Flora of North America species comparison

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Trichophorum cespitosum

Trichophorum

trichophore cespiteux, tuft bulrush, tuft clubrush, tuft clubsedge

bulrush, club-rush, deergrass, trichophore
Habit Plants densely cespitose; rhizomes absent. Herbs, perennial, cespitose, rhizomatous or not.
Culms

grooved, terete, 5–45 cm, smooth.

trigonous or terete.
Leaves

basal sheaths brown;

distal leaf sheaths concave at mouth;

blades 1.5–8 × 0.3–0.4 mm, much shorter than culms at flowering and fruiting.

basal or subbasal;

sheaths bladeless or distal sheaths with blade to 5 mm, not fibrous;

ligules present;

blades obsolete or elongate, linear, less than 1 cm × 1 mm.
Inflorescences

spikelets 3–9-flowered, 3.3–7 × 1.2–3 mm;

bracts equaling spikelets, 3.3–4.5 mm, apex with awn less than 1 mm.

terminal;

spikelets 1;

involucral bracts 1, suberect, scalelike, apex mucronate or awned.
Spikelets

scales reddish brown to dark brown, apex mucronate to acute.

scales 3–9, spirally arranged, each subtending flower.
Flowers

perianth bristles 6, brown, terete, equaling or exceeding achenes, smooth to scabrous;

anthers 1.5–2.6 mm.

bisexual;

perianth of 0–6 bristles, straight, shorter than to about 20 times as long as achene, smooth or scabrous;

stamens 3;

styles linear, 3-fid, base persistent.
Achenes

compressed trigonous, 1.4–1.7 × 0.6–0.9 mm.

trigonous or plano-convex.
2n

= 104.

Trichophorum cespitosum

Trichophorum
Phenology Fruiting summer (May–Aug).
Habitat Open, wet, rocky or peaty meadows, fens, bogs, shores
Elevation 0–2100 m (0–6900 ft)
Distribution
from FNA
AK; ID; ME; MT; NC; NH; NY; OR; SC; TN; UT; VT; WA; AB; BC; MB; NB; NL; NS; NT; NU; ON; PE; QC; SK; YT; montane c Asia; Greenland; Europe; boreal w Asia
[WildflowerSearch map]
from USDA
North America; Circumpolar to circumboreal; Andean and tropical Southeast Asian mountains
[BONAP county map]
Discussion

Segregates defined on the basis of characters such as the number of flowers per spike and distal leaf sheath morphology have been recognized at varietal or subspecific ranks in North America and Europe. In North America, at least, these characters are variable within populations and appear to have no geographic integrity. North American plants of Trichophorum cespitosum appear to be identical to subsp. cespitosum (cf. R. A. DeFilipps 1980). No cytological differences have been detected between European and North American populations; all counted plants have 2n = 104 or n = 52.

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

Species 9 (6 in the flora).

The appropriate name and typification for this genus have been debated widely. Arguments for conservation of Trichophorum Persoon in the sense used here, with the conserved type, T. alpinum (Linnaeus) Persoon, were presented (M. Salmenkallio and I. Kukkonen 1989), and the proposal was accepted in the Code. The proposal to segregate T. alpinum from the rest of Trichophorum, in the genus Eriophorella (J. Holub 1984), is based on characters that do not justify generic rank. In fact, K. Tan (1985) found that T. pumilum (Vahl) Schinz & Thellung could not be considered generically distinct from T. alpinum and created a combination for it within Eriophorella. The name Baeothryon Ehrhart ex A. Dietrich, previously considered to be a synonym of Trichophorum, has been shown to apply to a section of Eleocharis R. Brown (M. Salmenkallio and I. Kukkonen 1989; M. S. González-Elizondo and P. M. Peterson 1997).

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Key
1. Culms terete, smooth.
→ 2
1. Culms trigonous, angles scabrous.
→ 4
2. Achenes sharply trigonous; bracts 3.5–7.7 mm, exceeding spikes, apex with awn usually 1 mm or more.
T. clementis
2. Achenes compressed trigonous to plano-convex; bracts 1.6–4.5 mm, equaling or shorter than spikes, apex mucronate or awn less than 1 mm.
→ 3
3. Plants loosely cespitose, long-rhizomatous, slender; bracts to 2.5 mm, apex mucronate; perianth bristles absent; anthers 0.8–1.5 mm.
T. pumilum
3. Plants densely cespitose, not rhizomatous; bracts more than 3 mm, apex awned; perianth bristles 6; anthers 1.5–2.6 mm.
T. cespitosum
4. Flowers usually 15 or more per spike; perianth bristles white, flattened, to 20 times longer than achenes, smooth.
T. alpinum
4. Flowers fewer than 10 per spike; perianth bristles white to brown, terete, equaling or shorter than achenes, scabrous.
→ 5
5. Scales with obtuse apex, midribs not reaching apices in distal scales; leaves equaling or shorter than culms, 0.5–0.8(–1) mm wide.
T. clintonii
5. Scales (most or all) with mucronate apex, midribs excurrent; leaves equaling or exceeding culms, 0.8–2 mm wide.
T. planifolium
Source FNA vol. 23, p. 29. FNA vol. 23, p. 28. Author: William J. Crins.
Parent taxa Cyperaceae > Trichophorum Cyperaceae
Sibling taxa
T. alpinum, T. clementis, T. clintonii, T. planifolium, T. pumilum
Subordinate taxa
T. alpinum, T. cespitosum, T. clementis, T. clintonii, T. planifolium, T. pumilum
Synonyms Scirpus cespitosus, Baeothryon cespitosum, Scirpus bracteatus, Scirpus cespitosus var. callosus, Scirpus cespitosus var. delicatulus Eriophorella
Name authority (Linnaeus) Schur: Verh. Mitth. Siebenbürg. Vereins Naturwiss. Hermannstadt 4: 78. (1853) Persoon: Syn. Pl. 1: 69. (1805)
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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