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Peppergrass (aka, Virginia pepperweed) is a weedy, 1.5' tall, rather bushy plant. The flower spikes (racemes) are 2-4" long with tiny (<1/8") white apical flowers forming a larger inflorescence. The flowers have four oblong green or tan sepals with a white edge, half the length of the petals, alternating with four white, triangular petals. There are two stamens with yellow anthers and a stubby (0.2 mm tall) style on a green ovary. Below the flowers, the flower spike is covered with 1/8" wide seedpods on (relatively) long stalks, reminiscent of a bottlebrush; the seedpods are oval with an apical notch (much like half-sized versions of field pennycress (Thlaspi arvense) seedpods) containing two seeds. This species is native to the U.S. The stubby cylindrical inflorescences are and the triangular petals alternating with shorter sepals are diagnostic and distinguish pepper grass from field peppergrass (Lepidium campestre).

Lepidium

Lepidium virginicum

peppergrass [Blooms: Oct-Nov]

Round-headed bush-clover present stout, tall (2-5') green columns in the middle of open habitats. The stem is unbranched below the midpoint (except at the inflorescences), round in section, grooved, and densely covered in white hairs. At the apex of the main stem and on some of the side stems are slightly elongated balls of flowers 3-5" long and half as wide with numerous clover-like white flowers nearly hidden among leafy bracts; brown flowerheads and stalks may persist through winter. Each clover-like flower is about 1/4" wide and 1/2" long with five petals, one large vertical upper petal ("standard") and two perpendicular side petals ("wings") are visible; the other two petals (forming the keel) are hidden from view by the wings. There are ten stamens, all but one with their filaments fused together, and a single style with a small stigma. The petals are white with a patch of reddish-purple near the junction of the three visible petals. The fruit is a fuzzy pod less than 1/4" long containing a single seed. Round-headed bush-clover is a perennial with a tap root that may go down two meters into the soil.

Lespedeza

Lespedeza capitata

round-headed bush-clover [Blooms: Aug-Sep]

Ox-eye daisy is an aggressive plant that was introduced to the U.S. in the 19th century and is now thoroughly naturalized. Flowerheads occur singly at the apex of the stem on a long flower stalk. The flowerheads are about 1.5-2" across with 15-35 brilliant white, oblong ray florets and 120-200 yellow disc florets in a central, flattened disc about 3/4" across. The ray florets are fertile (they bear pistils with a split stigma) while the disc florets have both pistils and stamens. The disc florets are tubular with five tiny lobes at the apex, five stamens, and a single style with a bifurcated tip. The underside of the flower has numerous bracts in 2-4 layers; the bracts are green with purple to brown edges that outline each bract.

Leucanthemum

Leucanthemum vulgare

ox-eye daisy [Blooms: May-Jul]

False Solomon's seal's stem terminates in a flattened panicle of hairy, whitish-green stalks about 3-5" long and 2" across bearing 20-80 white flowers. The individual flowers are bright white, about 3/16" across with six narrow, spreading, strap-like tepals that are shorter than the stamens, six stamens with triangular white filaments and pale yellow or cream-colored anthers, and a single central style on top of a globose ovary. The fruit is a spherical berry, initially whitish in color, turning mottled red and later bright, translucent-red (like a currant) when ripe. It can be a bit tricky to distinguish false Solomon's seal from starry false Solomon's seal, especially early in the spring when the plants are small. Two features help: the inflorescence of false Solomon's seal is two to three the size (in linear dimensions and number of flowers) as that of starry false Solomon's seal, and the stigma of false Solomon's seal is two- or three-lobed and sessile (rests directly on the ovary), while the stigma of starry false Solomon's seal is elevated on a long style (as long as the stamens). In Jackson Park, false Solomon's seal is very tolerant of woodland habitats.

