Dalea candida Michx. ex Willd. (white prairie clover)

Petalostemon candidum Michx. ex Willd.

Pl. 392 c, d; Map 1727

Plants perennial herbs, with a knotty, dark brown to black caudex above a stout taproot. Stems 1–4, (20–)40–70 cm long, erect or slightly arched, unbranched or sparingly branched above the midpoint, prominently ribbed, glabrous, sparsely gland-dotted. Leaves 1.5–6.0 cm long, sometimes appearing in fascicles, with 2 smaller trifoliate leaves at the base of the main leaf. Leaf blades with the rachis 10–30 mm long, gland-dotted, those of the main leaves with (3)5–11 leaflets. Stipules 1–5 mm long. Leaflets 5–30 mm long, 2–7 mm wide, those of the lower leaves often larger than those of the upper leaves, linear to narrowly oblong or elliptic-oblanceolate, usually tapered at the base and tip, occasionally blunt but with a minute, sharp extension of the midvein at the tip, the upper surface glabrous, the undersurface gland-dotted but otherwise glabrous. Inflorescences dense spikes (the axis not visible between the flowers), 2–6 cm long, ovoid to cylindric, the stalk 5–11 cm long, the axis glabrous or occasionally minutely and inconspicuously hairy (viewing the axis requires removal of flowers or fruits), with scattered bracts and a whorl closely subtending the spike, these persistent, 4–10 mm long, 0.5–1.2 mm wide, linear to long-tapered above a slightly expanded base, green, gland-dotted, more or less pale-margined, grading into the bracts subtending flowers, these prominent in bud but shed early, 5–6 mm long (longer than the calyces of the associated buds), 1.5–2.0 mm wide, long-tapered above a narrowly elliptic-oblanceolate to obovate base, gland-dotted, the margins thin and pale. Calyces with the tube 1.9–2.5 mm long, glabrous, the ribs often reddish-tinged, gland-dotted around the rim, the lobes 1.0–1.8 mm long, linear to narrowly triangular, often reddish-tinged, the margins minutely hairy. Petals white, the banner with the expanded portion 1.5–2.0 mm long, the wing and keel petals similar, attached along the rim of the stamen tube, the expanded portion 1.8–2.0 mm long. Stamens 5, the filament tube 2–3 mm long, the free filaments 2–3 mm long, the anthers yellow. Fruits included in the persistent calyx or more commonly somewhat exserted, 2.5–4.0 mm long, firm above the membranous basal portion, with a transverse ring of glands separating the two regions. 2n=14. June–September.

Scattered nearly throughout the state, but uncommon in the western portion of the Glaciated Plains Division and the Mississippi Lowlands (North Dakota to Texas east to Wisconsin and South Carolina; Canada). Upland prairies, glades, tops of bluffs, openings of mesic to dry upland forests, and savannas; also pastures, cemeteries, railroads, and roadsides.

Dalea candida is sympatric with D. purpureum throughout most of its range. This complex and widely dispersed species is very similar to D. multiflora, which has more numerous, shorter spikes. Dalea occidentalis (Rydb.) L. Riley}, a closely related taxon that occurs mostly to the west of the range of D. candida (Montana to Arizona east to North Dakota and Texas; Canada) has sometimes been treated as a western variety, D. candida var. oligophylla (Torr.) Shinners. It differs most noticeably in its spikes that become somewhat less dense with age and its more sharply ribbed, hairier calyces.