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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]

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]

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]

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]

Riverbank grape's flowers develop in 5" long, drooping, cylindrical or pyramidal panicles opposite the leaves of new branches (but skipping every third leaf). The flowers are greenish-yellow and are best described as skeletal; they may be either unisexual or (rarely) perfect (both male and female reproductive organs functional). The male and female unisexual flowers usually both occur on the same plant, either in separate or mixed clusters; both male and female flowers are 1/8" across or less, with a minute calyx and five green to yellowish petals that quickly fall off. Male flowers have five very long, pale, erect stamens around a button-like center; female flowers have an ovary with a short style and five short, sterile stamens, often contorted. The fruit are .... grapes — a round berry, 1/4-1/2" across containing 1-4 seeds, initially green but turning blue-black as it matures, often with a white bloom on the skin. You know, grapes. The fruit of riverside grape is often sour until after a frost, then becomes more "sweet/tart" to the tongue. Riverside grape is subject to parasitism by the grape filbert gall midge (Ampelomyia vitiscoryloides), an insect whose larvae produce large, very hairy, conical galls at leaf nodes. This gall midge is restricted to the eastern half of North America; it was first described by Alpheus Spring Packard, Jr. in 1869.

Vitis

Vitis riparia

riverbank grape [Blooms: [May-Jun]

Common cocklebur produces a spike-like raceme of compound flowerheads, shorter than the leaf petioles, that arises from the axils of each upper leaf and from the tip of the central stem. Each raceme produces exclusively male flowerheads in its upper parts and exclusively female flowerheads in the lower regions. The male flowerheads are about 1/4-3/4" across, elevated on a short pedicel on top of 1-3 series of white floral bracts. Each of the approximately 20 tiny, brownish-green staminate florets (nominally disk florets) consist of a tubular 1-2 mm long corolla; a minute, non-functional ovary; and five stamens with fused filaments (like a tree trunk) but with their white anthers free, positioned in a ring like a little palm tree or, possibly, a hand. The staminate florets quickly shed their pollen and drop off. The female flowerheads (also nominally disk florets) are 3/4-1.5" long and two-thirds as wide, stalkless, each (usually) containing two female florets nearly enclosed by floral bracts covered with curly white hairs that have a bur-like appearance from the dense, hooked prickles covering their surface. At the tip of the flowerhead are two spines, longer and much stouter than the prickles, each with a hole from which protrudes the divided style of a female floret. There is no corolla in the female florets. The florets are wind pollinated, and their styles quickly wither away after fertilization. Each female floret produces a single, oblong, dark gray to black seed 3/8-1/2" long, tapering to a point at each end and covered by dark membranes, all buried in the bur-like bract. The female flowerhead stiffens through the autumn, turns brown, and overwinters. The seeds are highly poisonous, containing toxic diterpene glycosides. One of the contained seeds germinates the following year; the other delays germination for two years. Common cocklebur prefers wet, sandy soils.

Xanthium

Xanthium strumarium

common cocklebur [Blooms: Sep-?]

The tips of the upper stems of heartleaf alexanders produce 2-3" wide compound umbels of 7-15 umbellets, each with 10-20 tiny yellow flowers. The central flower of each umbellet is sessile; the rest have short pedicels (a diagnostic character of the genus). Each 1/8" wide flower consists of five yellow petals that remain curled, five stamens with yellow anthers projecting through the spaces between the petals, and two styles. The fruits are a ribbed capsule with a flat top from which the remnants of the styles project. Heartleaf alexanders is restricted to northeastern Illinois, where it is uncommon; it is usually found in drier habitats than its much more common relative, golden alexanders (Zizia aurea).

Zizia

Zizia aptera

heartleaf alexanders [Blooms: Apr/May–?]

The tips of the upper stems of golden alexanders produce flat to slightly rounded compound umbels 2-3" across with about a dozen umbellets of tiny, golden-yellow flowers. Each umbellet has about 20 flowers; the central flower is sessile (or nearly sessile) while all the other blooms in the umbellet are on short stalks (pedicels), a character of the genus. Each 1/8" wide flower consists of an insignificant calyx, five yellow petals that are persistently incurled, five stamens with yellow anthers projecting through the spaces between the petals, and two styles. The fruits are a ribbed (not winged) 2 mm long capsule with a flat top from which the remnants of the two styles project. Golden alexanders prefers full to partial sun and is tolerant of a range of habitat quality. The yellow-flowered variety of meadow parsnip (Thaspium trifoliatum var. aureum) is very similar to golden alexanders but has basal leaves that are simple rather than trifoliate compound, but I have not seen meadow parsnip in Jackson Park. John Hilty (www.illinoiswildflowers.info) warns that "Golden Alexanders should not be confused with Pastinaca sativa (Wild Parsnip), which is a weedy Eurasian biennial. The latter is taller, blooms later, and has more leaflets in each compound leaf." Wild parsnip DOES occur in Jackson Park, but it is relatively rare, twice the size of golden alexanders, has robust, strongly ribbed stems, and a large, flattened, winged fruit. Heartleaf alexanders (Zizia aptera) is also very similar, but only the uppermost leaves are compound; all the lower and middle leaves are simple and heart-shaped.

Zizia

Zizia aurea

golden alexanders [Blooms: Apr/May–?]