Leucophrys Rendle
Sometimes referred to Brachiaria sensu lato
Habit, vegetative morphology. Perennial. Culms 7–100 cm high; woody and persistent (stiffly geniculate); branched above (the plants bushy). Culm nodes glabrous. Culm internodes solid. Young shoots intravaginal. Leaves not basally aggregated; non-auriculate. Leaf blades linear-lanceolate; narrow; 2–4 mm wide; flat, or rolled; hard, woody, needle-like (sometimes spiny, hard and brittle), or not needle-like; without cross venation; disarticulating from the sheaths (leaving the culms as the main organs of photosynthesis); a fringe of hairs; 0.6–0.8 mm long. Contra-ligule absent.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence paniculate; contracted; espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets solitary, or paired; not secund; pedicellate (and substipitate, with a short stalk fitting into the pedicel apex). Pedicel apices cupuliform. Spikelets consistently in ‘long-and-short’ combinations, or not in distinct ‘long-and-short’ combinations.
Female-fertile spikelets. Spikelets 4–6 mm long; abaxial to adaxial (the orientation variable); compressed dorsiventrally; biconvex; falling with the glumes; not disarticulating between the florets; with conventional internode spacings. Rachilla terminated by a female-fertile floret. Hairy callus absent. Callus absent.
Glumes two; relatively large; very unequal to more or less equal; about equalling the spikelets to exceeding the spikelets; (the longer) long relative to the adjacent lemmas; hairy; with distinct rows of hairs (the upper with a transverse row above the middle, the lower glabrous save at the base); pointed (the tips minutely truncate); awnless (but the tips caudate, inrolled, membranous); non-carinate; very dissimilar (the lower obtuse or notched at the apex, pilose at the base, the upper tapering, caudate, dorsally long-villous with a transverse fringe just above the middle). Lower glume 0.75–1 times the length of the upper glume; about equalling the lowest lemma; 3 nerved. Upper glume 5–7 nerved. Spikelets with incomplete florets. The incomplete florets proximal to the female-fertile florets. Spikelets with proximal incomplete florets. The proximal incomplete florets 1; paleate. Palea of the proximal incomplete florets fully developed; not becoming conspicuously hardened and enlarged laterally. The proximal incomplete florets male. The proximal lemmas awnless (the tip inrolled, membranous, sometimes slightly caudate, the back with a transverse fringe of hairs); 3 nerved; decidedly exceeding the female-fertile lemmas (about twice as long); less firm than the female-fertile lemmas; not becoming indurated.
Female-fertile florets 1. Lemmas decidedly firmer than the glumes; smooth; becoming indurated (glossy); entire; pointed, or blunt; awnless; hairless; glabrous; non-carinate; having the margins inrolled against the palea; with a clear germination flap (basal); 5 nerved. Palea present; relatively long; tightly clasped by the lemma; entire; awnless, without apical setae; textured like the lemma; indurated; 2-nerved; 2-keeled. Palea keels glabrous. Lodicules present; 2; free; fleshy; glabrous; not or scarcely vascularized. Stamens 3. Anthers 2–2.5 mm long; not penicillate; without an apically prolonged connective. Ovary glabrous. Styles free to their bases. Stigmas 2.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells markedly different in shape costally and intercostally (the costals relatively longer and narrower). Intercostal zones with typical long-cells. Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs present; panicoid-type. Stomata common. Subsidiaries mostly dome-shaped. Intercostal short-cells common; seemingly not paired. With rosettes of isodiametric cells around each of the abundant macrohairs. Costal short-cells conspicuously in long rows. Costal silica bodies ‘panicoid-type’; not sharp-pointed.
Transverse section of leaf blade, physiology. C4; XyMS+. PCR sheath extensions absent. PCR cell chloroplasts centrifugal/peripheral. Mesophyll with radiate chlorenchyma. Leaf blade adaxially flat. Midrib not readily distinguishable; with one bundle only. Bulliforms present in discrete, regular adaxial groups (and also some rather irregular groups); in simple fans. Many of the smallest vascular bundles unaccompanied by sclerenchyma. Combined sclerenchyma girders present (with the major ones only); nowhere forming ‘figures’. Sclerenchyma all associated with vascular bundles.
Taxonomy. Panicoideae; Panicodae; Paniceae.
Distribution, ecology, phytogeography. 1 species; tropical and southern Africa. Helophytic, or xerophytic; species of open habitats; glycophytic. Sandy riverbeds in semidesert.
Paleotropical. African. Namib-Karoo.
References, etc. Morphological/taxonomic: Rendle 1922; Launert 1970. Leaf anatomical: photos of L. mesocoma provided by R.P. Ellis.
Special comments. Fruit data wanting.
Illustrations. • General aspect
Cite this publication as: Watson, L., and Dallwitz, M. J. (1992 onwards). ‘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.’ http://biodiversity.uno.edu/delta/. Version: 18th August 1999. Dallwitz (1980), Dallwitz, Paine and Zurcher (1993 onwards, 1998), and Watson and Dallwitz (1994), and Watson, Dallwitz, and Johnston (1986) should also be cited (see References).
