absorbed through the skin or gastric system and may cause (potentially fatal) liver toxicity and may be carcinogenic. Comfrey products for internal use or for use on open wounds are banned in the U.S. by the F.D.A. Supplements containing common comfrey probably should be avoided.

Symphytum

Symphytum officinale

common comfrey [Blooms: Apr-Jul]

Some upper stems produce compound umbels at their tips made of tiny, yellow flowers; the umbels are very open (they remind me of a fireworks burst), up to 4-7" across with 12-15 umbellets of about a dozen flowers. Individual flowers are about 1/8" across with five tightly furled, yellow petals; five stamens emerging from between the incurled petals and widely spreading with pale yellow anthers; and two styles. Sepals are absent. The flowers tend to be either pistillate (stamens reduced or absent) or staminate (styles reduced or absent), but a few perfect flowers occur. Yellow pimpernel prefers dry habitats on a slope at the edge of woods.

Taenidia

Taenidia integerrima

Yellow pimpernel [Blooms: May-?]

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]

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]

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]

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]