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Common cinquefoil is a sprawling plant less than a foot tall that produces numerous prostrate stolons up to 3' long. Both the stems and the stolons are initially green but become more reddish. The leaves are alternate and palmately compound with five leaflets, each with serrated margins; the leaflets are three to four times longer than wide. The sparse flowers develop singly on long pedicels that arise from the axil of some compound leaves. They are bright yellow and 1/2" across with triangular sepals shorter than petals; the petals are narrowest at their base and usually rounded at their distal edge. About 20 stamens with yellow anthers (turning reddish with age) surrounded a central mass of styles. Common cinquefoil has flowers and leaves that are superficially similar to those of mock strawberry (Duchesnea indica). However, the leaves of common cinquefoil have extremely sharp-edged, well-defined teeth on the leaf margins (strongly resembling the edge of a hand saw), not the bluntly-tipped teeth of mock strawberry. 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 berries are diagnostic of mock strawberry; they are absent in common cinquefoil. Note that rough cinquefoil’s leaves have three leaflets, common cinquefoil's leaves have five, and prairie cinquefoil's leaves have 7-11 leaflets.

Potentilla

Potentilla simplex

common cinquefoil [Blooms: May-Jul]

Shooting star's smooth, leafless flower stalk is reddish-green, bearing 6-20 (sometimes up to 40) nodding flowers at its apex that are suspended from delicate pedicels. Each flower has a green calyx with five short, triangular green lobes, five white or pale lavender petals reflexed backwards (upwards) and often twisted along their lengths. A "reproductive cone" (five yellow to purple stamens tightly appressed around a single, purplish-green central style) extends down from the yellow petal bases. The fruit is a short, ovoid seed pod, initially green, turning reddish-brown with maturity, 1/4-3/4" long with a pointed tip that is oriented vertically (the curvature of the pedicel reverses after fertilization); it is filled with small, dark seeds. The flowers of shooting star are superficially similar to those of horse nettle (Solanum carolinense) but the latter do not hang from a long stalk like shooting star (and have lots of prickles and spines that shooting star lacks). The convergent evolution of "reproductive cones" in both shooting star and horse nettle is an adaption to increase the efficiency of buzz pollination by large bees, especially bumblebees. The older name for this species ("Dodecatheon meadia") is no longer considered valid.

Primula

Primula meadia

shooting star [Blooms: Apr-May]

American plum flowers first appear before or at leaf emergence; they occur in roughly spherical clusters (umbels) of two to five flowers, arising from leaf axils. Each flower is ~1" across, held away from the twig at the base of the umbel on 1/2-1" petioles; there are five egg-shaped petals with narrow bases, white with a touch of pink, five narrow, somewhat fleshy, green sepals much shorter than the petals, a single style, and numerous (10-30) stamens with tan anthers. The fruits are about 1" across, initially green but turning reddish-purple with the waxy bloom typical of plums when ripe; inside is a single seed (a "stone," like a peach). Because this tree usually flowers when the leaves are only beginning to open, it produces an especially showy display. It is widespread across Jackson Park.

Prunus

Prunus americana

American plum [Blooms: Apr-May]

European bird cherry It has showy white flowers (so is widely planted as an ornamental) and reaches heights of 30-40'. Blooms are produced in elongate, cylindrical racemes of 15-50 flowers at the tips of twigs, similar to but shorter than those of chokecherry (Prunus virginia). Individual flowers consist of five green, broadly-spreading or reflexed sepals (longer than wide); five white or cream colored petals that are 1/4-3/8" long, oval but widest in the center; 10-30 stamens half the length of the petals around a cup-shaped, often green hypanthium (hairless externally); and a single central pistil. The fruit is a small, black drupe (cherry) with an extremely bitter taste to mammals, but it is much loved by birds, who disperse the pits. European bird cherry is very similar to another species present in Jackson Park, chokecherry. European bird cherry tends to be more tree-like in habit than chokecherry and tends to have shorter stamens (half the length of the petals) than chokecherry (as long as the petals). It's not clear how much of this expansion is due to Park District policy and how much is due to natural seed dispersal.

