Habrochloa C.E. Hubb.
Habit, vegetative morphology. Slender annual. Culms 5–50 cm high; herbaceous; unbranched above. Leaves not basally aggregated; non-auriculate. Leaf blades narrow; 2–2.5 mm wide (and 1–8 cm long); flat; without cross venation; a fringe of hairs.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets; exposed-cleistogamous.
Inflorescence. Inflorescence paniculate; delicate, open; with capillary branchlets; non-digitate; espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund.
Female-fertile spikelets. Spikelets 2–2.5 mm long; compressed laterally; disarticulating above the glumes; disarticulating between the florets; with conventional internode spacings. Rachilla prolonged beyond the uppermost female-fertile floret; hairless; the rachilla extension with incomplete florets. Hairy callus present (small). Callus short.
Glumes two; relatively large; more or less equal (the G2 slightly shorter); shorter than the spikelets to about equalling the spikelets; long relative to the adjacent lemmas (exceeding them); hairless; pointed (acute to acuminate); awnless; carinate; similar (linear-lanceolate, hyaline). Lower glume 1 nerved. Upper glume 1 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets merely underdeveloped. Spikelets without proximal incomplete florets.
Female-fertile florets 2–5. Lemmas similar in texture to the glumes to decidedly firmer than the glumes (thinly membranous, translucent); not becoming indurated; incised; very shortly 2 lobed (the lobes themselves obtuse or minutely bidentate); not deeply cleft; awned. Awns 1; median; from a sinus; non-geniculate; gently recurving, or flexuous; hairless (scabrid); much longer than the body of the lemma (to about 7 mm long, very slender). Lemmas hairy; carinate; 3 nerved. Palea present; relatively long; entire to apically notched; awnless, without apical setae; not indurated (thinly membranous); 2-nerved; 2-keeled. Lodicules present; 2; free; fleshy; glabrous. Stamens 3. Anthers 0.1–0.3 mm long; not penicillate; without an apically prolonged connective. Ovary glabrous. Styles free to their bases. Stigmas 2.
Fruit, embryo and seedling. Fruit small (0.8–1 mm long); linear, or ellipsoid; trigonous. Hilum short. Embryo small (about 1/4 of the fruit length).
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Mid-intercostal long-cells rectangular and fusiform; having markedly sinuous walls (but the sinuations gentle). Microhairs present; panicoid-type (the apical cells all missing in material seen); 30(–37.5) microns long; 5.4 microns wide at the septum. Microhair total length/width at septum 5.56–6.94. Microhair apical cells 16.5–21 microns long. Microhair apical cell/total length ratio 0.55–0.6. Stomata absent or very rare (though surprisingly so, in this relatively thin-walled epidermis); 21–22.5 microns long. Intercostal short-cells absent or very rare (none seen). Costal short-cells conspicuously in long rows (though some files have relatively long short-cells). Costal silica bodies ‘panicoid-type’; more or less exclusively dumb-bell shaped (large).
Transverse section of leaf blade, physiology. Almost certainly C3 (though the material seen poor); XyMS+. Leaf blade adaxially flat. Midrib not readily distinguishable; with one bundle only. Bulliforms not present in discrete, regular adaxial groups. Combined sclerenchyma girders present; forming ‘figures’ (small anchors in the primaries only, the other bundles depauperate in sclerenchyma). Sclerenchyma all associated with vascular bundles.
Taxonomy. Arundinoideae; Danthonieae.
Distribution, ecology, phytogeography. 1 species; East tropical Africa. Shade species; glycophytic. On slopes.
Paleotropical. African. Sudano-Angolan. South Tropical African.
References, etc. Morphological/taxonomic: Hubbard 1967a. Leaf anatomical: this project.
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).