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Fragrant water lily flower stalks, like the leaves, develop directly from the rhizomes. Flowers are 3-6" across; they have four greenish-white sepals that rest on the water's surface; 15-40 brilliant white (occasionally pink) petals in multiple series; 35-120 stamens with bright yellow anthers distributed around the inner circumference of tthe flower; and a central stigmatic disc on the floor of the flower at the base of the stamens. Flowers open and close daily. The fruit is 1-2" long and globoid; its stalk bends downward so the fruit develops underwater. After the tiny seeds (~1/16-1/8") are released, they float for some time, dispersed by wind and water currents, then sink to the bottom of the water body where they germinate.

Nymphaea

Nymphaea odorata

fragrant water-lily [Blooms: May-Aug]

Eastern prickly pear is the commonest of three prickly pears native to Illinois, all quite rare. Eastern prickly pear can grow to be as much as 2' tall but Jackson Park specimens rarely exceed 6". Flowers are 2-3" across consisting of numerous yellow, satiny tepals, the innermost layer with reddish-orange highlights towards the tepals bases, 50-1500 stamens with pale yellow anthers, and a single style topped with a ring of six fleshy, white stigmas. Each flower lasts a single day. Fruits are initially green but turn reddish-brown when mature; they are 1-2" long, less than 1" in diameter, and concave on the top.

Opuntia

Opuntia humifusa

Eastern prickly-pear [Blooms: Jun-Jul]

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]

In buckthorn, umbels of flowers arise from leaf axils. Flowers on a single plant may be perfect (both male and female organs present), but more commonly the flowers are dioecious with either all male (staminate) or all female (pistillate) flowers found on any given plant. Individual flowers are 1/4" across. They have four greenish-yellow, triangular, spreading sepals that together form a calyx and four petals that can't be easily seen without magnification; the "petals" in the flowers are actually sepals. Male flowers have four greenish stamens with cream-colored anthers; female flowers have a single style that has a tip divided into four branches. After fertilization, female (or perfect) flowers produce a shiny black, 1/4" wide, cherry-like fruit containing 3-4 seeds. Birds can eat the fruit without ill effects, but in humans the fruit produces stomach cramps and acts as a strong laxative (as indicated by the species name, "cathartica").

Rhamnus

Rhamnus cathartica

buckthorn [Blooms: May-Jun]

Rosinweed produces a panicle of sunflower-like blooms from the top of the stem and the tops of side stems (if any). Individual flowerheads are 2-3" across; they consist of 12-35 yellow, pistillate (female) ray florets and 70-200+ functionally male disc florets. The green bracts beneath the flowerheads are teardrop-shaped, partially overlapping in two or three layers, and sometimes covered with glandular hairs. The petals of the ray florets have two prominent longitudinal grooves and a tiny apical notch. Only the ray florets can produce seeds — a split style protrudes from a short tube at the base of the ray floret. The central disk is initially green but becomes yellow as the disk florets open; they are yellow, tubular, with five triangular lobes at their free end, with a column of brown stamens with the tips of very long, (non-functional) styles protruding from the tubular corolla. The fruit is a flat seed that develops from the ray florets. (The curious arrangement where only the ray florets can produce seeds while the disk florets are functionally male is true throughout the genus Silphium. The opposite is true in the true sunflowers, genus Helianthus.)

Silphium

Silphium integrifolium

rosinweed [Blooms: Jul-Sep]

A cup plant may have 10-30 flowerheads in bloom at one time. Behind the flowerhead are two or three layers of green bracts; the outer layer is egg shaped with a triangular, pointed, recurving tip. Each sunflower-like flowerhead is about 3-4" across; it has 18-40 yellow ray florets (e.g., the petals) and 85-150 yellow disk florets. The ray florets have a bifurcated but functional style protruding from a short yellow tube at the base of the petal; the disc florets are initially green but transform into yellow, tubular corollas with a non-functional style protruding through the fully-functional stamen. (True throughout the genus Silphium. The opposite is true in the sunflowers, genus Helianthus, where the ray florets are functionally male and the disk florets are fertile, functional females.) The cup-like leaves and square stem distinguish cup plants from other prairie wildflowers.

Silphium

Silphium perfoliatum

cup plant [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-?]