Maianthemum

Maianthemum racemosum

false Solomon's seal [Blooms: Apr-Jun]

Starry false Solomon's seal stems terminate in a 1-4" long cluster (a raceme) of up to 20 white flowers, each ~3/8" across. Individual flowers have six narrow, spoon-shaped tepals longer than the stamens, six stamens with creamy-yellow anthers, and a vase-shaped pistil with a stout style. The fruit is a 1/4" diameter berry, initially green with dark stripes, becoming bright red with maturity. The leaves of Maianthemum stellatum are much narrower than those of Maianthemum racemosum (false Solomon's seal) or Polygonatum biflorum (Solomon's seal) and has an overall appearance more like a lily than a Solomon's seal (false or smooth). It can be a bit tricky to distinguish false Solomon's seal from starry false Solomon's seal, especially early in the spring when the plants are small. Two features help: the inflorescence of false Solomon's seal is two to three the size (in both linear dimensions and number of flowers) as that of starry false Solomon's seal, and the stigma of false Solomon's seal is two- or three-lobed and sessile (rests directly on the ovary), while the stigma of starry false Solomon's seal is elevated on a long style (as long as the stamens). In Jackson Park, false Solomon's seal is very tolerant of woodland habitats; starry false Solomon's seal prefers sunnier habitats like open grasslands.

Maianthemum

Maianthemum stellatum

starry false Solomon's seal [Blooms: Apr-May]

Common mallow flower stalks arise from the leaf axils. They are 1/2-1" long, attached to one to three, 1/4-1/2" wide flowers. Individual flowers have a green calyx with five pointed, triangular lobes half the length of the petals; white or pale violet squared-off petals with a shallow notch and pale violet lines; the 12-15 stamens make a bumpy, white globe around the 12-15 fused pink styles in the middle of the flower, with the inner surface of the style tips as the stigmas. The fruit is a round, flattened ovoid with radiating lines (the edges of the carpels) around a dimpled center, nestled in the remains of the calyx. Some people claim that the fruit resembles a wheel of cheese (thus one of the common names); it reminds me more of a miniature gourd. All parts of this plant are edible.

Malva

Malva neglecta

common mallow [Blooms: May-Oct]

Wild chamomile stems terminate in a daisy-like flowerhead, 1-2" across. Flowerheads consist of 10-25 white, fertile (pistillate) ray florets that tend to droop slightly and a gumdrop-shaped central mass of 250-550+ yellow disk florets with both male and female reproductive structures. Individual disk florets are tubular. Behind the flowerhead are one to three series of light green, lance-shaped bracts with membranous edges. Wild chamomile can be distinguished from similar plants like ox-eye daisy (Leucanthemum vulgare) by its multiply-pinnate, slender lobes leaves and the fact that the flowerhead is actually hollow; when crushed they produce a pleasant, fruity fragrance. Wild chamomile is closely related to pineapple weed (Matricaria discoidea) but the two can't be confused.

Matricaria

Matricaria chamomilla

wild chamomile [Blooms: May-Jun]

White sweetclover flowers occur in spikes along 2-6" long flower stalks that arise from upper leaf axils and on the terminal upper stems. Individual flowers are small (~1/4-3/8" long), have a tubular, light green calyx with five teeth, and five white petals in the typical pea-like configuration (a single standard on the top — here, hood-like over the keel, two lateral wings, and a pair of petals fused to form a medial keel that is perpendicular to the banner). The stamens and style are hidden within the keel. Yellow sweet-clover is nearly identical to white sweet-clover (Melilotus albus) except for flower color, but blooms slightly earlier. In both yellow and white sweet-clover, the "teeth" along the distal margins of the leaflets are actually sharply-pointed extensions of the secondary (pinnate) veins. A similar extension of the central vein occurs in yellow sweet-clover but is ABSENT in white sweet-clover, permitting discrimination between the two species even when not in bloom if the vein extensions are present elsewhere on the leaflet.

Melilotus

Melilotus albus

white sweetclover [Blooms: Jun-Sep]

Glade mallow flowers fill the entire apex of the plant in multiple clusters (panicles). Each plant produces only male or only female flowers. Both male and female flowers are about 1/2-3/4" across with 1" long pedicels, a short, light green, tubular calyx bearing five broad teeth around the edge, and five white petals. To this general pattern, male flowers add 16-20 stamens fused basally; the free ends are separated into filaments bearing tan or pink anthers. Female flowers add to the basic flower a compound style with 6-10 white, twisted, thread-like branches. The fruits are round, fist-like clusters of wedge-shaped segments (up to 10), each containing a single seed. Glade mallow occurs in only seven states. It is listed as "vulnerable" in Illinois, Iowa, Wisconsin, and Ohio; it is "imperiled" in Indiana and Minnesota and critically imperiled in Maryland. Glade mallow prefers moist habitats. Populations in Jackson Park have been noticeably expanding over the last few years; be grateful.

