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Palm sedge fertile culms tend to have fewer leaves (5-10) restricted to the lower half of the culm while infertile culms produce more leaves (8-12+) along their entire length. Fertile culms generate a narrow (5-9 cm long, 1 cm across) inflorescence at their tips bearing 5-12 partially overlapping, stalkless spikelets. Spikelets are 2 cm long, 3-4 mm across prolate spheroids (spindle-shaped); staminate (male) florets are restricted to approximately the bottom quarter of the spikelet while pistillate (female) florets cover the rest of the spikelet. Each spikelet rests on a scale-like bract, only obvious on the lowest spikelet. Perigynia are very large compared to most sedges — 6-8 mm long and about 2 mm across; protruding from the tips of the perigynia are either slender, white styles or pale yellow or white, cylindrical anthers.

Carex

Carex muskingumensis

palm sedge [Blooms: Jun-Jul]

Fertile culms produce a 4-12" long inflorescence at their tip whose central stalk (rachis) is also triangular. Near the tip of the rachis are 1-3 pistillate (male) spikelets 1/2-1.25" long, light green, turning brown with maturity. Below are 2-3 pistillate (female) spikelets each with a leaf-like bract immediately below; the bracts increase in size beneath lower pistillate spikes. The staminate spikelets are usually about 1-3" above the pistillate spikelets, but occasionally appear to grow out of a pistillate spikelet (right). Pistillate spikelets (left) are cylindrical, up to 1.5" long, densely packed with quite hairy, chubby-triangular, perigynia (each 2.5-4" long and about half as wide), and their accompanying bristly bracts. The plants are wind pollinated. Wooly sedge is unusual in its very hairy perigynia; no other Jackson Park sedge has this character.

Carex

Carex pellita

woolly sedge [Blooms: Apr-May]

Fertile culms of Pennsylvania sedge produce an apical inflorescence with a single terminal staminate spikelet 1-2.5 cm long above 1-3 smaller pistillate spikelets and their bracts, all purplish-brown at blooming. Staminate spikelets produce prominent creamy-yellow anthers; pistillate spikelets consist of 4-12 perigynia about 3 mm long and 1.5 mm across, each with 3 white, thread-like styles and a basal, scale-like bract shorter than the spikelet. The lowest pistillate spike bears a basal leaf-like bract usually longer than the spikelet. Florets are wind pollinated.

Carex

Carex pensylvanica

Pennsylvania sedge [Blooms: Apr]

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]

At the apex of the blue cohosh stem is a floral panicle 1-3" long bearing 5-30 flowers. Individual flowers (insert) are about 1/3" (8 mm) across with six petal-like yellow-green sepals, and six stamens with yellow anthers in a ring around a central green ovary and style. The petals have been reduced to six green lobes at the base of the stamens, between the sepals.

Caulophyllum

Caulophyllum thalictroides

blue cohosh [Blooms: Apr-May]

New Jersey tea flowers occur in panicles ("puffballs") up to 5" long and 3" across on peduncles up to 8" long arising from the tip of stems or axils of a leaf. Flowers are 1/4-3/8" across on 1/4-3/4" stalks; each flower has five triangular white sepals folded inwards towards the flower center; five widely spreading, white spoon-shaped petals with narrow bases and broad tips (tips curled in to heighten the "spoon" impression) emerging from between the incurled sepals; five stamens with whitish-purple anthers; and a three-part style.

Ceanothus

Ceanothus americanus

New Jersey tea [Blooms: Jun-Jul]

American bittersweet side branches occasionally produce panicles of flowers (up to 6" long) at their tips. Male flowers are about 1/4" wide with five light green petals with jagged or undulate margins, five green sepals, and five stamens with yellow anthers and a narrow style rudiment.

Celastrus

Celastrus scandens

American bittersweet [Blooms: Jun-Jul]

Common hackberry flowers may be staminate (male), pistillate (female), or perfect (both), all on the same tree. Flowers are about 1/4" across and bloom before the leaves open, often high in the tree (thus, I have no pictures yet). All flowers are wind-pollinated, yellowish-green with 4-6 spreading sepals joined at their bases; there are no petals. Male flowers have 4-5 stamens with green or yellow-brown anthers; female flowers have a green ovary with a large two-part, densely fuzzy style like an umbrella beneath the ovary. Perfect flowers have both.

Celtis

Celtis occidentalis

common hackberry [Blooms: Apr-May]

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-?]

Spotted knapweed has pink to purplish flowers ~3/4" across composed of numerous tubular, branching, sterile ray florets with five lobes; the outermost ray florets are the longest. Disc florets ARE present, shorter and more erect than the ray florets but similar in appearance, with pink to white-tipped anthers and a divided style. The urn-shaped base of the flower is covered with tightly appressed oval bracts, each green with black tips; long, comb-like pale bristles radiate from the tip giving an appearance rather like a tick (inset).

Centaurea

Centaurea stoebe

spotted knapweed [Blooms: Jun-Sep]

Clusters of 4-8 flowers begin to bloom before the leaves emerge on Eastern redbud; the buds (lower left) are rosy-pink, turning a lighter pink when the flowers open. Individual flowers are about 1/2" long, on pedicels 1/4-1/2" long, pea-like with an upper central petal (the banner), two upper lateral petals (the wings) and two lower petals (usually a darker pink) that form the projecting keel; a short purplish tubular calyx with five blunt teeth lies behind the corolla. The keel encloses ten stamens and a single curved style.

Cercis

Cercis canadensis

Eastern redbud [Blooms: Apr-May]

Wild chervil upper stems terminate in up to three clusters of 3-7 small, white flowers (right image). Individual flowers (upper left) are tiny (1/8" across), each with five white petals, five stamens, and a cylindrical green ovary bearing a split style; the sepals are highly reduced. After fertilization, both the cylindrical ovary and the flower stalk elongate; mature fruits (lower left) are usually hairless, about 1/4" long, and contain a single seed.

Chaerophyllum

Chaerophyllum procumbens

wild chervil [Blooms: May-?]

Partridge pea flowers are ~1" across, noticeably asymmetric, with five yellow petals with red blotches at their base; the lowermost petal is about twice the size of the other petals. One of the lateral petals curls around the stamens. There are ten reddish-purple stamens and a single greenish-yellow style (longer than the stamens) that curves upward towards the tip; nine smaller stamens lie on one side of the style and one larger stamen on the other.

Chamaecrista

Chamaecrista fasciculata

partridge pea [Blooms: Jul-Oct]