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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]

Lance-leafed coreopsis flowerheads are 2-3" across; they have about eight broad, yellow ray florets with 3-5 (usually four) bold, sawtooth lobes at their tips (that may also be subdivided); the numerous disk florets are also yellow, tubular, about 1/4" long with 4-5 tiny lobes. The seeds are black, egg-shaped, and 2.5-5 mm long with thin papery wings along the edges.

Coreopsis

Coreopsis lanceolata

lance-leafed coreopsis [Blooms: May-Jun]

Prairie coreopsis flowerheads occur alone or in pairs on 1/2-2" long peduncles attached to the ends of stems. Each flowerhead is about 2" across with 8-12 ray florets; two prominent longitudinal veins divide each ray floret petal into thirds. The disc florets are tubular with 4-5 lobes; they are initially yellow, but turn brownish with age.

Coreopsis

Coreopsis palmata

prairie coreopsis [Blooms: Jun-Jul]

Plains coreopsis flowers are 1-2" across, with 6-12 (usually 8) ray florets, each with three lobes at their tips (center largest). The ray florets are sterile, typically yellow at their tips, transitioning abruptly to a maroon color more basally. The disk florets are perfect (have both anthers and pistils), reddish-brown to maroon with the florets at the edge of the disc with bright yellow highlights (either the anthers on the fused stamens or the split stigma of the pistils); individual florets have four teeth/lobes. The involucre of the flowerhead is often reddish-tinged, particularly obvious when cupping the developing seedhead.

Coreopsis

Coreopsis tinctoria

plains coreopsis [Blooms: Jun-Oct]

Tall coreopsis flowerheads arise from peduncles up to 10" long; the flowerheads are 1.5-2" across with eight sterile, yellow ray florets (each with two deep folds that divide the ray florets longitudinally into thirds) and numerous reddish-purple, fertile disk florets. The corollas of the disc florets are tubular, with 4-5 triangular lobes at their tips, and about 5 mm (~1/4") long; each has five stamens (fused together at their tips) with yellow anthers, and a single bifurcated style with pointed tips.

Coreopsis

Coreopsis tripteris

tall coreopsis [Blooms: Aug-Sep]

Whorled coreopsis' flowerheads are a bright golden yellow, 1-2" across, with eight yellow, elongate egg-shaped ray flowers and numerous (30-40) yellow disk flowers.

Coreopsis

Coreopsis verticillata

whorled coreopsis [Blooms: Jun-Sep]

Cornelian cherry dogwood is a European exotic that has been planted in Jackson Park. Flowers appear in umbels before the leaves emerge. The flowers are small (1/8"), with four bright yellow, lance-shaped petals, four stamens, and a cone-shaped, hairy receptacle; the single pistil emerges from the center of the ovaries. The fruit is an oblong, dark red drupe about an inch long.

Cornus

Cornus mas

Cornelian cherry dogwood [Blooms: Apr-?]

Narrow-leaf hawksbeard is a weedy-looking plant that reaches a size of 8-40". Flowers occur in a panicle (usually arising from a leaf axil) with up to 20 dandelion-like flowerheads. Individual flowerheads are about 1" across with 30-70 yellow ray florets (the "petals"); beneath the ray florets are two layers of green bracts — an inner layer of 12-15 3/8" long, sharply-pointed, keeled bracts covered in wooly or short stiff hairs and an outer layer of bracts half the length of the inner layer, sometimes ridged, with hairs like the inner layer. Narrow-leaf hawksbeard can be distinguished from similar dandelion-like flowers (Crepis pulchera, Crepis capillaris, and various sowthistles and hawksweeds) by the presence of auricles on the stem leaves and a layer of appressed hairs on the inside surface of the inner bracts, best seen with a magnifier.

Crepis

Crepis tectorum

narrow-leaf hawksbeard [Blooms: May-?]

Shrubby cinquefoil flowers are 3/4-1.5" across, bright yellow, with petals that are circular and overlap, 15-20 stamens with golden anthers, and numerous pistils clumped in the center. The five sepals are largely hidden behind the petals; only the sepal's tips protrude.

Dasiphora

Dasiphora fruticosa

shrubby cinquefoil [Blooms: May-Jul]

Annual wallrocket flowers occur on the tips of the stems. Each flower has four bright-yellow, oblong petals about 1/4" long with rounded tips; five light-green stamens with yellow anthers; and a green, stout pistil with an expanded, rough-textured stigma. The fruits are elongate (3/4-1"), narrow (1.5-2.5 mm), cylindrical siliques.

