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Purple loosestrife plants are 2-5' tall. The stems branch frequently, are square in section or ridged, and are very hairy except where the stem is woody. The very showy flower spikes can be up to 20" long. Individual flowers are 1/2-1" wide that are sessile or on very short stalks; there are 5-7 (usually six) purple, wrinkled petals with a dark purple line near their base. (Imagine purple crepe paper.) The long tubular calyx is yellow-green, ridged, and hairy, with five long, narrow teeth at the distal end. Purple loosestrife is "tristylous" — it exhibits three discrete flower morphs that differ in the relative lengths of the stamens and style. Each plant bears flowers of only a single morph. Each morph has two different lengths of stamens — pistil short, stamens long AND stamens intermediate in length; pistil intermediate in length, stamens short AND long; and pistil long, stamens short AND intermediate in length. Tristyly presumably minimizes self-fertilization. Purple loosestrife is a very aggressive, invasive species which crowds out other species. Another invasive which is also called purple loosestrife, Lythrum virgatum, has similar flowers but the leaves narrow towards their base. (L. virgatum is not known to occur — yet — in Illinois.) Do not confuse purple loosestrife with the native winged loosestrife (Lythrum alatum) which has winged stems, smaller flowers (1/2"), hairless foliage, and solitary flowers in leaf axils. It's not as striking a plant as purple loosestrife, but it plays better with its neighbors.

Lythrum

Lythrum salicaria

purple loosestrife [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]

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]

Saltmarsh sand-spurry flowers consist of five elliptical green sepals, five white to pink petals slightly longer than the sepals, 2-5 stamens with bright yellow anthers, and three short (0.7 mm), thread-like styles and three stigmas. In the Great Lakes region, saltmarsh sand-spurry is widely present along roads where salt is used as a deicer. Some sources refer to this plant as Spergularia marina, but ITIS rejects that binomial; Spergularia salina is the accepted name.

Spergularia

Spergularia salina

saltmarsh sand-spurry [Blooms: May-Aug]

Immediately above the terminal stem leaves or leaflets of rue anemons is an umbel of one to six 1/2-1" flowers on 1.5" long pedicels. Each flower has 5-10 white or pinkish-white, petal-like sepals and a striking green center made of 1-16 pistils surrounded by 7-30 stamens with yellow anthers. There are no true petals. The fruit is a cluster of 5-15 strongly ribbed spindles about 8 mm long, pointed at both ends; each contains a single seed. Rue anemone prefers woodlands with dappled sunlight in the spring but tolerates shade in the summer months. The leaflets/leaves of rue anemone are similar to the leaflets of purple meadow-rue (Thalictrum dasycarpum), but you'll never confuse the two; purple meadow-rue blooms six weeks later and is seven feet taller than rue anemone.

Thalictrum

Thalictrum thalictroides

rue anemone [Apr – May]

Large-flowered trillium's single flower sits on a 1-3" long flower stalk; the flower is 3-4" across and leans to one side (but doesn't droop). The flower consists of three green, lance-shaped sepals with rounded bases, three white (pinkish in older flowers) petals with wavy edges, six stamens with golden yellow anthers, a central white ovary, and three styles fused basally but with separated, dull-yellow stigmas. The fruit is a six-angled, globose capsule, about 1/2" long, that is initially green but darkens as it matures; it splits open to release the seeds. The seeds carry an attached oily, fleshy food reward (an elaiosome) and are dispersed by ants which inadvertently deposit the seeds in their nests to take advantage of the reward. Large-flowered trillium prefers shady environments like woodlands and is slow to mature — it can take several years for a sprout to produce flowers.

Trillium

Trillium grandiflorum

large-flowered trillium [Blooms: Apr-May]

The apical flowers of prairie trillium have three green sepals that are reflexed so they point down, three maroon petals, six maroon stamens with dark purple anthers incurved toward the center of the flower, and three purple styles with divergent stigmas hidden from view by the stamens. The fruit is a green, six-angled, ovoid berry 1" long; the seeds have an oily food appendage (an elaiosome) that encourages ants to carry them away. Despite the name, prairie trillium does not occur on prairies; it is a shade-loving, woodland plant like the other local trillium, large-flowered trillium (Trillium grandiflorum). Prairie trillium is superficially similar to toadshade (Trillium sessile), but in toadshade the sepals are spread (perpendicular to the stalk), not recurved (parallel to the stalk, pointed down). In addition, the leaves of toadshade are sessile (no petiole) and rarely have the troutlily-like mottling on the leaves that is seen on prairie trillium. The stamens of toadshade are yellow, not maroon. Toadshade does occur in Illinois, but it is less common, and I have yet to see it in Jackson Park.

Trillium

Trillium recurvatum

prairie trillium [Blooms: Apr-May]

At the top of the Culver's root plant are floral spikes (racemes) up to 10" long covered with small (1/4" long) white, tubular flowers. Individual flowers consist of a short (3 mm long), green calyx with five deep lobes (the lower two lobes longer than the upper three); a tubular corolla with four lobes (the lower two longer than the upper two); two stamens with yellow or reddish brown anthers; and a single style with a tiny stigma. The stamens and stigma protrude well beyond the lip of the flower. The flowers bloom from the base of the floral spike successively towards the tip. The fruit is a 2.5-4.5 mm long ovoid capsule with four apical teeth. The capsules contain 10-30 half millimeter long, ovoid seeds. Culver's root is very popular with a wide diversity of bees.

Veronicastrum

Veronicastrum virginicum

Culver's root [Blooms: Jun-Aug]