Lechea tenuifolia Michx., narrow–leaved pinweed. Perennial herb, from taprooted caudex, many–stemmed at base, branches ascending, to 20 cm tall; shoots with only slender cauline leaves, conspicuously strigose and short–strigose.
Stems cylindric, to 1.5 mm diameter (green stems < 1 mm diameter), wiry, short–strigose with upward–pointing hairs.
Leaves helically alternate, simple, short–petiolate, without stipules; petiole on short–projecting leaf base, cylindric, < 1 mm long, pale green to pinkish, strigose; blade linear, 3—8 × 0.4—1 mm, long–tapered at base, entire, acute often with reddish callus at tip, 1–veined raised on lower surface, upper surface glabrous, lower surface with photosynthesis tissue indented and textured, strigose.
Inflorescence leafy raceme (panicle of racemes), terminal and axillary, raceme several–flowered, without bracts, strigose on all green sides and surfaces; bract subtending raceme = cauline leaf; peduncle stemlike, to 6 mm long; pedicel cylindric, to 3 mm long.
Flower bisexual, irregular, 1.5—2 mm across; sepals 5, dimorphic, outer 2 sepals at slightly different points of attachment, linear–oblanceolate, 1.8—2 × 0.3—0.35 mm, > flower bud, green, upper surface glabrous, lower surface strigose and with short stiff hair at tip; inner 3 sepals tightly overlapping and in bud appearing 3–sided, overlapping briefly spreading, 2 boat–shaped and keeled, in range 1.5—1.8 mm long, green and rose with 1—2 membranous margins where overlapped, other inner sepal broadly ovate and not keeled, green and membranous, outer (lower) surface and strigose, inner (upper) surface glabrous; petals 3, oblong–obovate, ± 1.7 × 0.7 mm, ± rose but white at fleshy base, lacking veins, rounded to minutely notched at tip; stamens 3—8, free; filaments to 2.3 mm long, crimson, conspicuously beaded; anthers dorsifixed, dithecal, 0.3—0.35 mm long, crimson, longitudinally dehiscent; pollen orangish; pistil 1; ovary superior, short–obovoid but somewhat 3–sided, 0.65 × 0.5 mm, green (rose), sometimes with 6 dimples, glabrous, 3–chambered, each chamber with 2 ovules; style erect, 0.2 mm long, green to midpoint and red above midpoint, with 3 stigmas forming a dish with feathery edges, ca. 0.8 mm across, rose–red.
Fruit capsule, loculicidal, dehiscent by 3 valves, 2—5–seeded, subspheroid, ca. 1.8 mm.
Seed elongate D–shaped, ± 1 mm long, reddish brown.
A. C. Gibson