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Cyperus sedge's fertile culms develop an inflorescence at their tips 1.5-6" long consisting of a single staminate spikelet up to 3" long and 2-6 pistillate spikelets 3" long and 9-12 mm across. The pistillate spikelets are initially erect but later droop (especially the lowest pistillate spike, which has the longest pedicle). At the base of each pistillate spike's pedicle is a leaf-like bract up to 20" long. Perigynia of the pistillate spikes are oriented perpendicular to the axis of the cylindrical spikelet, 3.5-6 mm long and 1-2 mm wide, not inflated, lance-shaped with two strong 1 mm long teeth at their tips. (Insert) - Three fuzzy stigmas protrude from the tips of the perigynia.

Carex

Carex pseudocyperus

cyperus sedge [Blooms: Jun-Jul]

A fertile culm of star sedge (right). Most culms are fertile, generating an apical inflorescence 1.5-3" long with 3-8 spikelets more closely spaced the higher their position on the inflorescence. Spikelets consist of 1-9 perigynia, 3 mm long and 1.5 mm wide, each initially erect, but later rotating so they point in all directions. (Thus, the species name "radiata.") At the base of each spikelet is a needle-like, long, narrow bract. The bracts are longer the further the spike is from the tip of the inflorescence; the bract beneath the most basal spikelet may be as long as the entire inflorescence. The male florets (lower left image; note the club-like anthers) occur above (more distal than) the female florets in the spikelet; the latter have a pair of 1 mm long styles protruding from their tips (upper left image; the fuzzy stigmas are beginning to wither in this image).

Carex

Carex radiata

star sedge [Blooms: May-?]

Fertile culms produce an apical inflorescence up to 12" long bearing 1-3 staminate (male) spikelets 1-2 cm long with 3 anthers and 2-5 pistillate (female) spikelets 1.5-3 cm long. The pistillate spikelets are roughly cylindrical overall with 10-30 perigynia 4-7 mm long radiating in all directions from the axis; each perigynium has an inflated, nearly-spherical base and a long, tapering, sharp distal beak.

Carex

Carex sprengelii

longbeaked sedge [Blooms: Apr-May]

Two prickly sedge inflorescences photographed about a month apart. Fertile culms bear an apical inflorescence from 2-4" long bearing several short spikelets with a distinctly spikey appearance; the spikelets are initially light green (left image) but turn gold (right image) to brown as they mature. Each spikelet has a needle-like bract at its base (longest in the lowermost spikelet); the spikelet has a few staminate (male) perigynia apically but the majority of the perigynia are pistillate.

Carex

Carex stipata

prickly sedge [Blooms: May-Jun]

Brown fox sedge fertile culms apically bear a 2-5" long, 15 mm wide inflorescence (bottom) with numerous spikelets variably spaced along the axis. All spikelets have staminate (male) flowers apically and pistillate flowers below with a bristle-like bract at their bases; the lowest bract is the longest (up to 2"). Perigynia (top) are 2-3 mm long and 1.5 mm across, tapering to a toothed beak; pistillate scales as long as the perigynia with terminal awns add to the bristly appearance.

Carex

Carex vulpinoidea

brown fox sedge [Blooms: May-Jul]

Pecan trees have separate male and female flowers on the same tree. The staminate (male) catkins droop from short spurs on the twigs; they typically develop in groups of three and are about 4-6" long with numerous staminate florets along the catkin. Individual staminate florets have a three lobed bractlet arising from their base that shelter the 4-6 stamens that hang beneath it; the middle lobe is the longer of the three lobes. The pistillate (female) spikes develop at the tips of a subset of the twigs, each spike bearing 3-10 greenish, pistillate florets; the florets are 1/4" long and 1/8" across. Each pistillate floret contains a short, tubular calyx, four bractlets of unequal sizes, and a pistil with two feathery stigmas. Each bractlet has four erect to spreading, lance-shaped lobes. The pistillate florets are wind pollinated. Fertilized florets transform into 2-6 greenish fruits (nuts in a husk) in a cluster, each with four short wings; when mature, the ovoid fruits are about 2" long and 1" across, brown or black in color; the husks partially divide into four segments along the wings, releasing the nut. Pecan is typically a bottomland tree that lives in river valleys but can grow in any rich, moist, well-drained soil. The leaves of black walnut and pecan have a similar number of leaflets in their odd-pinnate leaves, but the fruits are completely different. According to the Arnold Arboretum at Harvard, pecan trees (Carya illinoinensis) can live for over 300 years. For some reason, Carya illinoinensis is the state tree of ...... Texas.

