Lythrum californicum Torrey & A. Gray, California loosestrife, hierba del cáncer. Perennial herb, rhizomatous, many–stemmed at base from woody rhizome, repeatedly forked in upper canopy, ± erect, in range to 50 cm tall; shoots with only cauline leaves, glabrous.
Stems angled with 4—6 ridges, to 2.5 mm diameter, with 2 winglike ridges descending from each leaf, tough, green.
Leaves helically alternate but often opposite at lower nodes of axillary lateral shoots, simple, sessile and subsessile, without stipules, but having 4 or 6 club–shaped glands in each leaf axil; petiole in range typically < 0.5 mm long, at base colorless stem wing often lobelike at petiole; blade narrowly elliptic to oblanceolate (lower cauline leaves) and narrowly elliptic or narrowly lanceolate (upper cauline leaves), 4—22 × 1.7—5 mm, minutely toothed on margins (10×), acute at tip, pinnately veined with midrib finely sunken on upper surface and raised on lower surface, dull.
Inflorescence racemelike, terminal, flowers 1 per axil of each subsessile, leaflike bractlet; pedicel in range < 0.8 mm long and compressed front–to–back; bracteoles 2, opposite, on lower pedicel, awl–like, ± 1 mm long, reddish, decurrent on pedicel, short–papillate at tip, bractlet and bracteoles early–deciduous.
Flower bisexual, radial, suberect to ascending, ca. 8 mm across; heterostylous; hypanthium (floral tube) at anthesis cylindric, in range 4—4.5 × 1—1.5 mm, 12(10)–ribbed, with minute, winglike, colorless appendages (epicalyx lobes) on alternating ribs; sepals (5—)6, terminal on alternating ribs, deltate, 1 mm (≈ hypanthium appendage length), rose–lavender, with red midrib and papillate on tail–like tip (caudate); petals (5—)6, opposite hypanthium appendages, obovate (oblanceolate), in range 3.5—5 × 1—2.3 mm, orchid to purple (light purple), with a raised, deep purple midvein on lower surface; stamens (5—)6, alternate to petals, ≈ hypanthium length (pin form) or exserted ca. 4 mm (thrum form), free; filaments greenish to whitish; anthers dorsifixed, dithecal, 0.6—0.7 mm long, light yellow–green aging reddish, longitudinally dehiscent; pollen white; pistil 1; ovary superior, sausage–shaped, 1/2 of hypanthium length, green, glabrous, 2–chambered, each chamber with many ovules attached to center; style exserted (pin form) or ≈ hypanthium length (thrum form), of pin form ca. 5 mm long and exserted to 4 mm at anthesis, white; stigma capitate, green.
Fruit capsule, dehiscent by 2 toothlike valves from top, many–seeded, torpedo–shaped, ± 5.5 mm long, hidden by hypanthium, light brown, with bulging seeds.
Seed± ovoid, 1 mm long, biconvex with 1 or 2 edges, tannish.
A. C. Gibson & B. A. Prigge