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The axils of the middle and upper leaves of woodland goldenrod produce small clusters of 1-12 flowerheads; the stem tip may also develop a small (3" long, 1.5" across) panicle of flowerheads. Individual flowerheads are tiny (3 mm) consisting of 4-5 ray florets with yellow, oblong-elliptical "petals" and 3-6 disc florets with golden yellow, tubular corollas with five tiny lobes. At the base of each flowerhead are three overlapping series of light green, elongate-elliptical bracts (phyllaries). The fruit is a small, bullet-shaped seed 1-2 mm long with a tuft of white hairs 3-5 mm long. In Illinois, only woodland goldenrod and broad-leafed goldenrod (Solidago flexicaulis) produce clusters of flowerheads from the axils of the middle and upper leaves; however, the latter has coarsely serrated leaves with petioles and should be easy to distinguish from woodland goldenrod.

Solidago

Solidago caesia

woodland goldenrod [Blooms: Sep-Oct]

A panicle of flowering stems develops at the top of a Canada goldenrod plant; the flowering stems arch away from the main stem, their upper sides covered with yellow flowers. The panicle may be pyramidal (at least as long as wide) to spreading (wider than long); it is sometimes club-shaped on smaller plants. Individual flowers are 1/8-1/4" across, with 8-14 yellow ray flowers and 3-6 yellow disc flowers. The base of the flower is surrounded by 3-4 layers of narrow, hairless, green bracts (phyllaries); the entire set of phyllaries is two to less than three millimeters long. The flower stalks (pedicels) are hairy, about as long as the set of phyllaries, and curve upwards. The fruit is a dry, ribbed seed 1-1.5 mm long with a tuft of white hairs 1.8-2.2 mm long. Canada goldenrod is difficult to differentiate from tall goldenrod (S. altissima) (both are three-nerved), but tall goldenrod has phyllaries longer than 3 mm while Canada goldenrod's phyllaries are always shorter than 3 mm. Some argue the two may be the same species but tall goldenrod blooms later than Canada goldenrod. Of the three very similar species (late goldenrod, tall goldenrod, and Canada goldenrod), only late goldenrod has a hairless stem.

Solidago

Solidago canadensis

Canada goldenrod [Blooms: Jul-Oct]

The tip of broad-leaved goldenrod's stem produces a cylindrical inflorescence (a raceme or a narrow panicle) 1.5-5" long and about a third as wide; smaller racemes (1/2-1.5" long, smaller than the leaves) arise from the axils of the upper leaves. Individual flowerheads are about 1/4" across with 3-4 yellow ray florets asymmetrically deployed around the flowerhead and 4-8 yellow disk florets. The base of the flowerhead is surrounded by 3-5 series of unequal, narrowly oblong, light green phyllaries; the outermost phyllaries are 1-2 mm long while the innermost are 3.7-4.7 mm long. Broad-leaved goldenrod prefers high-quality, moist, shaded woodlands. In Illinois, only broad-leaved goldenrod and woodland goldenrod (Solidago caesia) produce clusters of flowerheads from the axils of the middle and upper leaves. Broad-leaved goldenrod has unusually large flowers for a goldenrod and the ray florets are not evenly distributed around the flowerhead. In addition, woodland goldenrod has smooth or finely serrated leaf margins (rather than coarsely-toothed leaves) and no petioles (the leaves are sessile) — it should be easy to distinguish from broad-leaved goldenrod.

Solidago

Solidago flexicaulis

broad-leaved goldenrod [Blooms: Jul-Sep]

The central stem of late goldenrod gives rise to an inflorescence (a panicle) up to one foot long and wide made up of light green, slightly fuzzy, recurved branches with a few leafy bracts smaller than the stem leaves. Each flowerhead is about 1/4" across with 9-15 yellow ray florets and 7-12 yellow disk florets. Surrounding the base of the flowerhead are 2-5 series of appressed bracts (phyllaries) that combined are 2-4+ mm long; individual bracts are elongate lance-shaped. The flower stalks (pedicels) are minutely hairy, usually shorter than the phyllaries, all attached to one side of the panicle branches and curving upwards. Full-sized late goldenrod plants are imposing — tall, green or reddish-brown, yellow-tipped columns towering over every plant around them. The leaves of late goldenrod are similar to those of Canada goldenrod (S. canadensis), but the latter has hairy stems and tends to be somewhat shorter. Both tall goldenrod (S. altissima) and late goldenrod are three-nerved, have the largest leaves mid-stem, and pyramidal inflorescences, but tall goldenrod has rough-feeling (sandpapery) stems and leaves while late goldenrod has smooth stems and leaves. Of the three very similar species (late goldenrod, tall goldenrod, and Canada goldenrod), only late goldenrod has a hairless stem.

