Family: Poaceae |
Mary E. Barkworth Plants annual or perennial; cespitose. Culms 20-200 cm, simple or branched. Leaves sometimes aromatic and smelling of lemon oil or citronella; sheaths keeled, sometimes with a row of glandular depressions on the keel; ligules membranous, glabrous or ciliate. Inflorescences terminal and axillary; peduncles usually with 1 rame, sometimes with several in a digitate cluster; rames with 3-10 homogamous, unawned, sessile-pedicellate spikelet pairs on the lower 1/4-2/3 and heterogamous, awned, sessile-pedicellate spikelet pairs distally, axes slender, without a translucent median groove; disarticulation in the rames, beneath the sessile spikelets of the heterogamous spikelet pairs, sometimes also below their pedicellate spikelets. Homogamous spikelet units sterile or staminate; callusespoorly developed; glumes membranous, many-veined, keels winged above. Heterogamous spikelet units: sessile spikelets bisexual, terete; calluses 1.5-3 mm, sharp, antrorsely strigose, hairs golden brown; glumes coriaceous, pubescent, concealing the florets; lower glumes enclosing the upper glumes, obscurely 5-9-veined; upper glumes sulcate, 3-veined; lower florets sterile, reduced to a hyaline lemma; upper florets bisexual, lemmas with conspicuous, geniculate awns; awns 5-15 cm, with hairs. Caryopses lanceolate, sulcate on 1 side. Pedicels short, free of the rame axes, not grooved; pedicellate spikelets sterile or staminate, larger than the sessile spikelets; calluses long, glabrous, functioning as pedicels; glumes membranous, many-veined, keels winged above. x = 10, 11. Name from the Greek heteros, different, and pogon, beard, alluding to the difference between the calluses of the spikelets in the heterogamous pairs. T.A. Cope (1995) Heteropogon. Flora of Somalia 4: Plants annual or perennial. Leaves: ligules short, membranous, upper edges ciliate. Inflorescences composed of rames, spikelike inflorescence units composed of sessile-pedicellate pairs of spikelets, these terminal or axillary, either single or in clusters, sometimes loosely aggregated into panicle-like inflorescences; rames with homogamous spikelet apirs in the loawer 1/4-2/3; internodes linear. Sessile spikelets subterete; calluses long, pointed; lower glumes coriaceous, convex, obtuse; lower florets reduced to hylaline membrans; upper florets stipelike, passing directly into a stout, pubescent, awn. Pedicellate spikelets male or sterile, lanceolate, larger than the sessile, unawned; calluses long, slender, functioning as pedicels, the true pedicels reduced to tiny stumps. Caryopses lanceolate, channeled on one side. Heteropogon includes four species. They grow in tropical and warm temperate regions throughout the world. One species, Heteropogon contortus, is known from both Somaliland and Somalia. Global distribution of Heterpogon. Note: GBIF records include introduced and cultivated plants. Consequently, the distribution shown often differs from statements about a taxon's native distribution. |