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Young, densely-hairy, stems of common dewberry terminate in single flowers or corymbs of 2-3 (rarely five) flowers. Individual flowers are 1-1.25" across consisting of five green, lance-shaped, hairy and glandular-hairy sepals with a thin, narrow "tail" at the tip; five white, wrinkled petals longer than the sepals; numerous (20-100) stamens; and a cluster of 5-150 green carpels with their club-shaped styles in the center of the flower. Floral stems may also arise from the axils of leaves. The fruits are pretty typical compound drupes (aggregate fruit like blackberries) 1/2-3/4" across, usually tightly attached to the receptacle with relatively few drupelets (10-40 of the smaller sections of the fruit); ripe fruit are dark red to black and shiny (not pruinose).

Rubus

Rubus flagellaris

common dewberry [Blooms: May-Jun]

Purple-flowered raspberry's flowers are large (up to 2-3") with five sepals densely covered with reddish glandular hairs, bluntly triangular, about half the length of the petals with long, thread-like tips; five magenta, rounded, laterally overlapping petals surrounding a compact ring of 20-100 thread-like stamens with yellow anthers; and a central mound of several hundred pale yellow, club-shaped styles. The fruit is a typical drupe, 3/4" in diameter, reddish-pink when mature, more flattened than a commercial raspberry. It can be hard to find on the plant — it is very popular with birds. Between the maple-like leaves and the showy, magenta flowers, purple-flowered raspberry is impossible to confuse with any other Rubus spp. in Illinois. Purple-flowered raspberry prefers partial shade (like woodland edges); it is critically endangered in Illinois.

Rubus

Rubus odoratus

purple-flowered raspberry [Blooms: Apr/May-Aug]

Second-year canes of Pennsylvania blackberry produce 2-4" (across) corymbs of flowers on the tips of short lateral shoots. Each flower is about one inch wide, has five green, largely hairless, lance-shaped sepals much shorter than the petals with a thin "tail" on their tips; five white, oblong, wrinkled petals, widest about a third of the way from the distal tip; 20-100 creamy stamens with white or yellow anthers; and a light green cluster of numerous (100+) styles. Lance-like stipules or large leafy bracts flank the base of the flower pedicel, the latter often partially hiding the flower. After fertilization, the central cluster of styles enlarges to form a typical blackberry (drupe) 3/4" long, initially white or green but turning black when mature. The fruit is popular with most birds and mammals (including humans), who subsequently disperse the seeds.

Rubus

Rubus pensilvanicus

Pennsylvania blackberry [Blooms: May-Jun]

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]

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]

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]

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]

The tips of the upper stems of common groundsel produce dense clusters of flowerheads on short peduncles; inflorescences can also arise from leaf axils. Common groundsel flowerheads are cylindrical, 8 mm long and 4 mm across, with black-tipped, green bracts around the outside at both the base and the apex and 13-80 yellow disc florets peeking out the end; mature flowerheads are easily mistaken for flower buds. The disc florets have tubular yellow corollas, five stamens fused to the upper part of the corolla with yellow-brown anthers, and a bifurcated style with purplish stigmas. There are no ray florets. This is an easy plant to overlook. The flowerheads are twice as long as wide. The seedhead looks like a compact dandelion tuft with seeds on parachutes of light brown hairs.

Senecio

Senecio vulgaris

common groundsel [Blooms: May-Jul]

The five petals and five sepals of Maryland senna's 3/4" flowers are both yellow. The single pistil has many spreading white hairs and arches upward. The anthers of the 10 stamens are a striking dark brown (like partridge pea). The upper three stamens have short filaments and short anthers that produce only sterile pollen (as a pollinator reward). The middle four stamens have short filaments and long anthers while the lower three stamens have long filaments and long anthers; all seven of these stamens produce fertile pollen that is released by "buzz pollination." The flowers do not produce nectar. The fruit is a flattened seedpod 1/2" across and 3-4" long with 10-18 segments, each containing a single 1/4" flattened seed.

Senna

Senna marilandica

Maryland senna [Blooms: Jul]

Flower buds arise singly or in small groups on 1/2" long peduncles from the leaf axils. Because the flower peduncles are shorter (1/2") than the leaf petioles (1"), the flowers are often partly hidden among the leaves. Individual flowers are about 8 mm across. A flower contains five green, triangular sepals; five light yellow or light orange, rounded, floppy petals with pale lines that function as nectar guides and asymmetrical tips; and a central reproductive column (like mallows, to which prickly sida is related). That column consists of five styles fused along most of their lengths, each with a globose terminal stigma, and numerous stamens with yellow anthers. After fertilization, a circular seedpod forms from the five carpels; when mature, the seedpod turns brown and breaks into five segments, each containing a single reddish-brown, three-angled seed.

Sida

Sida spinosa

prickly sida [Blooms: Aug-Sep]

Evening campion is an exotic from Europe that grows to be 2-3' tall. It is nominally a night-blooming species, but I've observed it in bloom throughout the day in shady areas. Male and female plants are separate. The upper stems end in clusters of one or more 1-1.5" long flowers. The "bladder" (the calyx) is covered with a fuzz of fine hairs and has dark green or reddish-purple lines running from pole to pole (10 lines in male flowers, 20 in female). The five petals are heart shaped (with the point towards the center of the flower) and are deeply cleft into two lobes; the petals form a fringe that makes a distinct collar around the opening to the floral tube. Female flowers have five emergent styles (rarely four or six); male flowers have 10 yellow stamens that barely emerge from the collar at the center of the flower. (Other local Silene sp. have three styles.) The fruit is brown, urn-shaped, and has 10 small teeth on the distal end (or five pairs if you prefer). (Five or six teeth total in S. noctiflora, S. stellata, and S. vulgaris.) Evening campion evolved a dioecious life history (separate male and female plants) about 11 million years ago. (Other species in the genus have "perfect" flowers with both male and female organs present and functional in the flowers.) The evolution and genomic history of the sex-determining Y chromosome (XX = female, XY = male) has been of considerable interest for the light it shines on the evolution of Y chromosomes in both plants and animals (Moraga et al. 2025. Science 387:630–636; Akagi et al. 2025. Science 387:637–643).