Prunus

Prunus padus

European bird cherry [Blooms: Apr-May]

Peach flowers arise along young branches, blooming beginning before the leaves have opened in the spring; the flowers are usually solitary but occasionally occur in pairs. Individual flowers are 1-1.5" long consisting of a burgundy-colored calyx with five rounded apical lobes (sepals); five spreading pink (rarely, white) petals, oval with abruptly narrowed bases ("clawed"); 15-30 stamens with pink filaments and yellow to orange anthers; and a pistil with a single light green style nearly as long as the stamens. Fertilized flowers are replaced by green, fuzzy ovoids, eventually up to 3" long and across and containing a single seed; peach-colored when mature.

Prunus

Prunus persica

peach [Blooms: Apr-May]

Sand cherry is a 4-8' tall shrub; the Great Lakes variant of this species (Prunus pumila spp. pumila) is restricted to the states (and the Canadian province) that touch on the Great Lakes. Blooms occur in umbels of 1-3 flowers; flowers open before the leaves but may persist after some leaves have emerged. Individual flowers are about 1/2" across, consisting of five sepals with rounded tips that are about a third the length of the petals; five white, round- or egg-shaped petals; 10-30 white stamens with yellow anthers emerging from a reddish, cup-shaped hypanthium; and a single, central style. The fruit is a reddish-purple to black, shiny cherry (drupe) about 1/2" in diameter. Sand cherry is found along the shores of the Great Lakes on beaches (sandy, gravelly, or rocky), dunes, and the swales between dunes.

Prunus

Prunus pumila

sand cherry [Blooms: Apr-May]

Black cherry (Prunus serotina) is a is a deciduous tree that can grow up to 80' tall. It typically has a single central trunk below and leafy crown that is taller than wide. Flowers occur in racemes 4-6" long with 20-60 1/2" wide flowers packed around the elongated inflorescence. Individual flowers consist of five green, triangular sepals, five white petals broader at their distal tips and at least three times longer than the sepals, 10-30 stamens with yellow anthers around a reddish-orange hypanthium, and a single, central pistil with a flattened stigma. After fertilization, each flower produces a globoid, fleshy drupe about 1/4" across. The immature cherries are green; as they mature the fruit turns first dark red, they purple-black at maturity. These fruits are sweet but slightly bitter; the black cherry you buy in the grocery store is larger (at least 1/2" across), sweeter, and a species native to Eurasia (Prunus avium).

Prunus

Prunus serotina

black cherry [Blooms: May-June]

Japanese flowering cherry is an exotic from East Asia widely grown in North America as an ornamental (for its showy spring flowers). The flowers occur is small clusters of 2-5 white, pale pink, or deeper pink flowers that (unlike most cherries) dangle face-down beneath the stems from short spurs. The fruit consists of small, round drupes that turn black when mature. Leaves, stems, and fruit, and seeds are toxic to mammals. Many of the cultivars of Japanese flowering cherry are highly hybridized and nearly unrecognizable as being derived from Prunus serrulata.

Prunus

Prunus serrulata

Japanese cherry [Blooms: Apr-May]

