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Star of Bethlehem's unopened flower buds bear alternating green and white triangles on the enclosing tepals that make the species easy to ID even before the flowers open. Flowers are about 3/4" across with six tepals, white on the top surface and the margins of the underside, green along the centerline of the tepal's underside; six stamens with yellow to brownish anthers whose filaments are flattened to form a visually-striking picket fence topped by sharp points; and a single pistil with a six-ridged yellow ovary and a single yellowish-green style. The fruits are three-celled with six exterior ridges, initially looking like the bottom of a miniature green bell pepper. The flowers produce lots of nectar; they tend to open before noon and close before sunset (or much earlier on cloudy days). Star of Bethlehem is an escapee from cultivation and is competitively quite aggressive. This species produces toxic cardiac glycosides throughout the plant but especially in the flowers and bulbs; it has been reported to have poisoned unwary sheep.

Ornithogalum

Ornithogalum umbellatum

star of Bethlehem [Blooms: May]

Butterweed stems produce a flattened panicle of flowers about 6" across with a single series of bracts (phyllaries) surrounding the base of the flowerhead. Individual flowerheads are 1/2" across with 5-15 yellow, narrowly-oblong pistillate ray florets and 35-50+ yellow, tubular disk florets with five apical lobes a single style that extends just past the anthers, and five stamens attached to the inside of the tubular corolla; the disk is 4-5 mm across. The fruit is a single, five-angled seed with a tuft of white hairs (like a dandelion). Butterweed contains toxic compounds (probably pyrrolizidine alkaloids) which deter most mammalian herbivores (although some domestic herbivores do eat it and suffer the consequences). According to ILW, butterweed was typically restricted to southern Illinois, with a few recent occurrences in central Illinois. Apparently, it has now made its way to Cook County. Butterweed (Packera glabella), balsam ragwort (Packera paupercula), and prairie ragwort (Packera plattensis) are easy to confuse — all bloom in the late spring/early summer and all are weedy-looking plants with yellow/golden-yellow, daisy-like flowers. With one exception, the flowers don't help to distinguish them; however, the petals of butterweed, seen from behind, have a strap-shaped blade with 2-3 teeth at the distal end and a narrow tube (the corolla tube) about a quarter the length of the strap connecting the strap to the rest of the flower (not present in the ragworts). In general, you'll need to look carefully at the leaf shape and presence/absence and quantity of wooly fine white hairs on the leaves and stems. Butterweed has large (10" long) basal leaves; the leaves are pinnatifid with multiple semicircular lobes and a circular terminal lobe. Balsam ragwort (Packera paupercula) basal leaves are no longer than 3", the flowerheads have 0, 8, or 13 ray florets, the phyllaries behind the flowerhead are purple-tipped, and wooly hairs are usually found in the leaf axils. Prairie ragwort (Packera plattensis) is extensively covered with white wooly hairs on the stems, leaves, leaf axils, and on the phyllaries behind the flowerheads.

Packera

Packera glabella

butterweed [Blooms: May-Jun]

Mature wild quinine plants are 2-3' tall. On the flowering stalks (and the side branches) are flat topped clusters of white, button-like flowerheads about 3/8" across. (The Illinois Wildflowers website considers them "similar to a head of cauliflower.") Flowerheads are composed of 15-35 disk florets, often with blackish, club-like stamens poking out; the 5-6 ray florets bear a tiny, cup-shaped petal and a pistil with a bifurcated stigma. No other wildflower in Illinois has flowerheads anything like wild quinine; common and widespread in Jackson Park.

Parthenium

Parthenium integrifolium

wild quinine [Blooms: May-Aug]

Mayapple produces a single, hairless stem that branches no more than once; each stem thus has either a single leaf (infertile stems) or two leaves (fertile stems). Fertile stems produce a solitary nodding flower, 2-3" across, that is hidden beneath the leaves where the two leaves branch on the stem. The flowers contain 6-9 brilliant white petals and a ring of 12-18 tan stamens with large, banana-shaped anthers, all surrounding a surprisingly large, yellow ovary topped with a button of a stigmata. The fruit is a large (1.5" long), ellipsoidal berry, yellow when ripe. All parts of the plant are poisonous including the green fruit, but the ripe (yellow) fruit is edible (in small quantities).