Carya

Carya illinoinensis

pecan [Blooms: Jun-Aug]

Sandburs are no one's friend. They are a form of grass with light green culms, round in section, up to 2.5' long; they are mostly covered by the sheaths of the alternate leaves. Each culm and upper branches (if any) terminate in a 4" long (3/4" across) raceme of 4-20 spiky burs. Each 1/4" diameter bur (excluding the spines) consists of 2-3 spikelets, each containing a fertile flower recognizable only by the stamens or styles protruding from the tip of the spikelets. The flowers are wind pollinated. This is the only sandbur in Illinois, so identification is easy (if not always painless).

Cenchrus

Cenchrus longispinus

sandbur [Blooms: Aug-?]

Chicory flowerheads are an unmistakable clear blue, 1-1.5" across, sessile or on very short stalks, with 10-20 (typically 17) blue ray florets with five tiny teeth at their tips; there are no disc florets. Two series of small bracts covered with glandular hairs cup the base of the flowerhead. In the center of the flowerhead are spike-like, deep-blue stamens (one for each ray floret) fused around a style, each style with a light blue, bifurcated stigma. The flowerheads open in the morning but usually close later in the day.

Cichorium

Cichorium intybus

chicory [Blooms: Jun-Sep]

Field bindweed stems produce 1-4 funnel-shaped flowers, each arising from a leaf axil, about 1" across and cupped by five small sepals and attached to a flower stalk; the flower stalk bears two small bracts about 1" below the base of the flower. Flowers range from white to pink, with a clear yellow center containing five stamens and a single style with a split stigma. Each bloom lasts only one day.

Convolvulus

Convolvulus arvensis

field bindweed [Blooms: May-Aug]

American hazelnut flowers. The male inflorescence is a cylindrical catkin that appears in the fall on the most recent year's twigs and then overwinters; in the spring, the catkin elongates (to 2-4" long) and the male flowers (consisting of two tiny bracts and four stamens) open to release their pollen. The female inflorescence looks like a small bud protected by bracts that is located at the branch tip or in leaf axils; it contains several pistillate flowers seen only as red styles/stigmas protruding from the tip of the "bud."

Corylus

Corylus americana

American hazelnut [Blooms: Mar-Apr]

Shining flatsedge is an attractive plant up to 10" tall with sprawling culms up to 8" long, triangular in section. The flower spike (inflorescence) has 2-7 strikingly laterally-flattened spikelets 1/4-1/2" long; each spikelet has 8-18 reddish-brown floral scales arranged in two opposing rows, each covering a floret consisting of 2-3 stamens, an ovary, and a split style which may protrude 1-2 mm beyond the scales. The plant is wind pollinated.

Cyperus

Cyperus bipartitus

shining flatsedge [Blooms: Aug-Sep]

Yellow nut sedge flower spikes are 2-3" long with spikelets sticking out at 90° to the axis and 90° to each other around the axis (producing four somewhat irregular rows down the axis). The axis itself is flattened with narrow wings. Individual spikelets are 1/2-3/4" long, yellow- or golden-brown, flattened, with from10-30, 2-3 mm long scales, each covering a floret. Each floret has a white, tripartite style with curly ends (the stigmas) and three stamens with yellowish-brown anthers; the flowers are wind pollinated.

Cyperus

Cyperus esculentus

yellow nut sedge [Blooms: Aug-?]

