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Narrowleaf willow is dioecious — plants produce either all male or all female inflorescences (catkins) with the florets (male or female) spiraling around the catkin axis in a pseudo-whorl. Catkins are produced on one-year-old branches at the same time the leaves emerge. Male catkins are cylindrical, 3/4-2" long; they may be either erect or lean to one side but generally are ascending. Female catkins are also cylindrical, 1.5-3" long, initially green but turning light brown on maturity; they are usually terminal spikes on the new season's growth. Individual male florets consist of a single yellow, silky-hairy, oblong bract (quickly shed) and a pair of stamens with bright yellow anthers; the lower parts of the filaments are also covered by silky hairs. Individual female florets also have an oblong, basal bract that is shed; above that is a 1 mm long slender stalk supporting a bottle-shaped ovary 5-9 mm long with a pair of flat stigmas at its apex that appear to be four. After fertilization, the catkin elongates, and the ovary develops into a capsule that splits longitudinally to release the seeds when they are mature.

Salix

Salix interior

narrowleaf willow [Blooms: Apr-Jul]

Black willow is dioecious — plants produce either all male or all female inflorescences (catkins) on one-year-old branches; the catkins emerge with the leaves. Male catkins are 1-3" long, cylindrical, yellow to greenish-white, and usually curved. Female catkins are greenish are 1-3" long, elongating as they mature. Both male and female florets are numerous and arranged in pseudo whorls around the axis of their respective catkins; neither has either sepals or petals. Individual male florets have 3-6 stamens with yellow, globose anthers and a pale yellow, oval basal bract shorter than the stamens. Individual female florets also have a pale yellow, oval basal bract; a hairless, flask-shaped pistil 3-5 mm long is elevated above the bract on a 0.5-1.5 mm long (short!) pedicel and has a single style and a pair of stigmas at its tip. After fertilization, a capsule enlarges, finally splitting longitudinally to release the seeds with their attached cottony hairs.

Salix

Salix nigra

black willow [Blooms: ??]

Upper branches of elderberry end in flat to domed panicles of flowers 3-10" across. Individual flowers are about 1/4" across, with a green, cup-shaped calyx, a creamy white corolla with five petal-like lobes, five long, spreading stamens with white anthers, and a creamy white hemispherical ovary with 3-5 short styles; flowers occur in umbel-like panicles 10" across made of dozens of flowers. The fruits are <1/4" wide spherical drupes in starburst-like sprays, dark purple to black when mature. The flower stalks are light green, turning purplish as the fruit ripens. The raw fruit is sweet with a slightly bitter or astringent aftertaste but may induce nausea or diarrhea if eaten in more than small quantities. The fruit is widely used in a variety of herbal supplements (as infusions and extracts), jam, and herbal wine. Note that all parts of the plant including the sap (except the flesh of the fruit) contain toxic cyanide-producing glycosides; berries should be cooked before consumption.

Sambucus

Sambucus nigra

elderberry [Blooms: May-Jul]

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]

The tips of the upper stems of Canadian black snakeroot give rise to umbels 2.5" across of greenish white flowers; each umbel usually consists of 1-4 umbellets, each with 2-3 pistillate flowers or perfect flowers and 2-6 staminate flowers. In perfect flowers, the pistils develop (and are deployed) before the stamens develop; the pistillate stage persists for much longer. Each flower has a green calyx with five lance-like lobes slightly longer than the five greenish-white petals. Male and perfect flowers add five stamens with white anthers and lack the series of hooked spines of the pistillate flowers. Female and perfect flowers have ovaries densely covered with distinctive, neatly stacked series of long, hooked bristles arrayed perpendicular to the axis of the flower. The fruit is round, 3-5 mm long, covered in rows of those same hooked bristles; it splits on maturity to release the two seeds.

Sanicula

Sanicula canadensis

Canadian black snakeroot [Blooms: Jun-Jul]

On black snakeroot, one to five 1/2" wide globoid umbels (flower clusters) arise from the tips of the upper stems. Each umbel is packed with 20-60 tiny flowers and their flower stalks (pedicels). In each umbel, 1-3 flowers are "perfect" (with both male and female organs) and the rest are staminate (stamens only). In addition to the male stamens, the perfect flowers have two long, cylindrical styles (emerging from a hidden ovary) that arch and recurve from the middle of the flower; the styles are much longer than the hooked bristles on the ovary. Both staminate and perfect flowers have a minute (<1 mm) green calyx with five rounded teeth, five dull yellow to greenish-yellow, heart-shaped petals (tip of the heart towards the center of the flower), and five protruding stamens <3 mm long with obvious yellow (or brown) anthers. The fruit is a 1/4" long round to cylindrical bur covered with short, hooked bristles; the remains of the styles often persist. The bur splits to release the two seeds inside.

Sanicula

Sanicula odorata

black snakeroot [Blooms: May-Jun]

Soapwort produces clusters of 3/4-1" flowers from the tips of terminal stems and branches. Individual flowers have a 1" long, green or reddish, sometimes hairy, cylindrical calyx; a corolla with five spreading (later reflexed), pink to white, oblong petals/lobes with a notched tip; 10 white stamens with pale yellow anthers that protrude from the throat of the flower; and a similarly protruding, divided white style. The calyx persists as an inflated seed capsule filled with 15-75 tiny dark brown, kidney-shaped seeds. Soapwort might be mistaken for a phlox, but the stamens and style in phlox are always hidden in the calyx tube, never protruding as in soapwort, and soapwort has leaves with three obvious longitudinal veins. Soapwort contains saponins in both the foliage and (especially) the seeds that make a frothy soap-like lather when boiled (and were once used as a soap substitute), but caution is recommended — the saponins are toxic. Herbivores generally avoid this plant.

