Filtered (85)
Pickerel weed is an aquatic plant with emergent leaves and flower spikes; it is native to the New World. Each flower stalk is up to 3' tall (usually shorter) and bears a single leaf whose petiole is wrapped by a thin sheath. The flower stalks bear a flower spike ~5" long, densely covered with blue-violet flowers and unopened flower buds; below the spike, the flower stalk is wrapped in a sheath. Individual flowers are ~1/2 across; the corolla has three upper lobes (with 1-2 yellow spots on the middle lobe) and an additional three lower lobes; the exterior of the buds and the flowers is covered with long, white hairs. There are six stamens, usually three emergent and three recessed deep in the flower. Like purple loosestrife (Lythrum salicaria), pickerel weed has tristylous flowers with each plant producing flowers with one of three distinct lengths of the styles (and thus the position of the stigma) and three complementary lengths of the stamens (call them long, medium, and short). If the styles are L, the stamens are M and S; if the styles are M, the stamens are L and S, and if the styles are S, the stamens are L and M. Presumably, these complications enhance genetic outcrossing. For more information, see Price and Barrett (1984) Biol. J. Linn. Soc. 21: 315-329 and Gettys and Wofford (2008) J. Heredity 99: 558-563.

Pontederia

Pontederia cordata

pickerel weed [Blooms: Jun-Sep]

Silverweed is a low, sprawling native plant that occurs everywhere in North America from the southwest through northern Canada. The prominent red stolons give rise to both new rooted nodes where the stolons encounter wet soil and may also give rise to new leaves. There is a basal rosette of large (12" long x 4" wide) odd-pinnate leaves with 5-11 opposite leaflet pairs and a single terminal leaflet. Flower pedicels 2-6" long arise from stolon nodes. The flowers are bright yellow, solitary, and 3/4" across. Each flower has five light green, hairy sepals; 5-15 oval, yellow petals; a ring of ~20 yellow stamens with large flat anthers; and a central disc of 20 to over 100 yellow pistils. The sepals are shorter than the petals. Silverweed prefers sandy habitats like beaches.

Potentilla

Potentilla anserina

silverweed [Blooms: Jun-Aug]

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]

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]

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]

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]

The inflorescence at the tip pf the stem in curly dock produces branching clusters with numerous whorls of 10-25 flowers dangling from slender pedicels. Flowers are tiny (1/8-1/4"), red- or yellow-green, with six tepals (three sepals and three very similar petals), three styles, or six stamens, or both; the flowers droop from a 1/4" pedicel. (The flowers are either pistillate (female), staminate (male), or perfect (both male and female organs). The flowers are wind pollinated. The tepals spread out when the flowers are mature, exposing the stamens and/or styles, then close up after pollination. The fruit is a single seed sandwiched in the center of three heart-shaped, papery membranes (derived from the tepals) set at 120° from each other, dark brown when mature. Note that more mature curly dock fruit can take on a distinct reddish tint, superficially looking like bitter dock fruit, but curly dock fruits will never show the long tooth- or finger-like projections from the edges of the wings that bitter dock exhibits.

Rumex

Rumex crispus

curly dock [Blooms: May-Jun]

The inflorescence of bitter dock is a panicle of whorled racemes up to 1' long. The greenish-red flowers droop from 1/2" pedicels. Individual flowers are 1/4" long with six tepals (six sepals and six similar petals) with pistillate (female) and male (staminate) flowers mixed in each inflorescence. Pistillate flowers have a single pistil, three styles with fringe-like, divided stigmas, and inner tepals that are (often) red; staminate flowers have six stamens and dull yellow inner tepals. After fertilization, the inner tepals of the pistillate flowers enlarge and surround an expanding, hard-shelled, three-sided seed with three membranous wings, each wing with 2-4 spiny teeth along their free edges. The fruits turn bright red as they mature.

Rumex

Rumex obtusifolius

bitter dock [Blooms: May-Jul]

Common arrowhead's flowering stalks are about as tall as the leaves, either angular or round in section. Branches of the inflorescence end in 2-5 whorls of 2-3 flowers; the terminal branch bears 3-9 whorls of 2-3 flowers. Beneath each whorl 2-3, 1/8-1/3" long, boat-shaped, green floral bracts unite. Male (staminate) flowers have 25-30 yellow stamens while female (pistillate) flowers have a central green sphere of carpels; the male flowers are located above the female flowers in each raceme. Perfect flowers (both male and female organs present) do occur but are rare. Individual flowers are about 1-1.5" across with three oval, green sepals and three rounded, white petals about twice the length of the sepals. Male flowers have 7-30 yellow stamens in the center of the flower; female flowers instead have a bur-like green cluster of hundreds of carpels and their spike-like pistils (which have terminal or lateral styles). The pistils form a dense spiral on the surface of the central green mass. After fertilization, the female flowers lose their petals and transform into a bur-like, brown fruit about 3/4" across when mature; the spikes on the bur are individual seeds (achenes) that have a large, fang-like projection at right angles to the main axis of the seed.

