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Common boneset's upper stem and branches bear clusters 2-8" across of white flowerheads. Each flowerhead is about 4-6 mm across consisting of ~15-20 dull white disk florets (ray florets are absent); florets have a tubular corolla with five triangular lobes at the apical end and a long, bifurcated style surrounded at its base with a brown column of five stamens with purplish anthers. Ironically, "common" boneset is less common than late boneset or tall boneset in Jackson Park.

Eupatorium

Eupatorium perfoliatum

common boneset [Blooms: Jul-Aug]

Late boneset's inflorescence is a flat-topped or shallowly-domed panicle with numerous flowerheads. Individual flowerheads are composed of 12-15 greyish-white disk floret (ray florets are absent) about 1/4" long with a tubular corolla with five small, triangular apical lobes and a long white bifurcated style extending well out from the floret surrounded by five black stamens. Leaf venation, lack of leaf hairs, and and smaller flowerheads (~5-8 florets) distinguish tall bonset (E.altissium) from late boneset (E. serotinum; 12-15 florets).

Eupatorium

Eupatorium serotinum

late boneset [Blooms: Aug-Oct]

Flowering spurge "flowers" are deployed in an open, flat-topped inflorescence (panicle); individual "flowers" are 1/4-3/8" across, a cup-like, five-lobed cyathium (unique to euphorbs) containing the five white "petals" (actually white bracts), a green ring of nectar glands around the base of the "petals," and the stamens or styles. Male flowering spurge cyathia have three stamens, each with a white filament and a yellow anther; female flowering spurge cyathia have both an ovary with a tripartite style with six stigmas, and three (sterile?) stamens. (If you're confused about the architecture of cyathia, see seaside sandmat (Euphorbia polygonifolia) for a clearer example.) After fertilization, the fruit develops as a unmistakable three-celled, bulbous green capsule on a short stalk in the middle of the original flower with the remnants of the style at its tip.

Euphorbia

Euphorbia corollata

flowering spurge [Blooms: Jun-Oct]

Sweet Joe-Pye weed's inflorescence is a domed or pyramidal panicle. The flowerheads are whitish-pink to pinkish-purple and strikingly variable in color between plants, 1/4-3/8" long, consisting of 4-7 disk florets, each with a whitish-pink to purplish-pink tubular corolla with five lobes at its apex, two long, thin white styles extending well outside the floret and five stamens fused to the corolla about halfway up its length; there are no ray florets. The flowerheads make a domed (rather than flat) cluster at the apex of the plant. The bracts (phyllaries) around the base of the flowerhead are pale pink.

Eutrochium

Eutrochium purpureum

sweet Joe-Pye weed [Blooms: Jul-Aug]

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]

Wild strawberry always show a terminal marginal tooth of each leaflet that is shorter (and often narrower) than the teeth on either side, a diagnostic character. Clusters of white flowers are borne on 5" long, hairy peduncles. Individual flowers are on 3/4" long (again hairy) pedicels. The flowers are 1/2-3/4" across; there are five green, narrow, pointed, hairy sepal-like bracts; five hairy, lance-shaped sepals; five oval white petals longer than either the bracts or the sepals; and variable reproductive organs depending on whether the flower is male (least common, with ~20 yellow stamens and anthers), female (with a central yellow dome of pistils), or "perfect" (both male and female, with the appropriate organs). Fruits are familiar, if small (1/2") strawberries, bright red when ripe, with the seeds sequestered in sunken pits so the surface is mostly smooth; the fruit hangs beneath - and is tightly embraced by - the sepals and sepal-like bracts, is edible, and is tasty, if a bit tart. Wild strawberry superficially resembles mock (Indian) strawberry in its foliage and (superficially) fruit, but wild strawberry has white flowers, not yellow; the fruit of wid strawberry hangs below the sepals rather than resting above the sepals as in mock strawberry; and the seeds of wild strawberry lie embedded in the surface of the fruit rather than protruding as in mock strawberry.

Fragaria

Fragaria virginiana

wild strawberry [Blooms: Apr-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]

Gallant-soldier (aka, small-flowered galinsoga) flowerheads are about 1/4" across; they have 4-8 (usually 5) ray florets with a single minute (about 2x2 mm) white petal notched to produce two or three lobes; the ray florets are distributed around the circumstance of the disc. There are 15-50 golden yellow, tubular disc florets with five short triangular lobes at their apex. Both ray and disc florets are fertile; the ray florets are pistillate while the disc florets are perfect (both pistils and stamens). The fruit (a cypsela) consists of a black, conical seed suspended beneath about five off-white, papery, fringed scales that act as a parachute. Gallant-soldier is very similar to galinsoga (Galinsoga quadriradiata); the latter has larger flowerheads and ray floret petals.

