Entry From
Flora of Tropical Africa, Vol 10, page 1, (1937) Author: (By C. E. HUBBARD.)
Information
Spikelets linear to narrowly lanceolate or narrowly oblong, often acuminate, usually large, paired or solitary, rarely in threes, pedicelled in open or contracted, rarely spike-like, panicles; rhachilla glabrous, readily disarticulating between the florets and less readily or continuous between the upper glume and lower floret, not or very rarely produced beyond the upper floret. Florets 2, heteromorphous; lower ♂ or rarely barren or reduced to the valve; upper hermaphrodite, smaller than the lower. Glumes persistent, unequal, chartaceous to coriaceous, 3- (rarely 5-) nerved, glabrous, or bristly from black or brown tubercles; lower narrowly lanceolate to broadly ovate or ovate-elliptic, acute, acuminate, obtuse or truncate, rarely setaceously acuminate, one-fourth to three-fourths the length of the spikelet; upper linear-lanceolate to lanceolate, obtuse or truncate, less often acute and rarely setaceously acuminate, as long or nearly as long as the spikelet. Lower floret: valve somewhat similar to the upper glume, glabrous or sparingly hairy, 3- (rarely 5–7-) nerved; valvule linear to linear-lanceolate, shorter than the valve, 2-keeled, membranous. Upper floret linear to linear-lanceolate, terete, with a slender pungent, 2-toothed, emarginate or truncate bearded callus: valve at length thinly coriaceous or coriaceous, pilose, pubescent to glabrescent, 5–9-nerved, shortly 2-lobed, rarely entire, with the lobes obtuse or acute, awned from between the two lobes or from the tip; awn geniculate, twisted below the bend; valvule linear, as long as the valve, 2-keeled, channelled between the keels, with the latter thickened, approximate and tightly embraced by the involute margins of the valve. Lodicules 2, linear or narrowly cuneate. Stamens 2 or rarely 3; anthers linear. Ovary glabrous; styles free, terminal; stigmas plumose, laterally exserted. Grain linear to oblong, terete or with a shallow longitudinal groove, tightly embraced by the valve and valvule; embryo large; hilum linear. —Perennials or rarely annuals; culms mostly erect, slender to robust, simple or rarely branched, 1–5-noded; leaf-blades narrowly linear to linear, flat or convolute, rigid; ligule reduced to a hairy rim; spikelets 2 1/2–18 lin. long, yellowish- to reddish-brown or dark brown.
Range
Species about 40, mainly in tropical Africa, extending into South Africa and Madagascar, 1 in tropical South America.
Notes
The genus Loudetia, Hochst. was first proposed by Hochstetter for an Abyssinian grass, L. elegans. This name appeared on printed labels with the specimens, and also in a list in Flora, xxiv. I. Intell. 20 (1841), but in each case it was unaccompanied by a description. A. Braun (l.c. xxiv. II. 713: 1841) considered that the differences between Loudetia and Tristachya were insufficient to retain them as distinct genera and he adopted the former generic name, including the earlier Tristachya Nees as a section under it. The name Loudetia Hochst. ex A. Br., thus being superfluous, was illegitimate. The valid publication of the generic name Loudetia dates from Steudel (Syn. Pl. Glum. i. 238: 1854), who supplied a generic description (excluding Tristachya Nees). The name Loudetia as used by him is not a later homonym, since it is based on the same type as the illegitimately applied name Loudetia A. Br.The differences between Trichopteryx, Nees, and Loudetia, Hochst. ex Steud. are given under the former genus (p. 4). Loudetia is, however, more closely related to Tristachya, Nees, and in some cases the characters separating them are very few, but the majority of its species (all those of sect. Eu-Loudetia) are readily distinguished by the paired or solitary spikelets. The species of the sect. Pseudotristachya have the spikelets pedicelled in clusters of three, but the spikelets agree in general structure with those of sect. Eu-Loudetia. It is in sect. Paratristachya that a close connection exists with the genus Tristachya. The spikelets in this section are solitary, paired or in threes, and in the latter case they only differ from Tristachya by their broader and shorter lower glume which is ovate to elliptic-ovate or oblong when flattened and from one-third to half the length of the spikelet.