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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]

Bladdernut produces white, drooping, bell-shaped flowers in clusters of 5-12 from the axils of the leaves. Each flower is pendant on a long stalk, bell-shaped, about 8 mm long and about 6 mm wide. Flowers have five greenish-white sepals overlapping much of the petals, five bright white petals (visible through the gaps between the sepals) that flare at their tips, five stamens with white filaments and deep yellow-orange anthers, and a greenish-white style with a three-lobed stigma extending beyond the mouth of the bell. The flower stalks (pedicels) are about 1.5-2 times the length of the flower. The fruit is a greenish-white to brown, papery pod (like a "Chinese lantern") that is about 3" long and 2" across with three lobes/chambers, pointed on their distal ends; each chamber contains up to four 1/4" seeds. Both flowers and fruits are distinctive and easily recognizable.

Staphylea

Staphylea trifolia

bladdernut [Blooms: Apr-May]

Common chickweed's flower stems arise from the axils of outer pairs of leaves; the flower stems terminate in small cymes of flowers. Individual flowers are about 1/4" across, consisting of five green sepals longer than the petals, tapering to a point, hairy on the outside; five white, widely-spaced, bifid (deeply notched, each appearing double) petals; 2-10 (usually 3-5) stamens with reddish-violet anthers; and a central green ovary with three styles fused except at their flaring tips. The fruits are light brown, cylindrical, 4-6 mm long seed capsules nestled in the embrace of the (hairy) sepals with six small teeth around their upper ends. Common chickweed is usually self-pollinating (autogamous) but is occasionally cross-pollinated by flies. Chickweeds of the genus Stellaria (like common chickweed) have three styles; chickweeds of the genus Cerastium (like mouse-eared chickweed) have five styles. The flowers of whitlow-grass (Draba verna) are superficially similar to common chickweed in size and color but have only four bifid petals rather than five. One odd (but distinguishing) characteristic of common chickweed — if you bend the stem back and forth, the epidermis and parenchyma will split, leaving a central vascular bundle which will stretch elastically if you then pull the broken segments apart.

Stellaria

Stellaria media

common chickweed [Blooms: Apr-May]

Trailing wild-bean is a native annual, a sprawling or climbing vine 3-9 feet long found in sandy habitats. The stems are slender, round in section, range from light green to dull reddish, and are quite hairy; they produce occasional branches and can twine around neighboring plants. Leaves are alternate, trifoliate compound, with broadly oval to teardrop shaped leaflets 1-2" long and 1/2-1.25" across, widest at the base with a pointed tip. The terminal leaflet may be slightly larger and has a short stalk (petiolule); the lateral leaflets are sessile. Sometimes the bases of the leaflets have a shallow lobe on each side of the midline. The compound leaf has a 1-2" long, slightly fuzzy petiole. Some leaf axils produce 3-6" long flower stalks (peduncles) with 3-10 nearly stalkless flower buds at the tip, only a few of which are open at any one time. The flowers are 1/3-1/2" across, light pink to creamy pink, pea-like with five petals, but the keel is sharply curled upward such that it almost touches the banner (the vertical petal). The fruit is a bean-like seedpod, 2-3.5" long, sparsely covered with short hairs, initially green but turning dark brown as it matures; the seeds are oblong, black, and are also covered with short hairs.

Strophostyles

Strophostyles helvola

trailing wild-bean [Blooms: Aug-Sep]

Elongated racemes or short clusters arise from snowberry's leaf axils or the tips of shoots. Each flower is about 8 mm long and 6 mm across with a dull green, hairless, tubular calyx, swollen near the base, with five shallow teeth; a bell-shaped, light pink or whitish pink corolla with five triangular lobes; five short stamens attached to the petals with tan anthers at the tip of the filament; and a light green ovary with a single style. Neither stamens nor style extend past the margin of the corolla. Long white hairs crisscross the open space inside the corolla. The fruit is a drupe (a stone fruit, like a cherry) 8-16 mm in diameter, bright white, and more or less spherical at maturity with a pair of nutlets inside.

