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American bittersweet side branches occasionally produce panicles of flowers (up to 6" long) at their tips. Male flowers are about 1/4" wide with five light green petals with jagged or undulate margins, five green sepals, and five stamens with yellow anthers and a narrow style rudiment.

Celastrus

Celastrus scandens

American bittersweet [Blooms: Jun-Jul]

Common hackberry flowers may be staminate (male), pistillate (female), or perfect (both), all on the same tree. Flowers are about 1/4" across and bloom before the leaves open, often high in the tree (thus, I have no pictures yet). All flowers are wind-pollinated, yellowish-green with 4-6 spreading sepals joined at their bases; there are no petals. Male flowers have 4-5 stamens with green or yellow-brown anthers; female flowers have a green ovary with a large two-part, densely fuzzy style like an umbrella beneath the ovary. Perfect flowers have both.

Celtis

Celtis occidentalis

common hackberry [Blooms: Apr-May]

Sandburs are no one's friend. They are a form of grass with light green culms, round in section, up to 2.5' long; they are mostly covered by the sheaths of the alternate leaves. Each culm and upper branches (if any) terminate in a 4" long (3/4" across) raceme of 4-20 spiky burs. Each 1/4" diameter bur (excluding the spines) consists of 2-3 spikelets, each containing a fertile flower recognizable only by the stamens or styles protruding from the tip of the spikelets. The flowers are wind pollinated. This is the only sandbur in Illinois, so identification is easy (if not always painless).

Cenchrus

Cenchrus longispinus

sandbur [Blooms: Aug-?]

Lamb's quarters produces inconspicuous star-shaped, yellow-green flowers, <1/8" across, sessile on flower stalks in round, tight clusters; the flowers have no petals, five stamens with yellow anthers, and a single divided style at the tip of a round, green ovary, all cupped in a five-lobed, mealy-white, calyx. The flowers are wind-pollinated and can aggravate hay fever symptoms.

Chenopodium

Chenopodium album

lamb's quarters [Blooms: Jul-Sep]

American hazelnut flowers. The male inflorescence is a cylindrical catkin that appears in the fall on the most recent year's twigs and then overwinters; in the spring, the catkin elongates (to 2-4" long) and the male flowers (consisting of two tiny bracts and four stamens) open to release their pollen. The female inflorescence looks like a small bud protected by bracts that is located at the branch tip or in leaf axils; it contains several pistillate flowers seen only as red styles/stigmas protruding from the tip of the "bud."

Corylus

Corylus americana

American hazelnut [Blooms: Mar-Apr]

Winged pigweed flowers are whitish-green, sessile, and 1/16" across; the flowers have five inward-curving sepals that cover the ovaries, five stamens, and a flattened ovary with 2-3 styles. Flowers may contain only a pistil or both a pistil and stamens; if the latter, the creamy-yellow anthers are prominent.

Cycloloma

Cycloloma atriplicifolium

winged pigweed [Blooms: Jul-Aug]

Broad-leaved helleborine's inflorescence is a 4-12" long raceme with 15-50 flowers, all on one side of the flower stalk. Individual flowers are 1/2-3/4" wide. The petals are greenish-purple with the lower petal forming a pale red bowl; behind the petals, the three sepals are pale green with purple stripes. (The sepals are as long as the petals, as are the bracts below the flowers' stalks.) The fruit is a hairy capsule ~1/2" long, and egg-shaped. Broad-leaved helleborine prefers woodlands.

Epipactis

Epipactis helleborine

broad-leaved helleborine [Blooms: Jul]

Winged euonymous' younger stems and branches have geen bark and 2-4 cork-like "wings" (thin plates whose plane lies in a radius of the branch). Clusters of 1-3 flowers arise from leaf axils; individual flowers are about 1/3" (8 mm) across with four green sepals, four yellowish-green petals, four stamens, and a green central dome which bears the single pistil with a reddish, multilobed stigma. Four-lobed seed capsules become dark red or purple at maturity; they split to expose 1-4 reddish-orange arils.

