Directory       News       Site Map       Home
    Jepson eFlora
Key to families | Table of families and genera



Perennial herb, erect, 50–200 cm, rhizomed, tubers durable. Stem: simple, sharply 3-angled, glabrous or angles scabrous, evident internal air cavities 0, not hollow. Leaf: basal and cauline, 3-ranked; sheath closed, long; ligule 0; blade generally present, long, thin, flat, V-shaped near base, keeled abaxially, margin, keel ± scabrous. Inflorescence: 1, terminal, panicle- (or head-) like, appearing with leaves; branches often scabrous; inflorescence bracts like leaf blades, main 1 > inflorescence; spikelets ± ovate, not ± flat, flower bracts spiraled, >= 25, each with 1 flower in axil, ± ovate, membranous to papery, puberulent (glabrous in age), brown to ± colorless, tip notched 0.5–1 mm, generally with curved awn often broken off. Flower: bisexual; perianth of 3–6 bristles, <= fruit, ± straight, stout, barbed; stamens 3, anthers >= 1.5 mm; style 1, thread-like, base not enlarged; stigmas 2–3. Fruit: generally obovate, smooth, brown, mucronate; wall cells small, solid or large, hollow (under dissecting microscope).
Wetlands, often emergent.
7–15 species: temperate, subtropics. (Greek: bulb rush, for tubers) [Browning et al. 1995 Brittonia 47:433–445; Smith 2002 FNANM 23:37–44] Intermediates (putative hybrids) between species cause major problems in classification, identification.
Unabridged etymology: (Greek, bolbos, a bulb, and schoenos a rush, reed, in reference to the tubers)
Unabridged note: Fruit wall anatomy (± easily seen with a dissecting microscope in a hand-made section) including diagnostic characters that are correlated with fruit buoyancy and persistence of bristles on shed fruit. Putative interspecific hybridization causes major taxonomic confusion; putative hybrids generally occur with their parents, are intermediate between them in all characters, often bear apparently normal fruit that vary in shape within one spikelet, and form persistent clones.

Key to Bolboschoenus

1. Stigmas 2; fruit 2-sided, tightly attached bristles 0 ..... B. maritimus subsp. paludosus

1' Stigmas generally 3; fruit generally 3-sided, tightly attached bristles 0–6

2. Flower bract awn base ± 0.5 mm wide; anthers orange; fruit floating on water, tightly attached bristles 0 ..... B. robustus

2' Flower bract awn base 0.2–0.3 mm wide; anthers yellow; fruit sinking in water, tightly attached bristles 3–6

3. Widest leaf blade >= 7 mm wide; spikelet 6–10 mm wide; leaf sheath tip papery, veined; fruit 3.8–5.5 mm, as deep as wide, mucro 0.2–0.8 mm ..... B. fluviatilis

3' Widest leaf blade < 7 mm wide; spikelet 3–5 mm wide; leaf sheath tip with triangular, membranous, veinless area; fruit 2.5–3.3 mm, shallower than wide, mucro <= 0.1 mm ..... B. glaucus

