Afrotrichloris Chiov.
Habit, vegetative morphology. Perennial; caespitose. Culms 30–60 cm high; herbaceous; unbranched above. Plants unarmed. Leaf blades narrow; about 1.5 mm wide (to 25 cm long); rolled; without abaxial multicellular glands; without cross venation; scarious, long pilose.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence a single spike (14–22 cm long, curved or flexuous). Inflorescence with axes ending in spikelets (?). Spikelet-bearing axes persistent.
Female-fertile spikelets. Spikelets 15 mm long; disarticulating above the glumes. Rachilla prolonged beyond the uppermost female-fertile floret; the rachilla extension with incomplete florets. Hairy callus present (?).
Glumes two; very unequal to more or less equal; (the upper) long relative to the adjacent lemmas; free; hairless; pointed; awnless (but acuminate); similar (divergent, narrowly lanceolate, hyaline). Lower glume 3–5 nerved. Upper glume 3–5 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets several, clustered; awned (male or sterile, and lacking the palea). Spikelets without proximal incomplete florets.
Female-fertile florets 1. Lemmas broadly rounded, thinly leathery below, with hyaline lobes; not becoming indurated; incised; 2 lobed; deeply cleft (to below the middle); awned. Awns 1, or 3; median, or median and lateral; the median similar in form to the laterals; from a sinus; non-geniculate; hairy; much longer than the body of the lemma. Lemmas hairy. The hairs in tufts (on the lateral nerves, the lobes glabrous), or not in tufts; not in transverse rows. Lemmas non-carinate (rounded on the back); 3 nerved. Palea present; relatively long; awnless, without apical setae; 2-nerved; 2-keeled. Lodicules present; 2; free; glabrous. Stamens 3. Anthers not penicillate; without an apically prolonged connective. Ovary glabrous. Styles free to their bases. Stigmas 2.
Fruit, embryo and seedling. Fruit small (2 mm long); ellipsoid (oblong-elliptical); compressed dorsiventrally. Pericarp free.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae present; intercostal. Intercostal papillae over-arching the stomata; consisting of one oblique swelling per cell to consisting of one symmetrical projection per cell (the papillae large relative to the cells carrying them). Long-cells differing markedly in wall thickness costally and intercostally (intercostals thicker-walled). Intercostal zones with typical long-cells (but these rather short). Mid-intercostal long-cells rectangular; not readily observable in detail, because of the abundant papillae. Microhairs present; more or less spherical to elongated; clearly two-celled; chloridoid-type. Microhair apical cell wall of similar thickness/rigidity to that of the basal cell. Microhair basal cells 15 microns long. Microhair total length/width at septum 2. Microhair apical cell/total length ratio 0.37. Stomata common. Subsidiaries non-papillate; seemingly all dome-shaped (but extensively obscured by papillae). Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells common; not paired (solitary); not silicified. Intercostal silica bodies absent. Costal short-cells conspicuously in long rows (but the short-cells rather long in some files). Costal silica bodies present in alternate cell files of the costal zones; exclusively saddle shaped (a rather round form of this type).
Transverse section of leaf blade, physiology. Lamina mid-zone in transverse section open.
C4; XyMS+. PCR sheaths of the primary vascular bundles interrupted; interrupted abaxially only and interrupted both abaxially and adaxially. PCR sheath extensions absent. Mesophyll with radiate chlorenchyma; traversed by columns of colourless mesophyll cells. Leaf blade with distinct, prominent adaxial ribs to ‘nodular’ in section. Midrib conspicuous (via a rather larger bundle, and its adaxial group of colourless cells); with one bundle only; with colourless mesophyll adaxially. Bulliforms present in discrete, regular adaxial groups; in simple fans, or associated with colourless mesophyll cells to form deeply-penetrating fans (these associated with colourless girders). All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present (with most bundles); forming ‘figures’ (in the large bundles). Sclerenchyma all associated with vascular bundles. The lamina margins with fibres.
Taxonomy. Chloridoideae; main chloridoid assemblage.
Distribution, ecology, phytogeography. 2 species; Somalia.
Paleotropical. African. Sudano-Angolan. Somalo-Ethiopian.
References, etc. Leaf anatomical: this project.
Special comments. Fruit data wanting.
Illustrations. • Abaxial epidermis of leaf blade. Afrotrichloris martinii.
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).