Silene

Silene latifolia

evening campion [Blooms: May-Aug]

Royal catchfly's bright red flowers are restricted to the upper regions of the plant as clusters arising from the tips of stems. Individual flowers are 3/4-1" across, have an elongate (1"), narrow, cylindrical calyx with 10 longitudinal ridges, five narrow red or scarlet petals that flare from the tip of the calyx, and stamens with gray anthers that protrude well beyond the opening to the calyx. There are three corkscrew-shaped, threadlike styles that develop after the stamens have matured; like the stamens, they protrude well outside the calyx opening. The fruit is a 1/2" long capsule, open at the top, with 6-8 spreading teeth around the lip. Royal catchfly is hummingbird and butterfly pollinated.

Silene

Silene regia

royal catchfly [Blooms: Jul-Aug]

Starry campion's main stem ends in a panicle of flowers up to 8" long and 3-4" across; additional panicles may arise on the lateral stems on robust plants. Flowers occur in groups of 2-3 on the ends of long, slender branches; the flowers rest directly on short (1/4") pedicels. Individual flowers are 3/4" across. Each flower consists of a bell shaped, light green, fuzzy calyx nearly as broad as it is long with five broad, triangular teeth on its free end; five white petals with a narrow base and a "fringe" of 8-12 narrow lobes on their free ends; 10 stamens with slender white filaments that extend well outside the throat; and three white styles. The styles emerge from a large, green, globular ovary in the middle of the flower. After fertilization, the calyx gets broader (nearly triangular in profile) as the ovary expands into a spherical green ball; the fruit is brown, urn-shaped, and has six teeth on the distal end. The flowers tend to close in bright midday light. They are usually pollinated by moths and, to a lesser extent, bumblebees.

Silene

Silene stellata

starry campion [Blooms: Jun-Jul]

Water parsnip's upper stems end in 2-5" wide, flat-topped umbels of flowers with numerous (10-20) umbellets, each with 20-35 tiny (1/8" wide) flowers. At the base of the umbel are 6-10 narrow bracts that are curved down towards the stem. Each flower has a 3-5 mm long stalk; a short, light green calyx; five white, heart-shaped petals with incurved tips; five stamens that extend well outside the flower; and an ovary with two diverging styles. The fruits are 3 mm long, slightly laterally compressed, oblong, with strong ribbing; each fruit contains exactly two seeds.

Sium

Sium suave

water parsnip [Blooms: Jul-Aug]

Horsenettle's upper stems end in small clusters of 3/4" wide white or light violet flowers with wavy petal margins and hairy pedicels; clusters may also arise from leaf axils. Each flower has a green, hairy calyx with five lobes that taper gradually to sharp tips (typically slightly reflexed); five triangular petals that are fused at their bases; and five yellow, banana-shaped anthers 6-9 mm long surrounding a long, slim, light green style with a darker green, globular terminal stigma. After fertilization, the ovary expands into mature berries about 1/2" in diameter, initially green-striped, that look like yellow cherry tomatoes when mature; they are half enclosed in a papery derivative of the calyx.

Solanum

Solanum carolinense

horsenettle [Blooms: Jun-Aug]

Bittersweet nightshade flowers occur in small (6-12 flowers) clusters arising from the stems and leaf axils. Each flower is about 3/8" across consisting of a small green, purple, or brown calyx with five shallow, triangular lobes; five petals, purple with paired yellow or green spots at their bases, that flare or are reflected backwards over the base of the flower; five bright yellow anthers 4.5-6 mm long that are appressed to form a tight cylinder; and a single green, slender style closely surrounded by the anthers and protruding beyond them. The fruit is a 3/8-1/2" long, oval, tomato-like berry, initially green; mature berries are bright red. The foliage and fruit contain the alkaloid solanum and are toxic; fatalities are rare but have occurred. Horse nettle (S. carolinense) is similar to bittersweet nightshade but has numerous sharp bristles and spines on the stems and leaves that are lacking in bittersweet nightshade. Black nightshade (S. ptycanthum) is also similar but has black (rather than red) mature fruits and white (not purple) petals on the flowers.

Solanum

Solanum dulcamara

bittersweet nightshade [Blooms: May-Aug]

Black nightshade produces solitary umbels 3/4" long usually, from the axils of middle and upper leaves; the flower pedicels are about 3/8" long. Flowers are 1/4-3/8" across consisting of five sepals partially fused at the base of the flower; five white petals, green at their base, sometimes with purple highlights on the outside of the petal, and usually curved backwards; five anthers and their thick filaments appressed to form a tight, bright yellow cylinder with a yellowish-green stem; and a slender style running up the center of the appressed anthers to just emerge from the tip as a green stigma. The fruit is a 1/4-3/8" tomato-like berry, initially green; mature berries are black. The foliage and unripe fruit contain the alkaloid solanum and are toxic.

Solanum

Solanum ptychanthum

black nightshade [Blooms: Jul-Sep]