Euonymus

Euonymus alatus

winged Euonymus [Blooms: May-Jun]

Seaside sandmat cyathia (cup-like reproductive structures typical of euphorbs) develop between pairs of leaves, typically one cyathium with a short reddish stalk per pair of leaves. On the rim of the cyathium are four to six red nectar glands; each nectar gland alternates with a narrow, elongate lobe. In the center of the cyathium is a female flower with a three-lobed, light green ovary topped by a tripartite style; the flower sits on a stout pedicel that elongates and curves as it matures. Between the central female flower and the rim of the cyathium are several male flowers, each consisting of a single stamen. Seaside sandmat prefers beach habitats around the Great Lakes and along the Atlantic coast.

Euphorbia

Euphorbia polygonifolia

seaside sandmat [Blooms: Jul-Sep]

Black bindweed flowers develop in singletons or pairs from the leaf axils or directly from the stem. Flowers are 1/8-1/4" long; they have 3-5 greenish-white, white, or light purple petal-like tepals, the outer three tepals with a ridge or keel down the midline on the outer surface. Six to eight stamens with purple anthers surround fused green styles with a dome-shaped stigma in the middle of the flower; the flower usually opens only partially (like a tulip). The fruit is three-sided, with a tubercle-covered surface, about 1/4" long, black when fully mature. Black bindweed is very similar to climbing false buckwheat (Fallopia scandens).

Fallopia

Fallopia convolvulus

black bindweed [Blooms: Jun-Jul]

Climbing false-buckwheat stems are round, angular, or ridged in section, often with hairs on the ridges. Racemes of flowers arise from the leaf axils; the flower stalks are usually vertical, 3-8" long and bear both erect flowers and drooping fruits. Individual flowers are greenish-white, about 3/16" across have eight stamens with white anthers and an ovary bearing a tripartite style; the thee outermost tepals (petals) have obvious wings, unsually with an undulating margin; the inner two tepals are simple ovals. The fruit (~3/8" long) has a greenish center with three white wings; the 3 outer tepals with enlarged wings enclose the seed. (The fruit resembles a much-enlarged version of the fruit of curly dock (Rumex crispus).) Climbing false-buckwheat is very similar to black bindweed (Fallopia convolvulus) but is far more common in Jackson Park.

Fallopia

Fallopia scandens

climbing false-buckwheat [Blooms: Aug-Sep]

Green ash is dioecius; each tree produces only either male (staminate) or female (pistillate) flowers (which are wind pollinated). The flowers open in mid-spring, before the leaves emerge. Male flowers are produced in compact clusters that envelop short sections of the second-year twigs. Each staminate flower is yellowish green to greenish purple and less than 1/8" (3 mm) across, consisting of a tiny, four-lobed, tubular calyx and a pair of purplish stamens. Petals are absent. Female flowers are also produced on the second-year twigs, in this case in small panicles. Each female flower consists of a tiny four-lobed, tubular calyx and a pistil with a single, long style; again, petals are absent. Fertilized flowers are replaced by panicles of drooping, spatula-shaped, winged seeds 1-2.5" long and 1/4-1/3" wide that have an ellipsoid swelling at one end containing the seed and a single elongated, membranous wing with a rounded or notched tip. When released in the autumn, the greenish to tan fruits spin around the seed, reducing their rate of fall so they can be carried greater distances by the ambient wind. Green ash is tolerant of shading so can grow in mature forests; it prefers moist soils and can tolerate some flooding.

Fraxinus

Fraxinus pennsylvanica

green ash [Blooms: May?]

The white, waxy, drooping flowers of greater snowdrop are born on leafless scapes (flower stems). The flowers consist of three white outer tepals and three white inner tepals; the outer tepals have distinctly narrowed bases while the inner tepals are more rectangular, usually with a green blotch at their base and tip or a bold green stripe running from base to tip. (Common snowdrop flowers have a single, restricted blotch of green on their inner tepals.) There are six stamens with yellow anthers recessed inside the edge of the inner tepals; the stamens form a ring around the style. The style is slender, cylindrical, and slightly longer than the stamens. The fruit is a spherical to ellipsoid green capsule that splits into thirds when ripe, releasing the seeds.