Sagittaria

Sagittaria latifolia

common arrowhead [Blooms: Aug – Sep]

Bloodroot flowers are 1.5-3" across with 8-16 (typically 8) bright white petals, numerous stamens with golden yellow anthers, and an oval, green pistil with a pale yellow, two-lobed stigma at its tip. Two light green sepals are present in the floral bud but they drop off as soon as the flower begins to open. After fertilization, the ovary expands into a spindle-shaped seed capsule about 1" long, yellow when mature, that splits to release the seeds. The seeds are disbursed by ants that are attracted by the white, fleshy appendage (an elaiosome) on the bright red seed. The red sap is highly toxic, both externally and internally — it inhibits the cellular Na+/K+ ATPase enzyme and kills the cells. Avoid getting the sap on your skin and certainly avoid getting it in your eyes or on mucous membranes.

Sanguinaria

Sanguinaria canadensis

bloodroot [Blooms: Mar-Apr]

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]

Alpine squill is a 4-8" tall early spring plant, native to Eurasia. Alpine squill has two (rarely three or four) 3-6" long, narrow, curved, fleshy leaves. One to six red-brown, hairless, leafless flower stalks arise from between the basal leaves; each stalk supports 2-10 deep blue, erect flowers less than 1/2" across on individual, hairless pedicels. The basal leaves clasp the flower stalks up to about half their length. Each flower faces upwards (unlike Scilla siberica), has six spreading tepals, six stamens with dark blue anthers, and a single pistil. The stamens are distinctive in that the filaments are flattened along the flower's radial axis and taper distally; from the side they look like isosceles triangles with the anthers on their tips. Alpine squill contains cardiac glycosides; all parts of the plant are highly toxic.

Scilla

Scilla bifolia

alpine squill [Blooms: Mar-Apr]

Siberian squill is another of the early spring ephemerals native to the Caucasus and west Asia that has been wildly successful in northern Illinois and parts of Minnesota, displacing native species. Its leaves are restricted to a basal set of 2-3 leaves about 5" long and 1/4-1/2" wide, linear with a blunt tip, a shiny green surface, and smooth margins. The leaves tend to roll inward along their margins with the curl increasing towards the tip of the leaf. One or more purplish-green, 6" tall flower stalks arise from the center of the ring of basal leaves with single (rarely two or three) blue, nodding flowers on each stalk, suspended from a slender pedicel that arises directly from the unbranched flower stalks. Each flower is about 1" across with six flaring blue (rarely, white) tepals (each typically with a dark blue line down the middle), six white stamens with dark blue anthers, and a single green pistil with an undivided blue style. Siberian squill can be confused with alpine squill (Scilla bifolia), but in alpine squill the flowers face laterally or upwards rather than drooping like Siberian squill, and the flower stalks are distinctly red-brown (rather than brownish green) and branched rather than supporting flowers with a simple pedicel. Despite the common name, Siberian squill is not native to Siberia; it is native to a broad swath of western Europe from Turkey through the Caucasus and southwestern Russia. Sources differ on whether Siberian squill is toxic but note that it is avoided by vertebrate herbivores; proceed with caution.

Scilla

Scilla siberica

Siberian squill [Blooms: Mar-Apr]

Compass plant flower stalks are very hairy, have scattered sessile, triangular bracts, extend vertically multiple feet, and bear 3-4" yellow, sunflower-like composite flowers. There are 20-35 yellow ray florets (e.g., petals) and 100-200+ yellow, tubular disk florets. Behind the flowerheads are two or three layers of very hairy, green, lance-like bracts with sharply pointed, recurved tips. For unknown reason (it just IS), only the ray florets are fertile; the disc florets bear only functional stamens (with a non-functional style protruding through the middle of the 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.)

Silphium

Silphium laciniatum

compass plant [Blooms: Jun-Sep]

Prairie dock's hairless flower stalks produce a panicle of buds and flowerheads. The flowerheads are 2-3" across, with 15-30 bright yellow ray florets with pointed tips and two grooves running the length of the petals; a yellow central disc about 1/4-1/3 the width of the flower contains 120-140 disk florets, green when still buds but bright yellow when open. Behind the flowerhead are two or three layers of green, egg or teardrop shaped, hairless bracts. The ray florets have a bifurcated but functional style protruding from a short yellow tube at the base of the petal; the disc florets have tubular corollas with a non-functional style protruding through the 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.)

Silphium

Silphium terebinthinaceum

prairie dock [Blooms: Jun-Sep]

Hedge mustard flowers occur at the tips of long, slender flower stalks that curve upward; the flower stalks typically arise in abundance at the top of the plant. Each flower is small (1/4" across) with four greenish-yellow sepals, four rectangular yellow petals with rounded tips, a single stout style, and six stamens. The fruit is a very slender, cylindrical seedpod (silique) lower on the flower stalk than the blooming flowers; the siliques are 3/8-3/4" long, erect, oriented parallel to and often appressed to the flower stalk, with the remains of the style on their tips. The siliques turn light brown when mature and split open to release the seeds. The short (<3/4"), straight, appressed seedpods and the upward-curving, sparse flower stalks with only a few blooms open at any one time distinguish hedge mustard from other local mustards.

Sisymbrium

Sisymbrium officinale

hedge mustard [Blooms: May-Jul]