Herbs, perennial or less often annual, cespitose or not, rhizomatous, stoloniferous, rarely tuberous. Culms solitary or not, trigonous or round, glabrous or scabridulous with extrorse or antrorse (rarely retrorse) prickles. Leaves usually basal; ligules absent; blades keeled abaxially, flat, V-, or inversely W-shaped in cross section. Inflorescences terminal, rarely pseudolateral, 1st order subumbellate to capitate, 2d order with spicate or digitately arranged spikelets, rarely a solitary spikelet; spikelets 1-150; 1st order rays unequal (rarely equal) in length, produced singly from the axils of inflorescence bracts; involucral bracts 1-22, spirally arranged at culm apex, spreading to erect, leaflike. Spikelets: scales to 76, distichous, each subtending flower, cylindric to compressed, borne spicately or digitately at ends of rays (occasionally proliferous). Flowers bisexual [rarely unisexual], in axils of distichous floral scales, bases often decurrent onto rachilla as ± hyaline wings; perianth absent; stamens 1-3; styles linear, 2-3-fid, base deciduous or persistent; stigmas 2-3. Achenes biconvex, flattened, or trigonous.
Herbs, annual or perennial, cespitose or not, rhizomatous or not. Culms solitary or not, trigonous. Leaves basal; ligules absent; blades flat or V-shaped in cross section. Inflorescences terminal, rarely pseudolateral, spikes 1-4, sessile, densely ovoid or cylindric; spikelets [15-]40-150 per spike, not readily distinguished by unaided eye; involucral bracts 2-4, spreading or erect, leaflike. Spikelets: scales 2(-3), distichous; proximal scale subtending bisexual flower; distal scale empty or subtending 1-2 stamens, often abortive. Flowers bisexual or staminate; perianth absent; stamens 1-3; styles linear, 2-fid, base persistent. Achenes biconvex, laterally compressed. Tropical Africa contains the greatest diversity of Kyllinga species. The genus is closely related to Cyperus and has been treated as a subgenus.
Herbs, annual [rarely perennial], usually densely cespitose, not rhizomatous. Culms solitary or not, terete. Leaves basal, proximal bladeless or with involute appendage, distal with distinct blade, glabrous; ligules absent; blades setaceous to involute or flat. Inflorescences terminal, sometimes pseudolateral, ovoid clusters of spikes, spikes 1-4; spikelets [20-]50-150 per spike; involucral bracts 1-4, spreading or erect, leaflike. Spikelets: scales (1-)3, spirally arranged, 1 scale subtending flower, others empty. Flowers bisexual; perianth scales 1-2; stamens 1-2; styles linear, 2-3-fid, base deciduous or persistent, thickened or not. Achenes trigonous or terete. The morphology of the inflorescence has received various interpretations. One suggested that the inner transparent scale represents five perianth members that correspond to the bristles subtending the achenes in some species of Scirpus (S. Friedland 1941). Another proposed that Lipocarpha is a highly reduced derivative of a Cyperus-like ancestor (J. Raynal 1967); that view was accepted by G. C. Tucker (1987) and P. Goetghebeur and A. Van den Borre (1989). The shared feature of Kranz anatomy of the 'Cyperus type' further strengthens Raynal´s proposal. The achene and subtending scales of Lipocarpha are thus homologous to a single spikelet of Kyllinga or Cyperus. The interpretation of the secondary scales of Lipocarpha (Hemicarpha) as reduced scales of a spikelet (J. Raynal 1967) appears more plausible than the view of the secondary scale as fused perianth members (S. Friedland 1941). Lipocarpha drummondii and L. aristulata have been frequently confused and misidentified as each other or as L. micrantha. Reports of those species, or their synonyms, should be confirmed by examining supporting specimens. Lipocarpha squarrosa (Linnaeus) Goetghebeur, a native of southern Asia, is known as an adventive from the Gulf Coast of Florida; it is not included in the species count. It has subtrigonous achenes and three stigmas, and it would seem to key to L. maculata in the following key; however, it is a smaller plant, at most 20 cm tall, with anthers only 0.15-0.2 mm and achenes 0.4-0.55 mm.
Herbs, perennial, not cespitose, rhizomatous. Culms solitary, trigonous, 12 cm or less, smooth. Leaves cauline; sheaths present; ligules absent; blades flat to V-shaped in cross section, prominently keeled on abaxial surface. Inflorescences terminal, capitate; spikes 1-6; spikelets 100+; involucral bracts 1-6, spreading to suberect, leaflike. Spikelets: subtending bract 1, prophyll 1, scales 2, proximal scale empty, other scale subtending flower. Flowers bisexual; perianth absent; stamens 3; styles terete, 3-fid, base persistent. Achenes rounded-trigonous. Remirea has been included in Cyperus (J. H. Kern 1974; G. C. Tucker 1987, among others). In cladistic analyses (J. J. Bruhl 1995), Remirea almost always appeared as the sister group to the African monotypic Sphaerocyperus Lye and was directly grouped with neither the subgenera of Cyperus nor the narrowly defined genera segregated from Cyperus. Remirea is distinctive in possessing, among other features, thick, corky fertile internodes at maturity (which may be mistaken for the achene), rachillas of definite growth, leaf vascular bundles in multiple rows, culm epidermal cells radially elongated in transverse section, terminal spikelets present, C4 photosynthetic pathway, two fertile floral bracts, inflorescence prophylls not pulvinate, culms with hypodermis, and floral bracts persistent (J. J. Bruhl and S. Perry 1995). The structure of chloroplasts in vascular bundles differs from other C4 genera of Cyperaceae (M. M. Estelita 1993).
Scales distichous, the lowermost one empty and ±modified; fls perfect, each in the axil of a scale; perianth wanting; stamens 3, less often 1 or 2; style 2-3- cleft, the beakless (or nearly beakless) achene accordingly lenticular or ±trigonous; spikelets few-many in dense or loose spikes or heads, each subtended by 2 small bracts; spikes or heads commonly in a simple or compound terminal umbel that is subtended by sheathless, leafy invol bracts; each ray of the umbel surrounded at base by a tubular prophyll; herbs with solid, ±triangular stems, the lvs with closed sheath and usually an elongate, grasslike blade. 600+, cosmop. Our spp. belong to 5 subgenera, as in the following key. Spp. 14-22 and 23-28 appear to be intergradient, presumably reflecting extensive hybridization.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Scales spirally imbricate, ±scarious; fls perfect, each in the axil of a scale and subtended also by a very thin adaxial inner scale, or the inner scale often reduced or obsolete; stamen 1(2); style bifid; achene lenticular or subterete, minutely apiculate; delicate, glabrous annuals with few and slender lvs; spikes solitary to several, subsessile in a terminal head subtended by 2-3 unequal foliaceous bracts, the lowest of which appears like a continuation of the stem. ±5, mainly trop. Genus perhaps better submerged in Lipocarpha.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Scales spirally imbricate, ±scarious; fls perfect, each in the axil of a scale and also subtended by an additional pair of hyaline scales, one adaxial and persistent on the rachilla, the other abaxial and deciduous with the achene; stamens 1 or 2; style bifid or trifid; achene subtrigonous or lenticular; infl a terminal head of 3-several spikelets subtended by 2 or 3 foliaceous bracts. ±12, mainly trop.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.