Galinsoga

Galinsoga parviflora

gallant-soldier [Blooms: Aug-Sep]

Galinsoga (aka, Peruvian daisy or shaggy soldier) flowerheads are small (1/4" across) with 4-8 (usually five) widely separated 2.5 mm long, white ray florets with three teeth at their tips. The 15-35 disc florets are yellow. Both ray and disc florets are fertile; the ray florets are pistillate while the disc florets are perfect (both pistils and stamens). The fruit (a cypsela) consists of a black, conical seed suspended beneath about five off-white, papery, fringed scales that act as a parachute. A poisonous plant (Tridax procumbens) with nearly identical flowers (but distinctly different leaves) is (luckily) restricted to FL and TX in the U.S. so not likely to show up in Jackson Park. The name Galinsoga ciliata, sometimes still used for Galinsoga quadriradiata, is invalid (ITIS); according to the USDA Plants database, C. ciliata has been superceded by either G. quadriradiata or G. urticifolia.

Galinsoga

Galinsoga quadriradiata

galinsoga [Blooms: Jun-Oct]

Cleavers' flowers are tiny (2-3 mm across), star-shaped, with two green carpels covered with hooked hairs joined at the base of the flower; four white, pointed petals; four stamens; and two styles. The fruit is a spherical capsule formed from the carpels, covered with stiff, hooked hairs, each carpel containing a single seed.

Galium

Galium aparine

cleavers [Blooms: Apr/May-?]

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]

Carolina crane's-bill flowers are small (about 1/4-3/8" across), in small clusters on stubby pedicels. Each flower contains five dull-green, very hairy, lance-shaped sepals with long, scarlet-tipped awns on the tips, five white to pinkish-lavendar petals shorter than the sepals, ten stamens with tan anthers, and five stamens fused at their bases. The fruit is spherical with a very long beak divided longitudinally into five sections; when ripe (the fruit turns bright red) , the beak splits violently into five strips attached to each other at their distal ends, flinging the seeds far from the parent plant. Carolina crane's-bill has white to pinkish flowers with sepals longer than the petals; cut-leaved crane's-bill (Geranium dissectum) has deep pink to purple flowers with sepals the same length as the petals.

Geranium

Geranium carolinianum

Carolina crane's-bill [Blooms: May-Jun]

White avens blooms slightly later than rough avens (Geum laciniatum); it reaches about the same size (1.5-2.5' tall). The flowers are 1/2" diameter; they have five green sepals that are white-edged, pointed, and the same length or (usually) shorter than the petals; five white, rounded petals with a narrow attachment; and numerous (25-120) stamens surrounding a dome-shaped mass of green styles about a third the diameter of flower. The sepals initially lie under the petals but later become reflexed back parallel to the flower peduncle.The spherical fruit is covered with long, hooked spines (actually, persistant styles) that help the seeds stick to fur and clothing. White avens is distinguished from rough avens (G. lacinatum) by their flower stalks covered with short, fine hairs (rather than long, coarse hairs) and sepals that are shorter than the petals.

Geum

Geum canadense

white avens [Blooms: Jun-Jul]

Rough avens flowers are 1/2" wide, with five triangular green sepals longer than the petals, five cream or white, circular petals with narrow attachments, and numerous (25-120) stamens with (initially) cream-colored anthers distributed around a central gumdrop-shaped mound of green carpels with long styles. The fruit is more or less spheroid, 3/4" across, and covered with long, hooked spines (actually, persistant styles) that help the seeds attach to clothing and animal fur. Note that some sources identify this species as Geum virginianum, but G. virginianum is the cream avens according to the USDA Plants database; Hilty (ILW) lists G. virginianum as "restricted to southern Illinois". The two species are very similar, but G. lacinatum has very hairy stems and hairless receptacles and G. virginianum has smaller flowers (1/3") with cream-colored petals dwarfed by the sepals. Rough avens is distinguished from white avens (G. canadense, also found in Jackson Park) by petals that are shorter than the sepals and their very hairy flower stalks; rough avens also blooms earlier than whte avens.

Geum

Geum laciniatum

rough avens [Blooms: June]

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]

Although stickseed flowers are tiny (1/8"), they have the ususal complement of parts — a hairy green calyx with five long, narrow teeth that alternate with the petals; five rounded white (or light blue) petals (actually lobes of the corolla tube); five arching, scale-like structures surrounding the opening to the tube; five stamens largely hidden inside the corolla tube; and a four-lobed ovary with a short style, similarly hidden inside the corolla tube. The fruits are globular, <1/4" across, densely covered with hooked prickles; they are purportedly the most difficult of such "sticktights" to remove from clothing.

Hackelia

Hackelia virginiana

stickseed [Blooms: Jul-Aug]