Eriocaulon

Herbs, annual or perennial, often cespitose, rosulate. Roots: larger roots unbranched, pale, septate, thickened, spongy. Stems rarely sparingly branched, short or elongate. Leaves many ranked in flat or high spiral; blade basally pale, distally greener, linear-attenuate or triangular-acuminate, lingulate, narrowing gradually or abruptly from base, base noticeably lacunate, less distinctly so distally. Inflorescences: scape sheaths tubular, orifice oblique (often 2–3-cleft); scapes 1–several per rosette, glabrous; heads pale to dark, white, gray, or gray-brown, hemispheric to globose or short-cylindric; receptacle hairy or glabrous; involucral bracts obscured or not obscured by inflorescence, pale to dark, chaffy or scarious; receptacular bracts narrower, thinner than involucral bracts, often scarious. Flowers mostly with staminate and pistillate on same plants, 2–3-merous; sepals 2(–3), adnate to stipelike base, boat-shaped, scarious, apex often covered with multicellular hairs, hairs mealy white or translucent, frequently club-shaped; petals 2(–3), narrower, shorter than sepals, apex hairy, hairs club-shaped, glands adaxial, subapical, dark, rarely pale. Staminate flowers: androphore apically dilated stalk; petals separated from sepals by androphore, diverging as lobes from apex; stamens 3–4 or 6, 2–3 alternating with petals; apex of staminal column with 2–3 glands, glands unappendaged; filaments arising from androphore rim; anthers 2-locular, 4-sporangiate, dorsifixed, usually versatile, well exserted at anthesis, jet black (except in E. cinereum). Pistillate flowers: gynophore separating petals from sepals, stipelike; pistil 2(–3)-carpellate; style 1, unappendaged, style branches 2(–3).

Distribution

Mostly pantropic, mostly aquatic or on wet, mainly acidic substrates.

Discussion

Species ca. 400 (11 in the flora).

Selected References

None.

Lower Taxa

Eriocaulon aquaticum, Eriocaulon cinereum, Eriocaulon compressum, Eriocaulon decangulare, Eriocaulon koernickianum, Eriocaulon lineare, Eriocaulon microcephalum, Eriocaulon nigrobracteatum, Eriocaulon parkeri, Eriocaulon ravenelii, Eriocaulon texense

Key

1	Receptacle and/or base of flowers copiously hairy; some or most receptacular bracts and perianth parts with chalk white hairs; heads white, 5 mm or more in full flower or in fruit.	> 2
1	Receptacle and/or base of flowers glabrous or sparingly hairy; receptacular bracteoles and/or perianth glabrous or hairy, hairs club-shaped, clear or white; heads dark gray or white, usually less than 7.5 mm in full flower or in fruit.	> 4
2	Heads hard, very slightly flattened when pressed; scape sheaths shorter than most leaves; involucral bracts straw-colored, apex acute; receptacular bracteoles pale, apex narrowly acuminate; pistillate flower petals adaxially glabrescent; terminal cells of club-shaped hairs of perianth whitened, basal cells often uncongested, transparent; plants of moist but seldom aquatic or permanently wet situations	Eriocaulon decangulare
2	Heads soft, much flattened when pressed; scape sheaths longer than most leaves; involucral bracts gray or dark, apex rounded or obtuse; receptacular bracteoles gray to dark gray, apex acute; pistillate flower petals adaxially villous; all cells of club-shaped hairs on perianth mealy white; plants in aquatic or wet substrates.	> 3
3	Mature heads 10–20 mm wide; leaves 5–30 cm; petals of staminate flower conspicuously unequal	Eriocaulon compressum
3	Mature heads 5–10 mm wide; leaves (1–)2–5(–7) cm; petals of staminate flower nearly equal	Eriocaulon texense
4	Stamens 6, pistil 3-carpellate.	> 5
4	Stamens 4, pistil 2-carpellate	> 6
5	Anthers yellow; apex of receptacular bracteoles acute	Eriocaulon cinereum
5	Anthers black, apex of receptacular bracteoles obtuse	Eriocaulon microcephalum
6	Heads 4–10 mm wide at maturity; outer involucral bracts usually reflexed, obscured by bracteoles and flowers.	> 7
6	Heads seldom as wide as 5 mm; outer involucral bracts not reflexed, not obscured by bracteoles and flowers.	> 8
7	All bracts of staminate and pistillate flowers straw-colored or pale with grayish midzone; sepals of pistillate flowers basally pale, darkening distally to grayish, gray-green, or gray-brown; heads (young or mature) very pale; seeds faintly rectangular-reticulate, often papillate in lines; s coastal plain	Eriocaulon lineare
7	Inner involucral bracts, receptacular bracts, and sepals darkened, usually gray to near black; young heads dark; seeds very faintly reticulate, not papillate; n and/or montane	Eriocaulon aquaticum
8	Bracts straw-colored, greenish, or light gray to gray, dull, margins often erose or lacerate, apex blunt to obtuse; scapes linear; plants of brackish substrates	Eriocaulon parkeri
8	Bracts dark, gray to blackish, very lustrous, margins all nearly entire (except Eriocaulon nigrobracteatum), apex acute; scapes filiform; plants of acidic substrates.	> 9
9	Bracts narrowly ovate to oblong or spatulate, apex acute; bracts and perianth parts (except petals in some cases) glabrous; seed conspicuously pale-reticulate	Eriocaulon ravenelii
9	Bracts wider in outline, apex rounded or apiculate; bracts (margins and apex) and perianth hairy; seed not pale-reticulate.	> 10
10	Petals of pistillate flowers stipitate, suborbiculate-rhombic; outer involucral bracts straw-colored, inner and receptacular bracts dark gray, gray-green, or gray-brown	Eriocaulon koernickianum
10	Petals of pistillate flowers short-stipitate or nearly sessile, oblong; involucral and receptacular bracts blackish or with pale base	Eriocaulon nigrobracteatum