Napaea

Napaea dioica

glade mallow [Blooms: Jun-Aug]

Fragrant water lily flower stalks, like the leaves, develop directly from the rhizomes. Flowers are 3-6" across; they have four greenish-white sepals that rest on the water's surface; 15-40 brilliant white (occasionally pink) petals in multiple series; 35-120 stamens with bright yellow anthers distributed around the inner circumference of tthe flower; and a central stigmatic disc on the floor of the flower at the base of the stamens. Flowers open and close daily. The fruit is 1-2" long and globoid; its stalk bends downward so the fruit develops underwater. After the tiny seeds (~1/16-1/8") are released, they float for some time, dispersed by wind and water currents, then sink to the bottom of the water body where they germinate.

Nymphaea

Nymphaea odorata

fragrant water-lily [Blooms: May-Aug]

Smallflowered gaura is a spindly, usually unbranched plant that gets 2-6' fall, much of that the flower spike. The stem is round in section, light- to reddish-green, and covered with fine hairs. The leaves are alternate, 2-5" long and 1/4-1" across, lance-shaped, and sessile. The apex of the stem gives rise to a narrow spike of small flowers 1/2-2.5' long. Flowers open from the base of the spike towards the tip with relatively few open at any one time. Individual flowers are about 1/4" across. They consist of four sepals reflected back along the elongated, cylindrical, light-green or red flower stalk/ovary, four spreading white or pink petals, eight stamens, and a long style with a X-shaped (or four-lobed) stigma. The flowers are said to open in the evening and close in the morning. The seed capsules develop from the ovary; they are about 9 mm long. The flowers and flower spike of smallflowered gaura are quite distinctive and unlikely to be confused with any other species.

Oenothera

Oenothera curtiflora

smallflowered gaura [Blooms: Jul-Sep]

As the name suggests, biennial gaura is a biennial. In its first year biennial gaura develops a dense, flat basal rosette; in its second year, multiple stems shoot up from the basal rosette, branching frequently and reaching 3-7' tall. The flower spikes are 4-8" long with flowers opening from the bottom to the top. Each flower is open and airy, 1/2" long and wide, with four white or pink, spoon-shaped, petals deployed around the upper quadrant of the flower; eight long white stamens with yellow anthers and a single long white style with a yellow, X-shaped, stigma emerge at right angles to the fan of petals. Behind the petals is a red or green, hairy, tubular calyx with four sepals whose tips are reflected backwards. The fruits lie on the flower spikes behind the open flowers; they are diamond- or spindle-shaped with a flat-to-conical tip and four large ribs running longitudinally and are covered with fine hairs. Oenothera gaura is almost indistinguishable from large-flowered gaura (Oenothera filiformis, a.k.a., Gaura longiflora), but the latter has larger flowers and hairs on the stems that are curled against the stem (as opposed to straight hairs); I've not identified large-flowered gaura in Jackson Park.

Oenothera

Oenothera gaura

biennial gaura [Blooms: Jul-Sep]

Aniseroot tends to be an understory plant, 1-2.5' tall. Individual flowers are tiny (1/8"), grouped in distinct compound umbels, each with several narrow, lance-shaped bracts with hairy margins at the base of the umbel. The flowers have a tiny green calyx without sepals, five white petals with incurled tips, five stamens with white anthers, and a pistil with a divided white style (longer than the petals — about 2 mm). The fruit is a hairy, narrow, arched seedpod about 1" long; the two styles (and, less commonly, petals and stamens) persist at the tip of the seedpod for part of the maturation. Aniseroot is very similar to sweet cecily (Osmorhiza claytonii), but aniseroot has more flowers (8-16) in each umbel than does sweet cecily (4-7) and the two styles in the flower are short and dumpy (shorter than the petals) in sweet cicely and much longer (longer than the petals) in aniseroot. The stems and stalks (except the umbel stalks) are densely covered with fine, short hairs or no hairs in aniseroot, long, spreading hairs in sweet cecily. The crushed leaflets smell like — surprise! — anise in aniseroot.

