Monographs Details:
Authority:
Maguire, Bassett. 1967. The botany of the Guayana Highland--Part VII. Mem. New York Bot. Gard. 17: 1-439.
Maguire, Bassett. 1967. The botany of the Guayana Highland--Part VII. Mem. New York Bot. Gard. 17: 1-439.
Family:
Cyperaceae
Cyperaceae
Description:
Genus Description - Spikes compound, generally ellipsoid, with numerous imbricated glumes, each subtending an axillary spikelet; spikelets consisting of 2 secondary glumes (squa-mellae), the squamellae lateral and opposite, folded with an acute keel, sometimes incompletely connate into a spathe-like or sac-like structure, the keel usually spinulose-hispid; a monandrous staminate flower borne at axil of both squamellae; pistillate flower a terminal naked pistil, the style slender, 2-cleft at apex (stigmas), the ovary developing into biconvex fructification, the utricle completely adnate to the contained achene. Perennials; leaves radical or nearly so, sometimes upper few on the culm; leaf blades linear, occasionally lanceolate or oblong, more or less 3-costate (rarely lateral costas superficially indistinct); culms central or lateral, the lateral ones frequently clothed at base with bladeless sheaths or cataphylls; inflorescence a terminal umbel-like corymb, a panicle or sometimes congested in a head, with leafy involucre.
Distribution and Ecology - About 50 species in the tropical regions of both hemispheres. The genus Hypolytrum is best represented in Brazil as far as the known South American plants are concerned. However, no comprehensive collection of Hypolytrum species has ever been made in Brazil, and therefore, most of the species so far described are known only by the type collections. A systematic revision of all South American species cannot be made until these Brazilian taxa are critically studied. The following is an annotated enumeration of the Guayanan species of Hypolytrum that I recognize to be valid.
Genus Description - Spikes compound, generally ellipsoid, with numerous imbricated glumes, each subtending an axillary spikelet; spikelets consisting of 2 secondary glumes (squa-mellae), the squamellae lateral and opposite, folded with an acute keel, sometimes incompletely connate into a spathe-like or sac-like structure, the keel usually spinulose-hispid; a monandrous staminate flower borne at axil of both squamellae; pistillate flower a terminal naked pistil, the style slender, 2-cleft at apex (stigmas), the ovary developing into biconvex fructification, the utricle completely adnate to the contained achene. Perennials; leaves radical or nearly so, sometimes upper few on the culm; leaf blades linear, occasionally lanceolate or oblong, more or less 3-costate (rarely lateral costas superficially indistinct); culms central or lateral, the lateral ones frequently clothed at base with bladeless sheaths or cataphylls; inflorescence a terminal umbel-like corymb, a panicle or sometimes congested in a head, with leafy involucre.
Distribution and Ecology - About 50 species in the tropical regions of both hemispheres. The genus Hypolytrum is best represented in Brazil as far as the known South American plants are concerned. However, no comprehensive collection of Hypolytrum species has ever been made in Brazil, and therefore, most of the species so far described are known only by the type collections. A systematic revision of all South American species cannot be made until these Brazilian taxa are critically studied. The following is an annotated enumeration of the Guayanan species of Hypolytrum that I recognize to be valid.
Discussion:
Type. Hypolytrum latifolium L. C. Richard [ =H. nemorum (Vahl) Sprengel].