Chokecherry is a shrub or small tree 8-25' tall. Flowers occur in spectacular racemes ~6" long with 15-20 white, 1/2" wide, bowl-shaped flowers with an orange-yellow center (hypanthium); the flowers are attached to a central, greenish-yellow stalk. Individual flowers consist of five sepals (initially green, later turning yellow) shorter than the petals, five white petals that narrow sharply near their bases, 15-20 stamens about as long as the petals, and a pistil with a single style. Crushed leaves smell strongly of bitter almonds. Fruit is a red to black globular drupe <1/2" wide that contains a single hard-coated seed (stone) and has a VERY bitter taste; the seed contains high levels of hydrogen cyanide. The fruit is eaten by a wide variety of mammals and birds; the flesh of the fruit traditionally was one of the components of pemmican in indigenous cultures. (The hydrogen cyanide is not a danger unless the hard shell of the seed is broken open.) Chokecherry is similar to wild black cherry (Prunus serotina), but P. serotina has incurved teeth on its leaf margins. Chokecherry is very similar to an exotic also present in Jackson Park, European bird cherry (Prunus padus). European bird cherry tends to be more tree-like in habit than chokecherry and tends to have shorter stamens (half the length of the petals) than chokecherry (as long as the petals). Chokecherry in Jackson Park is often infested with black knot fungus (Dibotryon morbosum).

Prunus

Prunus virginiana

chokecherry [Blooms: Apr-May]

Hoptree (a.k.a., wafer ash) is a large shrub with a rounded, irregular crown and (usually) a robust central trunk up to 6" across. Hoptree may produce single-sex (male or female) or bisexual (male and female organs both present) flowers on the same tree. Individual flowers are about 1/4" across, regardless of gender. Perfect (bisexual) flowers have 4-5 greenish sepals, 4-5 narrow, creamy white petals, 4-5 stamens with hairy white bases and yellow anthers, and a single, flattened green pistil. Male flowers are more or less identical but lack the pistil; female flowers are more or less identical but lack the stamens. The fruits are single seeds 1-1.5" long with a broad, flattened, papery wing extending almost all the way around the seed.

Ptelea

Ptelea trifoliata

hoptree [Blooms: May-Jun]

triped squill is another early spring wildflower native to western Asia and the Caucasus; it tends to grow in clumps of plants 4-6" across. There are (only) two dark green, basal, hairless leaves up to 6" long and ~1/2" wide that widen towards their tips; the margins are smooth. A cluster (raceme) of 3-6 flowers are present on a stalk ("scape") 4-8" tall; overall, the cluster and scape resemble the related wild hyacinths. Each flower has six white tepals with a medial blue stripe. The filaments of the six stamens are flattened and fused together to form a white central, lobed, hollow cone that surrounds the style; the anthers are yellow and lie just inside the tip of the cone. This plant is one of the earliest to bloom in the spring in Jackson Park, but goes dormant in the late spring, basically biding its time until the next year. It prefers moist, well-drained soils.

Puschkinia

Puschkinia scilloides

striped squill [Blooms: Mar-Apr]

Small-flowered buttercup is a native species that has flowers similar to several other buttercups but is distinguished by its broad range of leaf shapes — other buttercups don't have this wide a variety of leaf shapes on a single plant. The flowers are stalked in groups of one to three on the end of the stems. Each flower is 1/4" across with five lance-shaped or triangular petals that are shorter than the sepals. There are five broadly rounded sepals, a ring of 5-10+ stamens with yellow anthers, and a central mound of green carpels, each with a pistil. After fertilization, the carpels enlarge and the central mound elongates until it is ovoid; the fruits (achenes) are shiny and have small beaks.

Ranunculus

Ranunculus abortivus

small-flowered buttercup [Blooms: Apr-May]

Lesser celadine flowers arise singly from the axils of the upper leaves or on the ends of stems. Individual flowers are about 1" across with three light green sepals half the length of the petals, 7-12 yellow, oblong petals, and a ring of about 30 (yellow) stamens around a central group of about 15-20 (greenish) pistils. This species rarely produces fruit, instead reproducing asexually. The alternative name "Ficaria verna" is occasionally used for lesser celadine, but that name is now considered invalid.