Rusty flatsedge produces an umbel comprised of 3-6 floral stalks 1-4" long bearing clusters of 2-4 floral spikes. (Visually, this looks much like the branch of a fir tree.) Individual spikes are 1/2-1.5" long with individual needle-like spikelets 1/2-1" long pointing in all directions (like a bottle brush). Each spikelet has 8-25 scales sheltering perfect florets (i.e., both three stamens and a tripartite style are present). Spikelets are initially yellow- or whitish green, becoming reddish-brown at maturity. (Thus the "rusty" name.)

Cyperus

Cyperus odoratus

rusty flatsedge [Blooms: Aug-Sep]

Flat-topped aster produces stems that are 2-5' tall and unbranched except at the inflorescence, a flat-topped cluster of small (1/2"-3/4") white flowers with few (2-15) broad but sparse ray florets ("petals"). The disc florets are initially yellow but become cream-colored with age. The branching of each stem produces a flat-topped panicle of flowerheads that is 3-12" across. Individual flowerheads are small (1/2-3/4" across) with 5-12 white ray florets around 12-25 yellow disc florets (but these may fade to a yellowish-tan color as the disc florets age). The base of each flowerhead is surrounded by appressed, oblong bracts ("phyllaries") in 2-4 layers ("series").

Doellingeria

Doellingeria umbellata

flat-topped aster [Blooms: Jul – Sep]

in common spike-rush, at the tip of the culm is a single spike, elongate-ovoid with a sharply pointed tip, up to about 1" long; 30-100 florets ( each with three stamens bearing dark yellow anthers and a split style) are spirally arranged around the spikelet, each protected by a pointed scale 3-5 mm long. The scales have a green to straw-colored midrib, reddish- or orange-brown flanks, and a translucent edge. The two lowest scales in the spike lack flowers. The lowest scale wraps less than 3/4 of the base; it is mostly green bordered by a brown band and a translucent, rounded edge and is more leathery than other scales.

Eleocharis

Eleocharis palustris

common spike-rush [Blooms: May-Jul]

Jerusalem artichoke should rightly be called a "sunflower" like the other four members of the genus Helianthus present in Jackson Park. Five to fifteen flowerheads ride on hairy peduncles up to 8" long and are 2.5-3.5" across; each is cupped by 2-3 overlapping series of phyllaries (bracts) that are more triangular than lance-shaped, hairy, and sharply pointed. The flowerheads consist of 10-20 sterile, yellow ray florets; the 60+ fertile disc florets consist of tubular yellow corollas about 1/4" long with five lobes at their apex and five protruding brown or black anthers fused around a yellow style with a bifurcated stigma. Jerusalem artichoke was cultivated by the indigenous peoples of the midwest for its tasty and carbohydrate-rich tubers.

Helianthus

Helianthus tuberosus

Jerusalem artichoke [Blooms: Aug – Oct]

Duckweed is a tiny, floating flowering plant (one of the smallest in the group) that is present on the lagoons and Columbia Basin from May through October. The flower is highly reduced — about 1 mm across consisting of a cup-shaped scale, a pair of tiny stamens, and a single pistil; I have never observed it. (The flowers are rarely produced — most reproduction is vegetative.) The combination leaf and stem is oval, 2-5 mm long and 1.5-3.5 mm across with a single rootlet up to 2 cm long dangling from the underside. Unless you have a good magnifying glass or microscope, further detail will not be useful.

Lemna

Lemna minor

duckweed [Blooms: ?]

Lyme grass flower spikes are 5-14" long, initially blue-green or silvery but turning beige when mature. There are typically one pair of spikelets per node on the spike. The spikelets are 1/2-1" long, containing 2-5 (typically 3) florets; each floret contains two bottlebrush-like styles and 1-3 stamens, each typically with a single yellow anther. Like all grasses, Lyme grass is wind pollinated. Lyme grass is very similar to the native American dune grass (Leymus mollis) but the latter is greener and is finely hairy under the spike. Lyme grass has become established in sandy habitats around the Great Lakes and (curiously) along the coast of Greenland.

Leymus

Leymus arenarius

Lyme grass [Blooms: May-Jun]