Podophyllum

Podophyllum peltatum

mayapple [Blooms: Apr-May]

Solomon's seal is a 2-3.5' tall plant with a single, unbranched, hairless, arching stem. On the underside of the stem are 12-20 dangling clusters of flowers (2-3 flowers/cluster). The flowers are 1/2-1" long, whitish- or yellowish-green, tubular, with six lobes/tepals fused for most of their length but that flare slightly at their tips; the interior of the flower contains six stamens with yellow anthers and a single style. The fruit is a 1/4" diameter spherical berry, initially green, dark blue-violet or -black when mature. When in bloom or bearing fruit, Solomon's seal is distinctive and easy to identify; when not in bloom, the leaves of Solomon's seal can be difficult to distinguish from those of false Solomon's seal (Maianthemum racemosum) and starry false Solomon's seal (Maianthemum stellatum). (Both Maianthemum sp. have short petioles on their leaves and their flowers are terminal, at the end of the stem, rather than hanging down from the stem.) Polygonatum biflorum is sometimes (incorrectly) referred to as Polygonatum commutatum. The "Solomon's seal" in the name refers to scars on the rhizome fancied to look like a Hebrew seal. I have to admit I just don't see it.

Polygonatum

Polygonatum biflorum

Soloman's seal [Blooms: May-Jul]

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]

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]

Pennsylvania buttercup is a native plant that is formally listed as "imperiled" in Illinois (which is at the southern limit of its range east of the Mississippi). The flowers arise from leaf axils on short stalks. Individual flowers are small (1/8-1/4" across) with five yellowish-green sepals, five shiny, yellow, egg-shaped petals, and a ring of 5-10+ yellow stamens around a central mound of green carpels and pistils. The sepals are longer than the petals, are reflexed back on the flower stem, and are covered with long hairs on the hidden surface. After fertilization, the carpels enlarge and the central mound elongates; individual mature fruits are laterally compressed with straight to sightly curved (but not hooked) beaks. Pennsylvania buttercup tends to prefer wetlands and similar environments.

Ranunculus

Ranunculus pensylvanicus

Pennsylvania buttercup [Blooms: Jul-?]

Upright prairie coneflower (aka, "Mexican hat") is a 1-3' tall plant native to North America but an exotic in Illinois; it looks like English plantain (Plantago lanceolata) dressed up for a party. The stems are green and longitudinally ridged; they bear alternate, pinnatifid leaves with 5-11 elongate, narrow lobes. The upper stems produce flower stalks (peduncles) 2-12" long, minutely grooved, and lacking leaves; the peduncles are very "wire-like." The flowerheads are 1.5-3" long cylinders composed of numerous brown or purplish disk florets that bloom from the bottom of the cylinder to the top; at the base of the cylinder are 4-12 ray florets with drooping, 1/2-1.5" long, oblong petals with notched tips that are yellow, maroon, or yellow with basal maroon patches (the "party skirt"). This plant is unmistakable when in bloom. The imaged flower was photographed in Bobolink Meadow in July, 2010; I have not seen a specimen since.

Ratibida

Ratibida columnifera

upright prairie coneflower [Blooms: Jul]

Cutleaf coneflower (aka, green-headed coneflower) is an imposing tallgrass prairie plant, 3-8' tall, that can form dense stands. The composite flowerheads are 2-3" across. Eight to fifteen light green, oblong bracts lie beneath a central globe-like, light green to yellow cone surrounded by 6-12 yellow, drooping, sterile ray florets. The disk florets have yellow to yellowish green corollas and a protruding bifurcated stigma; the stamens are yellow, fused to the base of the corolla, with deep purple anthers attached around the styles side-by-side. Immature disk florets are green (thus the alternative common name); mature disk florets produce a spikey appearance. The disk florets mature from the bottom of the cone to the top, lending a pincushion-like appearance to the cone.

