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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]

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]

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]

Reed canary-grass is a very widespread species (the native range is circumboreal in the Northern Hemisphere) that is listed as "vulnerable" in Illinois. It is a wetland grass that reaches heights of 3-5 feet; plants tend to be widely spaced on Jackson Park although they are known to produce clonal colonies elsewhere. The leaves are flat, alternate, and evenly spaced along the culm. The leaf blades reach up to 12 long and 3/4" across; they are green or blue-gray and hairless with continuous (but rough-textured) margins. The leaf base is much wider than the culm (stem) which it clasps tightly; the leaf sheaths look like an extension of the leaf in both color and appearance. When reproductive (early-midsummer), the culms produce a narrowly-pyramidal panicle up to 10" long and 2-3" across of spikelets that bear the florets. Spikelets are initially green but fade over time to a light tan color. The stem and leaves all turn a diagnostic light tan during the late fall and winter; the leaves mostly remain attached.

Phalaris

Phalaris arundinacea

reed canary-grass [Blooms: May-?]

Hardstem bulrush's inflorescence is a branching cluster (a "pseudoumbel") at the top of the stem with an erect bract at its base that is C-shaped in section and 3/8-3.5" long; the bract appears to be a continuation of the stem. The clusters ("pseudoumbels") may be open or compact, but are more compact than in softstem bulrush. There may be 3-40 spikelets, some solitary (but never all solitary), some in groups of 2-8 at the tips of stiff floral stalks. The spikelets are reddish-brown, 10-17 mm long, cylindrical or spindle-shaped with pointed tips and with 8+ florets spirally arranged on the spikelet. The florets are perfect (both male and female parts present), each with three stamens and a two-part style; each floret is subtended by a single, 3 mm long, red-spotted scale, often with a contorted awn (both of which may be difficult to see — magnification recommended). Hardstem bulrush can tolerate standing water as much as five feet deep. You are most likely to confuse hardstem bulrush and softstem bulrush. The stem in softstem bulrush (Schoenoplectus tabernaemontani) is spongy to the touch and the pith has numerous much larger air cavities than hardstem bulrush in most of the pith. Softstem bulrush has mostly solitary spikelets, a much more open inflorescence, scales covering the florets that are usually not red-spotted, and is a lighter blue green color than hardstem bulrush's dark olive green. Softstem bulrush is much more common in Jackson Park than is hardstem bulrush.

Schoenoplectus

Schoenoplectus acutus

hardstem bulrush [Blooms: Jun-Jul]

Three-square bulrush's inflorescence is a sessile cluster of 1-5 spikelets that sit on one of the flat faces of the culm at a range of angles form ~20° to near 90°. Above the spikelets is a floral bract 2-10" long that looks like a continuation of the culm, but the side of the bract that faces the spikelets has a white-spongy appearance rather than the green of the culm or the other faces of the bract. Individual spikelets are ~1/4-1" (5-20 mm) long, conical in shape, reddish orange or brown when mature, with a chaffy surface. The midvein of the outer scales is extended to form a spiky awn that can be longer than spikelet. Each spikelet contains several perfect florets that are spirally arranged, hard to distinguish externally. Each floret has three stamens, an ovary with a single style divided into 2-3 stigmas, and a covering of chaffy scales; the stamens and stigmas are only present for a brief period before they wither and drop off. The florets are wind pollinated.

Schoenoplectus

Schoenoplectus pungens

three-square bulrush [Blooms: May-Jul]

Fertile great bulrush culms terminate in a sprawling inflorescence up to 6" long and across consisting of a number of branches and branchlets with 15-200 terminal spikelets; at the base of the branches is a single bract 1/2-3" long, C-shaped in cross section, that appears to be (but isn't) a continuation of the culm. The branches and branchlets are light green, flattened, slender, and spreading/drooping. Branchlets end in a single spikelet or a cluster of 2-5 spikelets that are sessile or have short pedicels. Spikelets are 3-17 mm (typically 6-8 mm) long, brown to reddish or orangish brown, and elongate-ovoid in shape; they may appear hairy from remnants of the withered, split styles of the florets. Each floret has a 2.5-3 mm oval brown scale at its base; the scales have a green central vein that may be extended in a short awn. The florets have three stamens and 2-3 styles (split from a single style); they are wind pollinated.

Schoenoplectus

Schoenoplectus tabernaemontani

great bulrush [Blooms: May-Jul]

At the tip of the culm, dark green bulrush produces an inflorescence comprised of one to three (rarely four or five) compound umbels of spikelets; beneath the inflorescence are 3+ leafy bracts (similar to the leaves) that are up to 1' long and 1/2" wide. At least one of the bracts is always longer than the inflorescence. The umbels generate 1/4-4" long, straight branches in all directions that terminate in umbelletes of 5-20 spikelets that rest on slender, leafy bractlets; the spikelets may be sessile or may rest on 1/2" long branchlets. The branches and branchlets are green, straight, and stiff. Spikelets are less than 1/4" long (3-6 mm), ovoid or egg-shaped, yellowish green initially but darkening to brown or black later; the spikelets are an assemblage of numerous spirally arranged, overlapping scales and their florets. The florets each have a single subtending scale, three stamens, and an ovary with a tripartite style; they are wind pollinated. Bulblets may form on one or more branches and sprout late in the season. The umbels may be visually dense and complex and take some study to sort out.

Scirpus

Scirpus atrovirens

dark green bulrush [Blooms: May-Jul]