Solidago

Solidago gigantea

tall goldenrod [Blooms: Jul-Sep]

Early goldenrod's inflorescence is apical, a panicle of flowering stems that "often arch upward and outward like a fireworks display" (John Hilty, www.illinoiswildflowers.info). Individual flowerheads are about 1/4" across; they have 4-12 yellow ray florets, not all open at one time, and 8-15 yellow disk florets. The base of the flowerhead is surrounded by 3-4 series of overlapping, narrow, hairless, yellowish-green bracts (phyllaries) that together are 3-4 mm (1/16") long. The pedicels (flower stalks) are usually hairless, all attached on one side of the panicle's flowering branches and curving upward. The fruit is a cone-shaped dry seed 1-1.5 mm long with an attached tuft of light brown hairs 2.5-3.5 mm long. The combination of wing-like leaflets in the leaf axils, hairless stems and leaves, and an inflorescence whose flowering stems flare up and out is diagnostic for early goldenrod. Field goldenrod (Solidago nemoralis) is much the same size and general appearance, but has hairy stems and leaves, unlike early goldenrod.

Solidago

Solidago juncea

early goldenrod [Blooms: Jul/Aug-?]

The wand-shaped, nodding inflorescence of field goldenrod arises from the tip of the stem; it is 3-7" long and widest in the middle, tapering towards either end; the flowerheads are all on one side of the flower branches. Flowerheads are each 1/4" across consisting of 4-10 yellow ray florets and 3-10 yellow disk florets. The bracts (phyllaries) surrounding the base of the flowerhead are in three overlapping series; they are pale greenish yellow, covered in short, white hairs. The fruit is a dry seed 0.5-2 mm long with an attached tuft of light brown hairs. Field goldenrod can be distinguished from other goldenrods by (1) its diminutive size, (2) the inflorescence that nods to one size, (3) leaflets present in leaf axils (4) short, fine hairs on both leaves and stems, and (5) the grayish cast of the leaves.

Solidago

Solidago nemoralis

field goldenrod [Blooms: Aug-Oct]

Upland white goldenrod stems end in a flat-topped panicle 6" across of flowerheads; colonies can present a visually continuous surface of flowers. The flowerheads are 3/4-1" across on 1" stems; each flowerhead has 10-25 white, pistillate ray florets (no stamens) and 30-36 yellowish, perfect disc florets (with both pistils and stamens). The petal-like rays are bright white and spreading, sometimes with notched tips; they look very much like a generic aster flowerhead. The disk florets are dull white and tubular; the five stamens in each disk floret are conjoined and yellow, giving a yellowish cast to the disk. Behind the flowerhead are 4-5 series of hairless bracts (phyllaries), light green at their base, darker green at the tips, each phyllary with a prominent light green mid-vein; the phyllaries are 4 mm long in total. Upland white goldenrod is uncommon in most of northern Illinois except in the sandy soils near Lake Michigan. ITIS and the Flora of North America accept Solidago ptarmicoides as a valid species name; the USDA Plants Database and NatureServe Explorer consider S. ptarmicoides as a junior synonym of Oligoneuron album (as does illinoiswildflowers.info).

