Trianthema

Herbs [shrubs], annual or perennial, glabrous, hairy, or papillate. Roots fibrous. Stems usually prostrate, spreading, branched from base, sometimes woody. Leaves cauline, subopposite, petiolate, those of each pair unequal; stipules attached to margin of petiole, bidentate, usually papery; blade terete or flat, linear to orbiculate, base tapered, margins entire. Inflorescences axillary, flowers solitary or in cymes; bracts foliaceous; bracteoles 2. Flowers inconspicuous, 4 mm diam.; calyx lobes 5, adaxial surface colored, with subapical, abaxial, mucronate appendages; petals and petaloid staminodia absent; stamens perigynous, 5-10[-20], when 5, alternating with calyx lobes; pistil 2-carpellate; ovary superior, 1-2-loculed; placentation basal; ovules 1-12; styles 1-2, longitudinally papillate; stigmas 2. Fruits capsules, dehiscence circumscissile near base; operculum flat, ovoid, or globose, winged or mucronate. Seeds 1-12, brown to black, ridged, triangular, globose, or reniform, smooth or papillate; arils elongate.

Fls perfect, perigynous; sep 5, each usually with a dorsal appendage near the tip; pet none; stamens mostly 5-10; ovary unilocular or bilocular, with accordingly 1 or 2 styles; ovules few; capsule circumscissile; seeds arillate; succulent, shortly taprooted herbs with opposite lvs basally connate into a short sheath with interpetiolar stipules; fls small, solitary or few in the axils. 20, warm reg.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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