Osmorhiza

Osmorhiza longistylis

aniseroot [Blooms: Apr – Jun]

Cowbane is a spindly, sparse plant 2-5' tall. At their apex, the stems produce shallowly dome-shaped compound umbels 3-5" across of 10-25 umbelletes of 10-20 small white flowers each. Individual flowers are about 3 mm across; each has a short calyx, five white petals with notched tips, five stamens with white anthers, and a central greenish or white ovary with two styles. The fruit is a elongate (1/4" long), flattened oval with wings on the flattened edges, longitudinal stripes/ribs and, initially, with the remnants of the two styles at their tips; when mature it splits, releasing two seeds. Cowbane prefers wet soils. As you might suspect from the name, it is toxic if eaten.

Oxypolis

Oxypolis rigidior

cowbane [Blooms: May-June]

Mature wild quinine plants are 2-3' tall. On the flowering stalks (and the side branches) are flat topped clusters of white, button-like flowerheads about 3/8" across. (The Illinois Wildflowers website considers them "similar to a head of cauliflower.") Flowerheads are composed of 15-35 disk florets, often with blackish, club-like stamens poking out; the 5-6 ray florets bear a tiny, cup-shaped petal and a pistil with a bifurcated stigma. No other wildflower in Illinois has flowerheads anything like wild quinine; common and widespread in Jackson Park.

Parthenium

Parthenium integrifolium

wild quinine [Blooms: May-Aug]

Ditch stonecrop is native to North America; its range includes the majority of the states in the U.S. and the provinces in Canada. It is a small (1-2' tall) plant with green or red stems, usually unbranched. Cymes of flowers 1-3" across arise from the upper stems, each cyme with 2-4 spreading flowering stalks; flowers are restricted to only one side of the flower stalks. Individual 1/4" flowers are yellowish-green to white, have five spreading, green sepals, ten stamens with cream-colored or yellow-orange anthers, and five beaked carpels, each with a single style and a green stigma; petals are completely absent. (The carpels look rather like a teapot with no handle and a very wide spout, or like a "duck" wine decanter. Look it up.) The carpels become the seed capsules; they turn bright red when mature. Ditch stonecrop prefers wet habitats (like ditches). It is completely unrelated to biting stonecrop (Sedum acre).

Penthorum

Penthorum sedoides

ditch stonecrop [Blooms: Aug-?]

At the apex of the stems and branches of wild dill are compound umbels of small white flowers; the umbels are about 6" across and have 12 umbellets that are widely spaced from each other. An umbellet is about 1" across and contains 7-21 flowers. Individua flowers are about 3 mm (1/8") across, consisting of 5 small, triangular, green sepals; 5 petals, each notched at the tip; (ideally) 5 stamens with white anthers; and a hairless ovary formed from two fused carpels, each with a short style. The stamens are fragile and often fall off, so there may be less than five stamens present. The fruit is an elongated schizocarp 3-5 mm long with a longitudinal groove that splits to release laterally flattened, wingless, brown to black seeds. Often, the remnants of the styles persist at the apex of the fruit.

Perideridia

Perideridia americana

wild dill [Blooms: Jun]

Waterpepper is a rather spare plant, 1-2' tall which needs close observation to be appreciated. 2-7" long spikes of minute flowers, only a few of which are open at any one time, terminate the upper stems; the flower spikes often nod or droop. Each greenish-white flower is ~1/8" long with five tepals covered with glandular pits (see below), green towards the base, brilliant white at the tips, 4-6 white stamens, and 2-3 white styles. The flowers never open very far. P. hydropiper is distinguished by (usually) reddish stems and the presence of tiny glandular pits (often pale yellow or brown, and only visible with magnification) on the greenish portions of the tepals. Cultivated varieties of waterpepper have been eaten in Japan and Europe, but the wild form produces a variety of oils that can cause skin (including the oral mucosa) irritation and swelling.

Persicaria

Persicaria hydropiper

waterpepper [Blooms: Aug-Sep]