Saponaria

Saponaria officinalis

soapwort [Blooms: Jun-Jul]

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]

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]

Early figwort (aka, lanceleaf figwort) is difficult to distinguish from late- (or Maryland-) figwort (S. marilandica) except by blooming date (before July = early, after July = late, July = could be either) and details of the flowers (especially the sterile stamen). The inflorescence (a panicle) is constructed from short, spreading, sparse branches covered in glandular hairs, bearing a 3/8" long, shiny tubular flower whose outside surfaces are reddish-purple to reddish-green and inner surfaces are reddish brown (upper and lateral lobes) or greenish yellow (lower lobe). Four yellow, fertile stamens and a single blunt, slender style hug the floor of the flower, the style protruding further than the fertile stamens. A single sterile stamen (a "staminode") is located along the upper interior of the flower. The sterile stamens are yellow or green with a broad tip in early figwort (S. lanceolata); they are reddish-brown to purple and narrow in late figwort (S. marilandica). The fruit is a teardrop-shaped capsule, dark brown when mature, that splits in two longitudinally to release the numerous tiny seeds.

Scrophularia

Scrophularia lanceolata

early figwort [Blooms: May-Jul]

Late figwort's inflorescence (a panicle) gives rise to short, spreading, sparse branches covered in glandular hairs, bearing a 3/8" long, shiny tubular flower whose outside surfaces are reddish-purple to reddish-green and inner surfaces are reddish brown (upper and lateral lobes) or greenish yellow (lower lobe). Four yellow, fertile stamens and a single blunt, slender style hug the floor of the flower, the style protruding further than the fertile stamens. A single sterile stamen (a "staminode") is located along the upper interior of the flower. The sterile stamens are yellow or green with a broad tip in early figwort (S. lanceolata); they are reddish-brown to purple and narrow in late figwort (S. marilandica). The fruit is a teardrop-shaped capsule, dark brown when mature, that splits in two longitudinally to release the numerous tiny seeds.

Scrophularia

Scrophularia marilandica

late figwort [Blooms: Jul-Aug]

Mad-dog skullcap flower racemes may arise at the tips of the stems or from the axils of leaves. Each raceme is up to 6" long, containing 6-7 pairs of flowers; each flower has a short, basal leafy bract. Flowers are up to 8 mm long with a short, slender pedicel, a light green tubular calyx with two shallow lobes (the upper lobe with a dish-like projection), and a pale blue, lavender, or white, densely hairy, tubular corolla 5-8 mm long with a short, hood-like, upper lip and a slightly flared, three-lobed lower lip. Hidden inside the upper lip of the corolla are four stamens and a single bifurcated style. After fertilization, the calyx swells into a green capsule with includes the dish-like projection mentioned above, giving the capsule a unique appearance; inside is a cluster of four nutlets. The mouth of the calyx is visible as a thin slit beneath the projection.

Scutellaria

Scutellaria lateriflora

mad-dog skullcap [Blooms: Jul-Aug]

Crown vetch's flower stalks are about 6" long with a 1" wide cluster (an umbel) of 10-25 pea-like flowers on short (1/4") pedicels, all attached to the tip of the flower stalk. Each flower is 1/2" long and 1/4" wide, with a short green calyx bearing five pointed lobes and a typical pea-like corolla, bicolored in pink and white. The five petals are modified as a vertical standard (often pinker than the other petals, which are white), two lateral wings, and a pair of abutting petals forming a medial keel perpendicular to the standard. Within the keel are 10 stamens (one free and nine fused to each other, all with small yellow anthers) and a slender style, curved upwards, with a tiny terminal stigma. The fruit is a 1/2-2" long, narrow seedpod (loment) with 1-7 slightly constricted segments and a long terminal "beak" (the remains of the pistil); the pods remain attached to the flower stalk, forming a cluster often likened to "fingers". The tight flower clusters with showy, bicolored flowers are characteristic.

Securigera

Securigera varia

crown vetch [Blooms: Jun-Sep]

Biting stonecrop (aka, mossy stonecrop) is an exotic succulent that is native to Greenland and western Europe but naturalized across most of the U.S. and the lower Canadian provinces. It is a mat-forming plant with creeping stems that roots at nodes; the stems produce short, erect vegetative and flowering stems. The leaves are alternate, sessile, and densely imbricated on the erect stems; they are green or yellowish-green, with old, white leaves persisting. The succulent-like leaves are 4-5 mm long, 2.5-3 mm across, and 1.5 mm thick, convex on both the upper and underside and blunt-tipped. The inflorescence arises from the tip of one of the erect stems; it is about 5/8" (1.5 cm) long, 1/4-1.25" (5-30 mm) across, with 1-3 branches, each with 1-4 sessile (or on 1 mm long pedicels) flowers with a basal bract. The sepals closely resemble the leaves. The flowers have five bright yellow petals, typically 10 stamens with yellow anthers, and 4-5 yellow pistils, each with a single style and a pinhead-shaped stigma. The fruit is a five-pointed yellowish star of united, inflated follicles filled with numerous seeds. Biting stonecrop is not a good competitor; it grows best in thin, dry soils like cliffs, shingle, and beaches. However, it is tough — it stores water in its leaves and reportedly can go six months without external water.

Sedum

Sedum acre

biting stonecrop [Blooms: Jun]