Flora of North America species comparison

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Eriocaulon compressum

Eriocaulon nigrobracteatum

flattened pipewort

blackbract pipewort
Habit Herbs, perennial, 20–70 cm. Herbs, perennial, 5–15(–19) cm.
Leaves

linear-attenuate, 5–30 cm, apex subulate.

linear-attenuate, 0.5–1.5(–4) cm, apex subulate.
Inflorescences

scape sheaths mostly longer than principal leaves, loose;

scapes linear, 1–3 mm wide, multiribbed (ribs lacunar);

heads chalk white except for dark gray or near black exserted tips of receptacular bracts, anthers, hemispheric to subglobose, 10–20 mm wide, soft, much flattened when pressed;

receptacle pilose;

involucral bracts frequently squarrose, later obscured by mature bracteoles and flowers, gray, broadly ovate to oblong or elliptic, 2–3 mm, margins entire, apex rounded or obtuse, glabrous;

inner bracts, receptacular bracteoles dark gray, spatulate-linear to oblong, 2–3 mm, margins entire, apex acute with white, club-shaped hairs.

scape sheaths longer than principal leaves;

scapes filiform, 0.3–0.4 mm, 4-ribbed;

mature heads blackish at level of involucre, white above it, hemispheric to globose, 3–4(–5) mm wide, soft;

receptacle glabrous;

involucral bracts spreading, not obscured by bracteoles and flowers, blackish, very lustrous, broadly ovate to orbiculate, 1–3 mm, margins entire to erose, apex broadly rounded, glabrous;

inner bracts, receptacular bracteoles blackish or with pale base, broadly to narrowly ovate, 2–3 mm, margins somewhat erose with age, apex rounded or apiculate, margins and abaxial surfaces with white, club-shaped hairs, apically ciliate.
Staminate flowers

sepals 2, pale or with dark apex, linear or linear-spatulate, 2–4 mm, apex acute to blunt with mealy white, club-shaped hairs;

androphore broadly club-shaped;

petals 2, pale, oblong, conspicuously unequal, larger lobe apically fringed with pale, club-shaped hairs, smaller lobe glabrous or with a few hairs at apex;

stamens 3–4(–6);

anthers black.

sepals 2, gray-brown, broadly spatulate to oblong-obovate, curved, keeled, 1–1.2 mm, keel and margin with white, club-shaped hairs;

androphore club-shaped to campanulate, flaring;

petals 2, oblong-obovate, nearly equal, 1 mm, apex ciliate and abaxially with white, club-shaped hairs;

stamens 4;

anthers black.
Pistillate flowers

sepals 2, dark at apex, oblong-spatulate, 2.5–3 mm, abaxially with mealy white, club-shaped hairs, adaxially with translucent hairs;

petals 2, pale, oblong-spatulate, apex acute, abaxially with mealy white, club-shaped hairs, adaxially with translucent hairs;

pistil 2-carpellate.

sepals 2, gray, oblong, curved, keeled, 1 mm, adaxial surfaces pilose, hairs translucent, sharp, apically with white, club-shaped hairs;

petals 2, pale, short-stipitate or nearly sessile, oblong, 1 mm (narrower and longer than those of E. koernickianum), apex obtuse, adaxial surface and margins with white, club-shaped hairs;

pistil 2-carpellate.
Seeds

dark lustrous brown, broadly ovoid to near round but asymmetric, 0.5 mm, mostly minutely spiny-papillate.

brown, nearly round, 0.3 mm, obscurely reticulate, alveolae irregularly and horizontally rectangular.

Eriocaulon compressum

Eriocaulon nigrobracteatum
Phenology Flowering late winter–spring. Flowering spring.
Habitat Sands and peats of shallow pineland ponds, savanna, seeps, ditches, or low flatwoods Muck of deep sphagnous seep bogs in longleaf pinelands
Elevation 0–300 m (0–1000 ft) 0–100 m (0–300 ft)
Distribution
from FNA
AL; DE; FL; GA; LA; MD; MS; NC; NJ; SC; TX
[WildflowerSearch map]
[BONAP county map]
from FNA
FL
[BONAP county map]
Discussion

Eriocaulon compressum is polymorphic in habit. Male flowers vary considerably in length and degree of connation, and female flowers are often sterile. Of the southeastern coastal plain species this and the similar, but proportionately smaller, E. lineare, are the most aquatic, the former most common around clay-based ponds, the latter around karst ponds. Unlike the more northern E. aquaticum, these two species seldom frequent the shallows of flowing streams.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Eriocaulon nigrobracteatum is a very limited, local endemic whose relationships with E. aquaticum should be clarified.

Of conservation concern.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 22. FNA vol. 22.
Parent taxa Eriocaulaceae > Eriocaulon Eriocaulaceae > Eriocaulon
Sibling taxa
E. aquaticum, E. cinereum, E. decangulare, E. koernickianum, E. lineare, E. microcephalum, E. nigrobracteatum, E. parkeri, E. ravenelii, E. texense
E. aquaticum, E. cinereum, E. compressum, E. decangulare, E. koernickianum, E. lineare, E. microcephalum, E. parkeri, E. ravenelii, E. texense
Synonyms E. decangulare, E. gnaphalodes, E. cephalotes, Sphaerochloa compressa
Name authority Lamarck: in J. Lamarck et al., Encycl. 3: 276. (1789) Orzell & E. L. Bridges: Phytologia 74: 105, figs. 1–4. (1993)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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