Rudbeckia

Rudbeckia laciniata

cutleaf coneflower [Blooms: Jul-Sep]

Sweet coneflower flowerheads are 2-3.5" across, occurring as single blooms on the tips of stems or branches. A flowerhead is comprised of numerous 1/2" long medium green, lance-shaped phyllaries, downy with short hairs; 10-20 bright yellow, oblong, sterile ray florets with a tiny notch at their tips; and a deep brown hemisphere of 200-400 disk florets (the central disc). The disk florets have a tubular, dark reddish-purple corolla; bifurcated stigmas that have sharp tips; with the purplish-brown anthers adhering side by side around the deep purple styles. Sweet coneflower is distinctive among the Jackson Park coneflowers with its chocolate brown disk and bright yellow, elongate-oval petals with a shallow notch at their tips.

Rudbeckia

Rudbeckia subtomentosa

sweet coneflower [Blooms: Jul-Aug]

Brown-eyed susan is a native bushy plant that branches at the leaf axils and produces prodigious numbers of small flowers, up to 5' tall. The stems are deep reddish brown and covered with long white hairs. The leaves are alternate, twice as long as wide, lance-shaped, up to 4" long and covered by short, stiff hairs that give it a rough texture. Some lower leaves are three-lobed, sometimes deeply, and halberd- or trident-shaped. Upper stems terminate in one or two flowerheads, 1-2" across. Each flowerhead has an underlying inner and outer series of eight (total) green bracts with hairs along the margins; 6-13 golden-yellow, sterile ray florets, often with a small notch in the tips of the oval petals; and a central cone of 150 to over 300 purplish-brown, cylindrical disc florets with five stamens and short, blunt, bifurcated stigma. If in doubt, brown-eyed susan tends to be taller than black-eyed susan, with fewer petals (6-13 vs. 8-20) and smaller flowers.

Rudbeckia

Rudbeckia triloba

brown-eyed susan [Blooms: Jun-Sep]

Pale dock produces an inflorescence 4-12" long at the tip of the stem; branches in the inflorescence are few but are densely covered with numerous whorls of 10-20 small (1/8-1/4" long), green or yellow-green flowers drooping on 1/8-1/4" long pedicels. Individual flowers have six green tepals (three sepals and three similar petals) that spread at flowering to expose either six stamens or three styles, but close again after pollination. (Flowers are either pistillate (female) or staminate (male) and are wind pollinated.) After fertilization of the pistillate flowers, the fruit — a single seed in the middle of three equally-spaced wings — replaces the flower. Pale dock's seeds can persist in the soil for at least ten years.

Rumex

Rumex altissimus

pale dock [Blooms: May-Jun]

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]

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]

White blue-eyed grass is a native perennial, 6-12" tall with a tuft of basal leaves and flowering stalks that are grass-like (if you squint). The basal leaves are green, 1/8" across, and strap-like; they are shorter than the flowering stalks. The flowering stalks are weakly winged and have a pair of sessile spathes (bracts sheltering the inflorescence) at their tips. The spathes consist of a pair of 1" long reddish or light brownish green bracts backed by a 3" long leafy bract; an umbel of up to six flowers arises between the bracts but only one or two flowers are in bloom at any given time. Each flower is only about 1/2" across and is supported by a 1/2" long pedicel. The flower consists of six white or pale blue tepals with a yellow patch at their bases and narrow, dagger-like tips; a column of yellow or orange-yellow stamens fused along their length almost to the anthers; and a globoid, green ovary covered with fine hairs and sporting a style with three slender lobes. Fertilized flowers produce a ridged, globoid seed capsule, initially green but turning tan to brown as it matures.

Sisyrinchium

Sisyrinchium albidum

white blue-eyed grass [Blooms: May-?]