Galanthus

Galanthus elwesii

greater snowdrop [Blooms: Mar-Apr]

Snowdrop is the earliest blooming flower in Jackson Park (late February); individual blooms can persist for about a month. The bell-shaped flowers hang down on a thin peduncle from a smooth, hairless flower stalk up to 10" long. The flowers have six oval, half-spread tepals; the three outer tepals are white with rounded tips, the three inner tepals are white with green, notched tips and green stripes on the interior surface. There are six stamens with yellow-orange anthers and a single greenish-white style. The fruit is a green, egg-shaped enlarged ovary with a flattened distal tip that dangles form the peduncle. Snowdrops usually exist in a given spot because of a prior deliberate cultivation (in some recorded cases, up to 60 years earlier) and rarely pose an invasion threat; they typically propagate from bulbs. The source of the snowdrops in Jackson Park is unknown.

Galanthus

Galanthus nivalis

snowdrop [Blooms: Feb-Mar]

Cream gentian the leaves are olive-green, lance-shaped with a pronounced fold along the midvein, 3" long and 2" across, and clasp the stem. Although most leaves are opposite (in pairs), the leaves just below the flowers occur in a whorl of three. The flowers are mostly apical, some version of white or cream, tubular, with the petal's veins outlined in green, about 1-2" tall and 3/4" across, and oriented near-vertically. The five petals remain tightly appressed, with only a small opening where their apices meet; the five stamens and pistil with a bifurcated stigma are usually hidden from view. Bumblebees are the primary pollinators.

Gentiana

Gentiana alba

cream gentian [Blooms: Jul-Oct]

Honey locust is a native tree that grows 50-100' tall; it has a single trunk 2-3.5' in diamater. The bark on the trunk is gray-black, divided into plates with peeling edges; the bark of twigs and branches is smoother, brown, and hairless. New shoots are green and fuzzy. Leaves are alternate and invariably compound, either even-pinnate (i.e., the leaflets are all paired, with no terminal leaflet) all 6-14" long with 5-11 pairs of leaflets, or bipinnate (i.e., the primary divisions of the compound leaf are themselves pinnate) with 4-7 pairs of even-pinnate leaflets 6-14" long, each with 5-11 pairs of leaflets. Leaflets are 3/4-1.5" long and about a third as wide. Thorns, both simple and branched, are usually present, especially on the trunk, but a thornless form exists; newly formed thorns can be a brilliant red. Flowers are present in 2-5" long racemes, usually as either male or female, but perfect flowers may be present. The flowers are small (1/8-1/4" across) and greenish-yellow. The fruit is a 6-14" long, dark-brown seedpod.

Gleditsia

Gleditsia triacanthos

honey locust [Blooms: May-Jun]

Kentucky coffeetree produces a single 1.5-3' diameter trunk that, with its branches, can reach heights of 60-90'. The trunk bark is rough, scaly, gray or gray-brown; the bark on the branches is smoother, gray; the bark on the twigs is gray or brown with whitish lenticels. The leaves are alternate, bipinnate-compound, with 5-9 pairs of pinnate leaflets, each with 6-14 pairs of subleaflets. The entire compound leaf can be 3' long and 2' across, the largest leaf of any native tree in Illinois. Individual trees may produce only male flowers, only female flowers, or "perfect" flowers with both male and female organs flowers; the flowers develop as racemes on terminal branches fairly high in the crown shortly after the tree leafs out in the spring. Flowers are about 3/4" long and 1/2-5/8" across with a narrow, tubular calyx bearing five thick, narrow, sepals, and five narrow, greenish-white petals, slightly wider than the sepals, and a central column about as long as the petals that contains the reproductive organs. The male and perfect flowers have 10 fertile stamens (in alternating long/short pairs) in the central column; the female and perfect flowers have a fertile ovary and a single style contained in the central column. The calyx, sepals, and petals are all densely wooly with short hairs. The fruit is a stubby, reddish-brown seedpod 3-6" long and 1.5-2" across, somewhat flattened but less so than the fruits of honey or black locust. The seeds are brown, VERY hard, oval, and about a half inch long and across; they are toxic when raw but can be eaten after roasting.

Gymnocladus

Gymnocladus dioicus

Kentucky coffeetree [Blooms: May-Jun]

Heuchera richardsonii

Heuchera

Heuchera richardsonii

common alumroot [Blooms: May – Jun]