Diplotaxis

Diplotaxis muralis

annual wallrocket [Blooms: May-Oct]

Mock strawberry (aka, Indian strawberry) flowers are borne on a single flower stalk. Flowers are 1/2-3/4" across with five sharply-pointed, triangular green sepals as long as the petals and covered with long hairs on their outer surfaces; five bright-yellow petals wider at the tip than the base; 15-25 stamens with bright yellow anthers; and a central yellow receptacle with numerous pistils covering its surface. Just below the sepals are five small bracts (leaves), each with three pointed lobes at its tip; these persist and are present below the sepals on the fruit. The fruit is a bright-red expanded receptacle ~1/2" in diameter, globose or ovoid, that is nestled in the sepals; bright red seeds project from the fruit's surface like pointed bumps. The fruit is edible but tasteless. The word "Indian" in the common name refers to the country "India" rather than Native Americans; "Indian" strawberry was introduced from Asia. The five small bracts (leaves) just below the sepals in mock strawberry, each with three pointed lobes at its tip, are present in both the flowers and the berries and are a diagnostic character of mock strawberry.

Duchesnea

Duchesnea indica

mock strawberry [Blooms: Apr-Sep]

In Robin's plantain the basal leaves, stem leaves, stems, and flower stalks are all very hairy. Flowerheads arise from the tips of the stems as a group of 1-6. Individual flowerheads are 1-1.5" across; the numerous (50-100) ray florets bear long white (sometimes light pink or violet) petals surrounding a flat, yellow-orange disc of disc florets ~1/2" across. The base of the flower is surrounded with 2-3 layers of light green phyllaries (often with brown or purple tips) which taper smoothy into the stalk.

Erigeron

Erigeron pulchellus

Robin's plantain [Blooms: Apr-May]

Wormseed mustard stems are medium green, angular or grooved, covered relatively sparsely with tiny appressed hairs. At the tip of the stem is a raceme of yellow flowers, each 1/4-1" long and 1/4" across; more peripheral flowers in the raceme bloom first. Each flower has four pale green sepals 2-3 mm long, four yellow petals 3-5.5mm long, six stamens with yellow anthers (two stamens shorter than the other four), and a single style. The basal rosette withers about the time the seeds begin to form, while flowers are still present. Seedpods are four-angled siliques that grow directly from the center of the flowers. Wormseed mustard prefers open, disturbed habitats.

Erysimum

Erysimum cheiranthoides

wormseed mustard [Blooms: Apr-?]

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]

European spindletree flowers (usually less than 7) occur in clusters (cymes) with long peduncles; they have four sepals, four petals, four stamens with white anthers, and a single stout style. The greenish-white or yellow petals on the flowers appear to be very narrow, half the width of the petals of Hamilton's spindletree. (In reality, the petals are curled into a U-shape towards the stem so they only appear narrow.) The sepals are pale green, about half the length of the petals, and bent back beneath the flower. The fruit is pink, not red; the arils covering the seeds are orange, not red or scarlet. European spindletree blooms later in the spring in Jackson Park than Hamilton's spindletree.

Euonymus

Euonymus europaeus

European spindletree [Blooms: Apr-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]

Lance-leafed goldenrod is only distantly related to the other goldenrods (all genus Solidago) found in Jackson Park. The inflorescence is a flat-topped or slightly domed panicle. Flowerheads are cylindrical, minute (1/8" across, the smallest of the goldenrods), with 15-25 ray florets with minute petals and 5-10 disc florets. The outermost bracts around the base of the flower are green-tipped. Flowers across the inflorescence bloom at different times so the inflorescence often looks a bit shopworn. Lance-leafed goldenrod refers wet, soggy habitats.

Euthamia

Euthamia graminifolia

lance-leafed goldenrod [Blooms: Jul-Sep]

Indian blanket flowers are 1-2.5" across with 6-15 sterile ray florets; the petals are 3/4-1.25" long, red or brownish-red with yellow tips; the base of the petal is narrow and the tips of the petals are divided into three sharp or rounded teeth or lobes. Disc florets are brown, numerous (40-100+), with tubular corollas that may be orangish, red, brownish-red, or purple with five tringular, hairy lobes at the apex; the flowers are perfect with both stamens and styles.

Gaillardia

Gaillardia pulchella

Indian blanket [Blooms: Jul-Oct]