Rendlia Chiov.
Sometimes referred to Microchloa
Habit, vegetative morphology. Perennial; densely caespitose (from a cushion of old, fibrous leaf sheaths). Culms 5–35 cm high; herbaceous; unbranched above. Culm nodes glabrous. Culm internodes solid. Plants unarmed. Young shoots intravaginal. Leaves mostly basal; non-auriculate. The basal sheaths persistent, densely woolly, fibrous when old. Leaf blades linear; narrow; to 0.7 mm wide; setaceous; folded (at the base, the adaxial surfaces adnate); without abaxial multicellular glands; without cross venation; persistent (but usually burned off annually); ligule present; a fringed membrane (the ‘membrane’ unusually firm); 0.2–0.3 mm long. Contra-ligule absent.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets. The spikelets of sexually distinct forms on the same plant, or all alike in sexuality; hermaphrodite, or hermaphrodite and sterile (the uppermost 2–3 spikelets reduced).
Inflorescence. Inflorescence a single spike (to 5 cm long, rarely a pair of spikes). Inflorescence axes not ending in spikelets (their tips obtuse). Rachides flattened and winged (convex on back, with membranous, hairy margins). Inflorescence espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes spikes; persistent. Spikelets solitary; secund; alternately biseriate; sessile; imbricate.
Female-fertile spikelets. Spikelets 4–5.5 mm long; adaxial; with the G1 compressed obliquely, the G2 compressed dorsiventrally; disarticulating between the glumes (disarticulating above the persistent G1, the G2 falling with and enveloping the florets); not 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; pointed.
Glumes two; more or less equal; exceeding the spikelets; long relative to the adjacent lemmas (both longer than the florets); lateral to the rachis; hairy (lanose, G2), or hairless (glabrous, G1); without conspicuous tufts or rows of hairs; obtuse, lanceolate-oblong; awnless; carinate (G1), or non-carinate (G2); very dissimilar (firmly membranous, the G1 obliquely laterally compressed, the G2 dorsally compressed). 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 1; male or sterile, banana-shaped, hairless, the lemma shorter and thinner than the L1, the palea reduced or absent; awnless.
Female-fertile florets 1. Lemmas similar in texture to the glumes; not becoming indurated; incised; shortly 2 lobed; not deeply cleft; awnless; hairy (with dense, silky hairs on the keels); non-carinate (but rather, 3 keeled: laterally compressed, the margins beyond the lateral keels narrow, hyaline, infolded); without a germination flap; 3 nerved. Palea present; relatively long (slightly exceeding the lemma); apically notched; awnless, without apical setae (glabrous); thinner than the lemma; not indurated (hyaline-membranous); 2-nerved; 2-keeled. Palea keels wingless; minutely scabrous. Lodicules present (briefly joined to the base of the palea); 2; free; fleshy; glabrous. Stamens 3. Anthers 2.5 mm long; not penicillate; without an apically prolonged connective. Ovary glabrous (suppressed in the upper floret). Styles free to their bases. Stigmas 2; brown.
Fruit, embryo and seedling. Fruit free from both lemma and palea; small (2 mm long); ellipsoid; compressed dorsiventrally, or trigonous. Hilum short. Embryo small (seemingly, judging from immature material).
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells of similar wall thickness costally and intercostally (medium thick walled). Mid-intercostal long-cells rectangular; having markedly sinuous walls (and pitted). Microhairs present; more or less spherical; ostensibly one-celled (15 to 18 microns in diameter); chloridoid-type. Stomata common; 27–28.5–30 microns long. Subsidiaries high dome-shaped, or triangular. 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. Costal silica bodies confined to the central file(s) of the costal zones; almost exclusively saddle shaped (large); not sharp-pointed.
Transverse section of leaf blade, physiology. Leaf blades consisting of midrib (there being only a flange of lamina and two bundles on each side, these increasingly reduced acropetally). Lamina mid-zone in transverse section open.
C4; XyMS+. PCR sheaths of the primary vascular bundles interrupted; interrupted both abaxially and adaxially. PCR sheath extensions absent. PCR cell chloroplasts centripetal. Mesophyll without arm cells (although with some hints of wall intrusions in the material seen). Midrib having a conventional arc of bundles (a large arc of about 16 bundles, with the median slightly larger than the rest); with colourless mesophyll adaxially (the entire adaxial area of the leaf being ‘colourless’). All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present (with the large lamina-flange bundles only); forming ‘figures’ (the lamina-flange bundles only). Sclerenchyma all associated with vascular bundles. The lamina margins with fibres.
Taxonomy. Chloridoideae; main chloridoid assemblage.
Distribution, ecology, phytogeography. 1 species; eastern tropical and southern Africa. Mesophytic; species of open habitats; glycophytic. Shallow soils in grasslands.
Paleotropical. African. Sudano-Angolan. South Tropical African.
References, etc. Leaf anatomical: this project.
Illustrations. • General aspect. • Abaxial epidermis of leaf blade. • Transverse section of leaf blade
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).
