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The grass genera of the world

L. Watson, T.D. Macfarlane, and M.J. Dallwitz

Baptorhachis Clayton & Renvoize

~ Stereochlaena (S. foliacea)

Habit, vegetative morphology. Annual. Culms 30–60 cm high; herbaceous; unbranched above. Culm nodes glabrous. Culm internodes hollow. Leaves not basally aggregated; auriculate. Leaf blades linear-lanceolate; narrow; 2–4 mm wide (and 2–5 cm long); flat; not pseudopetiolate; without cross venation; persistent. Ligule a fringed membrane; truncate; about 1 mm long. Contra-ligule absent.

Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets.

Inflorescence. Inflorescence a single raceme. Rachides conspicuously flattened and winged (the wing covering the spikelets, dark purple). Inflorescence espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes ‘racemes’; persistent. Spikelets paired; secund; biseriate; sessile and pedicellate, or subsessile and pedicellate; densely imbricate; consistently in ‘long-and-short’ combinations (but these homogamous). The ‘shorter’ spikelets hermaphrodite. The ‘longer’ spikelets hermaphrodite.

Female-fertile spikelets. Spikelets 2.5–3 mm long; abaxial; compressed dorsiventrally; biconvex; falling with the glumes; with conventional internode spacings. Rachilla terminated by a female-fertile floret. Hairy callus absent (but the long hairs on the glume and first lemma direct the resting position of the spikelet). Callus absent.

Glumes one per spikelet (the G1 suppressed); about equalling the spikelets (i.e. the G2); long relative to the adjacent lemmas (i.e. the G2 about equalling the L1); dorsiventral to the rachis; hairy; with distinct hair tufts (the lateral keels with hair tufts below); pointed; awned (from a sinus or from the tip); non-carinate. Upper glume 3 nerved (the two laterals thickenced below). Spikelets with incomplete florets. The incomplete florets proximal to the female-fertile florets. The proximal incomplete florets 1; epaleate; sterile. The proximal lemmas bilobed; awned (from the sinus); 5 nerved, or 7 nerved; more or less equalling the female-fertile lemmas; less firm than the female-fertile lemmas (membranous between the leathery lateral keels, which are hair-tufted below).

Female-fertile florets 1. Lemmas decidedly firmer than the glumes (papery); smooth (and shining); not becoming indurated; entire; pointed (acute); awnless; hairless; glabrous; non-carinate; having the margins lying flat on the palea; without a germination flap; 3 nerved. Palea present; relatively long; tightly clasped by the lemma; entire; awnless, without apical setae; textured like the lemma (papery); not indurated; 2-nerved. Lodicules absent. Stamens 3. Anthers about 0.7 mm long; without an apically prolonged connective. Ovary apically glabrous. Styles free to their bases. Stigmas 2; white.

Abaxial leaf blade epidermis. Microhairs present; panicoid-type.

Transverse section of leaf blade, physiology. C4; XyMS–. Leaf blade adaxially flat.

Special diagnostic feature. Spikelets borne on one side of a broad, leaflike rachis (this colourful).

Classification. Watson & Dallwitz (1994): Panicoideae; Panicodae; Paniceae. Soreng et al. (2015): Panicoideae; Panicodae; Paspaleae; Paspalinae. 1 species (S. foliacea).

Distribution, phytogeography, ecology. Mozambique.

Xerophytic; species of open habitats. On stony slopes.

References, etc. Morphological/taxonomic: Clayton 1978b.

Special comments. Fruit data wanting. Anatomical data wanting. Illustrations. • B. foliacea: Clayton, Flora Zambesiaca 10 (1989)

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, and classifications. See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Watson, L., Macfarlane, T.D., and Dallwitz, M.J. 1992 onwards. The grass genera of the world: descriptions, illustrations, identification, and information retrieval; including synonyms, morphology, anatomy, physiology, phytochemistry, cytology, classification, pathogens, world and local distribution, and references. Version: 11th December 2017.’.