Ranunculus

Ranunculus ficaria

lesser celadine [Blooms: Apr-May]

Hispid buttercup is a native species that gets up to about a foot tall; plants tend to become more sprawling as they grow. Flowers are 3/4-1" across, arising from the leaf axils on stalks with short, appressed hairs. Each flower has five light green sepals shorter than the petals and with long hairs on the outer surface, five shiny, yellow petals, and a ring of 5-10+ yellow stamens around a central mound of yellowish-green pistils. There is often a region at the base of the petals that is translucent and green-tinged. The sepals may lie directly under the petals or may be reflected so they lie parallel to the flower stem. After fertilization, the central mass of the flower enlarges and the other parts of the flower wither and fall away. Maturing fruits are green, shiny, laterally compressed, with a sharply angled margin and long, straight, tapering beaks pointing up at about a 60° angle; the seedhead looks distinctly spikey.

Ranunculus

Ranunculus hispidus

hispid buttercup [Blooms: May-Jul]

Pennsylvania buttercup is a native plant that is formally listed as "imperiled" in Illinois (which is at the southern limit of its range east of the Mississippi). The flowers arise from leaf axils on short stalks. Individual flowers are small (1/8-1/4" across) with five yellowish-green sepals, five shiny, yellow, egg-shaped petals, and a ring of 5-10+ yellow stamens around a central mound of green carpels and pistils. The sepals are longer than the petals, are reflexed back on the flower stem, and are covered with long hairs on the hidden surface. After fertilization, the carpels enlarge and the central mound elongates; individual mature fruits are laterally compressed with straight to sightly curved (but not hooked) beaks. Pennsylvania buttercup tends to prefer wetlands and similar environments.

Ranunculus

Ranunculus pensylvanicus

Pennsylvania buttercup [Blooms: Jul-?]

Cursed crowfoot flowers occur on the ends of the upper stems. Individual flowers are 6-8 mm across with five yellowish-green sepals about the same length as the petals, five (sometimes three or four) yellow, rounded petals, a ring of 5-10+ short stamens with yellow anthers, and a central hemispherical to gumdrop-shaped mass of green pistils. After fertilization, the central mass of pistils enlarges and elongates, producing a cylindrical mass of flat, smooth, kidney-shaped 1 mm long seeds with short, straight beaks.

Ranunculus

Ranunculus sceleratus

cursed crowfoot [Blooms: May-Jul]

Upright prairie coneflower (aka, "Mexican hat") is a 1-3' tall plant native to North America but an exotic in Illinois; it looks like English plantain (Plantago lanceolata) dressed up for a party. The stems are green and longitudinally ridged; they bear alternate, pinnatifid leaves with 5-11 elongate, narrow lobes. The upper stems produce flower stalks (peduncles) 2-12" long, minutely grooved, and lacking leaves; the peduncles are very "wire-like." The flowerheads are 1.5-3" long cylinders composed of numerous brown or purplish disk florets that bloom from the bottom of the cylinder to the top; at the base of the cylinder are 4-12 ray florets with drooping, 1/2-1.5" long, oblong petals with notched tips that are yellow, maroon, or yellow with basal maroon patches (the "party skirt"). This plant is unmistakable when in bloom. The imaged flower was photographed in Bobolink Meadow in July, 2010; I have not seen a specimen since.

Ratibida

Ratibida columnifera

upright prairie coneflower [Blooms: Jul]

Grey-headed coneflower's composite flowerheads sit individually on the tips of long, thin, ridged stalks; they have up to 15 drooping, 2" long, yellow ray florets and a central 3/4" tall gumball- or egg-shaped cone of 100-200 disc florets. The ray florets are sterile; the disc florets have both stamens (5) and styles (1). Beneath the flowerhead are two series of long, narrowly-triangular bracts. The disc florets mature progressively from the bottom of the cone to the top; immature disc florets are light green or grey, mature disc florets are brown, giving the portion of the cone they cover a fuzzy appearance. (Thus the analogy implicit in the common name to a grey, bald pate peeking through a head of brown, fuzzy hair.) After fertilization, the cone becomes a mass of small (2-4 mm long), brown seeds (achenes) that are devoid of a tuft of hairs.

Ratibida

Ratibida pinnata

grey-headed coneflower [Blooms: Jun-Oct]