Symphoricarpos

Symphoricarpos albus

snowberry [Blooms: Jul-Sep]

Some of coralberry's leaf axils produce dense cluster of greenish, sessile flowers. Individual flowers are 1/4" long consisting of a short green calyx with five teeth and slightly swollen basally; a stubby, tubular corolla with five bluntly-rounded lobes; five stamens with white anthers; and a pale green ovary with a hairy style. The anthers barely extend to the edge of the corolla lobes; the stigma is inset slightly deeper. The fruit is a single globoid berry containing two seeds, 1/4" long and reddish-purple when mature.

Symphoricarpos

Symphoricarpos orbiculatus

coralberry [Blooms: Aug-?]

The leafy stems of Drummond's aster end in a panicle 1/2-2 feet long and half as wide bearing white flowerheads with yellow or maroon centers. Individual flowerheads are 1/2-3/4" across; they have 10-15 ray florets and 13-15 disk florets. The ray florets have bright blue, purple, or white tubular corollas and white rays (petals); the disk florets have cream to yellow tubular corollas, turning deep purple or reddish purple with age. Both disk florets and ray florets are perfect with bright yellow anthers on the stamens and white, bifurcated styles, but the ray florets are sterile. The base of the flowerhead is covered with 4-5 series of overlapping, light green phyllaries (bracts). Each phyllary is 4-6 mm long, light green, with a diamond-shaped patch of dark green near their tip. The fruit is a dry seed with a tuft of attached brown to white hairs. Note that the leaf petioles are winged and the leaves are broad and toothed. The upper surface of the leaf is rough (unlike Short's aster, the most common species in Jackson Park that you might confuse with Drummond's aster). The even pubescence (down-like hairs) on the underside of the leaves and along the stems distinguishes Drummonds aster from the other look-alike aster in Jackson Park, white arrowleaf aster (Symphyotrichum urophyllum). The phyllary pigmentation is also distinctive.

Symphyotrichum

Symphyotrichum drummondii

Drummond's aster [Blooms: Sep – ?]

Each heath aster flowerhead is 1/3-1/2" across with 8-20 ray florets (usually 12) and 6-12 disk florets. The ray florets are sterile; the disk florets are perfect and fertile. The phyllaries occur in 3-4 series on the back of the flowerhead; they are blunt-tipped, often recurved away from the flowerhead, with a distinct apical spine. Also note the spines at the tips of the numerous needle-like bracts on the flower stems. (Note: hairy aster (S. pilosum) also has such apical spines but has larger flowers, rolled, needle-like phyllaries with a smaller spine, and spreading hairs on the stems.)

Symphyotrichum

Symphyotrichum ericoides

heath aster [Blooms: Sep – Nov]

Smooth blue aster's central stem produces a one-half to one foot long (and half as wide) panicle of flowerheads with stiff, ascending branches covered with small, leafy bracts. Smaller panicles may arise from some lateral upper stems and the axils of the upper leaves. Individual flowerheads are 0.5-1" wide, consisting of 15-30 light lavender or light blue-violet ray florets and 19-33 disk florets that are initially a whitish yellow but change to purplish red over time. The phyllaries that cover the back of the flowerhead are arranged in 4-6 overlapping series and have a diamond-shaped, green tip, often with a spot of red at the very tip. The fruit is a brown, dry seed, flattened, narrowly cone-shaped with 4-5 longitudinal ribs, 2-4 mm long with a tuft of brown hair. The most useful character to distinguish smooth blue aster from other asters is the lack of hairs on its stems and leaves; the uniformly clasping leaves (no petioles) is another useful character. For example, the superficially similar skyblue aster (Symphyotrichum oolentangiense) has lower and middle leaves with distinct petioles and none of its leaves actually clasp the stem.

Symphyotrichum

Symphyotrichum laeve

smooth blue aster [Blooms: Aug – Sep]

