Herbs, perennial, cespitose, rosulate. Roots branched, dark, not septate, slender, fibrous. Stems sparingly branched, short or elongate. Leaves crowded, in spirals; blade mostly linear, lacunar tissue not evident, base pale, dilated. Inflorescences: scape sheaths tubular, orifice oblique, acute, or 2-cleft; scapes usually several per stem, filiform, glabrous or hairy, hairs neither swollen nor glandular apically; heads white, gray, gray-brown, or brown, ovoid to globose or short-cylindric; receptacle densely pale-pilose; involucral bracts pale to dark, gradate, broad, chaffy, basal ones often reflexed, obscured by inflorescence; receptacular bracts as long as involucral bracts. Flowers: staminate and pistillate on same plants, 3-merous (2-merous in Lachnocaulon digynum); sepals 3, connivent forming club-shaped flower, nearly distinct, spatulate, scarious, apex with club-shaped hairs, surface glabrous or sparsely hairy; petals absent or reduced to small scales or hairs. Staminate flowers: androphore cylindric; stamens (2–)3; apex of staminal column with 2–3 lance-ovoid or peglike, often appendaged glands; filaments adnate to rim of androphore, alternating with glands; anthers 1-locular, 2-sporangiate, dorsifixed, versatile, exserted at anthesis, yellowish or pale. Pistillate flowers: gynophore short; pistil 3-carpellate (2-carpellate in L. digynum); style 1, appendaged at apex, style branches 2–3, 2-cleft, alternating with appendages similar to those of staminate flower.
se United States and Cuba.
Species ca. 10 (5 in the flora).
|1||Apical hairs of receptacular bracts and perianth white, mealy, opaque; heads pale gray to white; scapes hairy (except for glabrous-scaped, s Florida extreme of Lachnocaulon anceps).||> 2|
|1||Apical hairs of bracts and perianth translucent, not white, the brown color of bract and perianth showing through; heads brown or gray-brown; scapes glabrous or with ascending hairs.||> 3|
|2||Leaves narrowly linear, abruptly attenuate; mature heads seldom wider than 4 mm, dull gray-brown or pale gray; scapes glabrous or nearly so distally; seeds dark red-brown, very lustrous, longitudinal ribs faint, transverse ribs forming finely cross-striolate pattern||Lachnocaulon beyrichianum|
|2||Leaves linear, gradually attentuate; mature heads seldom as narrow as 4 mm, whitish to pale gray; scapes pilose from base to apex; seeds pale to dark brown, not lustrous, longitudinal ribs conspicuous, transverse ribs less conspicuous than longitudinal ribs, but coarser than in Lachnocaulon beyrichianum||Lachnocaulon anceps|
|3||Scapes with ascending hairs; heads dull gray-brown; hairs of receptacle copious, partly obscuring flowers (old heads may lose some hairs); gynoecium 3-carpellate||Lachnocaulon minus|
|3||Scapes glabrous; heads either chocolate brown or dull brown, if dull brown, with sepals of pistillate flowers yellow-white, hardly obscured by receptacular hairs; gynoecium 2–3-carpellate.||> 4|
|4||Heads dark brown or reddish brown, usually short cylindric by seeding time; gynoecium 3-carpellate; leaves 2–4 cm; scape sheaths shorter than or as long as leaves||Lachnocaulon engleri|
|4||Heads gray or gray-brown, usually globose by seeding time; gynoecium 2-carpellate; leaves 0.5–2 cm, scape sheaths longer than or at least rising above leaves||Lachnocaulon digynum|