Solidago

Solidago ptarmicoides

upland white goldenrod [Blooms: Aug-Sep]

Stiff goldenrod's inflorescence (a corymb) arises from the tip of the main stem and from the upper side stems. It is a compact, flat-topped or rounded mass of flowers 2-5" wide. Each flower is 3/8" across (big for a goldenrod) with 6-13 yellow, pistillate ray florets (with purple styles and no stamens) and up to 35 (usually fewer) yellow, perfect disc florets with five yellow stamens and a purplish, split style. The back of the flowerhead is covered with 3-5 series of overlapping bracts (phyllaries) with the midvein and other veins visible. The fruit is a dry seed that is angular in outline, about 2 mm long with a tuft of white or light brown hairs. The distinctive stiff, rounded upper leaves that clasp the stem are all you need to unequivocally identify stiff goldenrod.

Solidago

Solidago rigida

stiff goldenrod [Blooms: Aug-Oct]

Solidago sempervirens

Solidago

Solidago sempervirens

seaside goldenrod [Blooms: Sep-Oct]

Showy goldenrod's inflorescence is a showy, cylindrical panicle up to 12" long arising from the tip of the stem; the flowering stems are erect or curve upwards and the flowerheads occur on all sides of the flowering stems. (Unlike most goldenrods, where the flowering stems curve outward and downward and the flowerheads are on one side of the flowering stems.) Each flowerhead is about 1/4" across consisting of 4-10 large (for a goldenrod) pistillate ray florets (no stamens) and 6-16 perfect disk florets (both stamens and style). Behind the flowerhead are 3-4 series of overlapping bracts (phyllaries), each with a prominent midvein. The fruit is a 2 mm long seed with dark brown longitudinal grooves and a tuft of light brown hairs. Showy goldenrod is distinguished from other goldenrods by the character combination of: (1) stem leaf margins smooth (not toothed), (2) wing-like leaflets in axils of upper leaves, (3) the stems of the inflorescence erect or curve upward (not out and down), and (4) stems and leaves largely or completely hairless except in the inflorescence.

Solidago

Solidago speciosa

showy goldenrod [Blooms: Jul-Oct]

Elmleaf goldenrod's stem (and sometimes upper leaf axils) produces an open, airy inflorescence (a panicle) at its tip that may be a foot tall and wide with arching, widely-spreading branches. The flowerheads rest on very short stems (nearly sessile) along one side of the major branches, facing upward; on the opposite side of the branches are small (1") bracts. Both stems and branches in the inflorescence are covered with hairs. The flowerheads are 1/8-1/4" across with 3-6 yellow, pistillate ray florets (no stamens) and 4-7 yellow, perfect disk florets (both stamens and a style). Surrounding the base of the flowerheads are 16-18 bracts (phyllaries) in 2-3 overlapping series.

Solidago

Solidago ulmifolia

elmleaf goldenrod [Blooms: Jul-Oct]

Perennial sowthistle's upper stems produce long flower stalks at their tips. Individual flowerheads are 1-2" in diameter, composed entirely of 80-250 yellow ray florets; disc florets are absent. The fruit, popular with goldfinches, is a flat, dark brown seed with tapered ends, several longitudinal ribs, and a tuft of fine white hairs (like a dandelion). Glandular hairs are typically present on the flower bracts and stalks; if these glandular hairs are absent, glands are present in the epidermis. Perennial sowthistle is indeed a perennial, one with a taproot that may penetrate as deep as 9' into the soil. Of the local sowthistles, perennial sowthistle has by far the largest flowers; other species never exceed 3/4".

Sonchus

Sonchus arvensis

perennial sowthistle [Blooms: Jun-Oct]

Prickly sowthistle's flowerheads are dandelion-like, less than 3/4" in diameter and composed entirely of 80-250 ray florets. Glandular hairs are present on both the flowerhead bracts and on the stalks just below the flowerheads. The fruits are flattened, brown, 2-3 mm long oval seeds with 3-4 ribs per side and a tuft of white hairs on one end. Prickly sowthistle has shiny green (as opposed to the dull green of the other two species) leaves with rounded lobes (as opposed to pointed lobes of common sowthistle) at the base of the leaves. Perennial sowthistle (Sonchus arvensis) has larger (1-2" as opposed to <3/4") flowers and small, rounded lobes at the base of the leaves. The triangular lobes on the base of the leaves of common sowthistle (Sonchus oleraceus) are not found in the other two species.