Panicled aster's central stem gives rise to an 8" long panicle (4" wide) of flowerheads; panicles may also arise form lateral stems and the axils of upper leaves. The panicle branches tend to be hairier and more often grooved than the stems; there are bracts (1.5" long, 8 mm wide) at the base of the panicle branches and the base of the flowerhead stalks. Individual flowerheads are 1/2-3/4" across with 1.5" long flower stalks (peduncles). Flowerheads have 20-40 white (less often blue or violet), pistillate (no stamens) ray florets, and an equal number of perfect (pistils and stamens) disc florets that are initially yellow, turning red orange with age. Phyllaries (bracts) cover the back of the flowerhead in 3-6 overlapping layers; the phyllaries are narrow, green with paler bases, appressed or slightly spreading, with the outer layer shorter than the inner. The fruit is a 1.5-2 mm long gray seed with a tuft of dull white or yellowish hairs. It's easy to confuse panicled aster with other asters that have small, white flowerheads. Look for: (1) leaves with wedge-shaped (not rounded or heart-shaped) bases, (2) mature leaves hairless on both sides, (3) stems with lines of white hairs, and (4) flowerheads with at least 20 ray florets. (Count the "petals.")

Symphyotrichum

Symphyotrichum lanceolatum

panicled aster [Blooms: Aug – Oct]

Panicles of flowerheads up to 10" long and 6" across arise from the upper stems (and some side stems) of calico asters. Individual flowerheads are about 1/3" (8 mm) across, typically consisting of 8-15 white ray florets and 8-16 cream or light-yellow disc florets turning brown or reddish purple with age. The flowerheads sit on a 1/3" long, hairy flower stalk (peduncle) with a few leaf-like bracts along the peduncle. The base of the flowerhead is covered by phyllaries (bracts) in 3-4 overlapping layers; the phyllaries are sparsely hairy, appressed or slightly spreading, with a darker green lance- or diamond-shaped tip. The fruits are fuzzy dry seeds with a tuft of white hairs. Calico asters are distinguished from other small, white asters by: (1) very small flowerhead (<1/2"), (2) relatively few (9-16) ray florets/petals, (3) creamy white or pale (not bright) yellow disk florets, (4) lance-elliptic leaves with hairs only on the midvein, (5) stems with lines of soft, white hairs. Other asters (e.g., panicled aster) will have one or more of these characters, but not the full suite.

Symphyotrichum

Symphyotrichum lateriflorum

calico aster [Blooms: Sep – ?]

Clusters of flowerheads occur at the tips of the upper stems of New England asters. Individual flowerheads are large (1.5" across) with 50-75 (!) purple, lavender, or pink ray florets; the 50-110 disk florets are yellow or gold, turning reddish purple with age. A healthy New England aster with two or three dozen flowerheads is an impressive sight indeed. Phyllaries surround the back of the flowerhead in 3-5 layers. They are green or purple-tinged, very narrow but robust, widely spreading or reflexed, with the outermost layer of phyllaries covered with short glandular hairs. The fruit is a longitudinally ribbed, quite hairy, dry seed with a tuft of long, light brown hairs. The large, showy flowerheads with very large numbers of ray florets (petals) can't be confused with any other aster in Jackson Park.

Symphyotrichum

Symphyotrichum novae-angliae

New England aster [Blooms: Aug – Nov]

Skyblue aster's central stem terminates in a 6-18" long panicle of flowerheads; the panicle is twice as long as wide. The panicle has a central stalk (rachis), several primary branches and numerous secondary (off the primary) and tertiary (off the secondary) branches that end in flowerheads. The branches have scale-like, 3/4" long leafy bracts spaced along their lengths. Individual flowerheads are 1/2-3/4" across with 10-25 lavender or pale blue ray florets and 20-25 disk florets. The disk florets are initially yellow, turning reddish-purple with age; they seem to me to be unusually large for an aster. The phyllaries (bracts) surrounding the base of the flowerhead are small (2 mm) and tightly appressed, each with a diamond-shaped green tip and often with a spot of blue-purple at the very tip. The fruits are bullet-shaped, 1.5-2mm long dry seeds, purplish brown, with a tuft of hairs. Skyblue aster is similar to smooth blue aster (S. laeve), but that species has sessile leaves; sky blue aster has petioles on the lower and middle leaves, only the upper leaves are sessile. Skyblue aster is also similar to Short's aster (Symphyotrichum shortii), but the latter has upper leaves with a heart-shaped base rather than smoothly tapering to a sessile attachment as in skyblue aster. Generally, skyblue aster is most easily identified by the long, narrow, arrowhead-shaped lower leaves that feel like fine sandpaper on both surfaces.

Symphyotrichum

Symphyotrichum oolentangiense

skyblue aster [Blooms: Sep – Oct]