Sonchus

Sonchus asper

prickly sowthistle [Blooms: Jun-Oct]

Common sowthistle flowerheads are less than 3/4" in diameter and look very dandelion-like; they open in the morning and close by noon. Each flowerhead consists of numerous (80-250) yellow ray florets; disc florets are absent.

Sonchus

Sonchus oleraceus

prickly sowthistle [Blooms: Jun-Oct]

The central stem of giant bur-reed produces an inflorescence at its tip with 1-6 female flowers in the lower parts of each branch of the inflorescence and up to 20 male flowers in the upper parts. (Male and female flowers are separate and distinct.) Male (staminate) flowerheads look like a fireworks-burst of white filaments and yellow-brown anthers; individual florets are densely packed, each with five stamens with white filaments and a yellow to brown anther. The female flowerheads are greenish and "prickly" with prominent green cones (the female florets) covering the surface; each pistillate floret has a basal green ovary covered with scale-like tepals with dark tips and an apical white style bearing two white stigmas. Giant bur-reed is wind pollinated. In fruiting flowerheads, the stigmas turn dark and wither but do not drop off; the florets elongate and widen, turning brown as the fruits on the seedhead ripen. The fruit is a brown seed 5-10 mm long and nearly as wide, shaped like an inverted pyramid that abruptly narrows to a 2-4 mm long apical beak (the style remnant). Giant bur-reed is superficially sedge-like but instead is more closely related to cattails. Giant bur-reed prefers wet conditions (up to a foot of water) with minimal waves and gentle currents.

Symphytum

Sparganium eurycarpum

giant bur-reed [Blooms: May-Jul]

Saltmarsh sand-spurry flowers consist of five elliptical green sepals, five white to pink petals slightly longer than the sepals, 2-5 stamens with bright yellow anthers, and three short (0.7 mm), thread-like styles and three stigmas. In the Great Lakes region, saltmarsh sand-spurry is widely present along roads where salt is used as a deicer. Some sources refer to this plant as Spergularia marina, but ITIS rejects that binomial; Spergularia salina is the accepted name.

Spergularia

Spergularia salina

saltmarsh sand-spurry [Blooms: May-Aug]

White meadowsweet's branches end in 2-6" long, oblong or pyramidal (1-4 times longer than wide) panicles of densely packed flowers that open from the top down. The flowers are about 1/4" across and are very similar to Eastern Meadowsweet (Spiraea latifolia) except for color (white rather than pink, although often pink as buds). Individual flowers consist of five triangular, light-green sepals; five white petals narrowest at their base, longer than the sepals; numerous (15-50) long, white stamens with white or pink anthers; and five light green or white pistils. The long stamens on the flowers give the flowerhead a fuzzy outline. The fruit is a cluster of 4-6 follicles, each containing one seed. When ripe, the top of the follicle splits, allowing the seed to fall out when the stem is shaken. Surrounding the pistils is a ring of pink, orange, or yellow tissue that marks the location of the nectaries. White meadowsweet prefers wet areas along the lagoons in Jackson Park.

Spiraea

Spiraea alba

white meadowsweet [Blooms: Jul-Sep]

Great Plains ladies'-tresses flowers are arranged in three rows spiraling up around the stem. The petals and sepals are both white with a tinge of yellow on the lower lip (lower petal). The two petals are top and bottom of the bloom, with the lower, ruffled petal extending out and down; the two sepals are narrower than the petals and flank the side of the bloom, sometimes arching higher than the petals. Typically, there is a single stamen; the style is fused to the surface of the lower petal deep in the flower. The base of the flower is nestled between oval green bracts which cup the ovary and taper to a sharp point above the flower. Great Plains ladies'-tresses are probably pollinated by bumblebees, but information is sparse. If you get down on your hands and knees (or, better, lie down beside the plant) and put your nose up against the blooms, it is really true that they smell like vanilla(!). A closely related species, nodding ladies'-tresses (Spiranthes cernua) was once considered to be the same species as Great Plains ladies tresses, but the former still has its basal leaves on blooming and no scent while the latter never has the basal leaves when blooming and the flowers smell like vanilla.

Spiranthes

Spiranthes magnicamporum

Great Plains ladies'-tresses [Blooms: Sep]