Mosdenia Stent
Name referring to geography (Mosdene, Transvaal).
Habit, vegetative morphology. Perennial; stoloniferous (the stolons with densely imbricate cataphylls). Culms 10–90 cm high; herbaceous; unbranched above. Culm internodes solid. Plants unarmed. Young shoots intravaginal. Leaves mostly basal (those on the culms with reduced blades), or not basally aggregated; non-auriculate. Leaf blades linear to linear-lanceolate; narrow; to 5 mm wide (and to 12 cm long); without abaxial multicellular glands; without cross venation; persistent; ligule present; an unfringed membrane (laciniate); 0.3–0.5 mm long.
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 (those at the tip of the inflorescence sometimes reduced).
Inflorescence. Inflorescence a single spike (a dense, continuous, elongated bottlebrush, the spikelets spreading at right angles to the axis); espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets solitary; not secund; not two-ranked (in whorls or spirals); sessile, or subsessile (‘on minutely tomentose notches’); imbricate.
Female-fertile spikelets. Spikelets 2.5–3.75 mm long (sub-falcate); falling with the glumes; with conventional internode spacings. Rachilla terminated by a female-fertile floret. Hairy callus present. Callus short; blunt.
Glumes two; more or less equal (the G1 slightly longer and broader); about equalling the spikelets (or somewhat longer); long relative to the adjacent lemmas (exceeding them); lateral to the rachis; hairless (glabrous save at callus); pointed; awnless; carinate (G1), or non-carinate; very dissimilar (the G2 narrower, flat-backed). Lower glume about equalling the lowest lemma (slightly exceeding it); 1 nerved. Upper glume 1 nerved. Spikelets with female-fertile florets only; without proximal incomplete florets.
Female-fertile florets 1. Lemmas small, ovate-lanceolate; less firm than the glumes; delicate, hyaline; entire; pointed; awnless; hairless; carinate; without a germination flap; 1 nerved, or 3 nerved. Palea present; relatively long; apically notched (minutely); awnless, without apical setae; textured like the lemma (delicate, hyaline); not indurated; 2-nerved; 2-keeled. Lodicules present; 2; free; fleshy; glabrous. Stamens 3. Anthers 1.3–1.5 mm long; not penicillate; without an apically prolonged connective. Ovary glabrous. Styles free to their bases. Stigmas 2; red pigmented (purple), or brown.
Fruit, embryo and seedling. Fruit free from both lemma and palea; small (about 1.5 mm long); ellipsoid; longitudinally grooved; compressed dorsiventrally (dorsally). Hilum short (elliptical). Pericarp fused. Embryo large (about 1/3 the length of the fruit).
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells markedly different in shape costally and intercostally (the costals more regularly narrow). Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs present; chloridoid-type. Stomata common. Subsidiaries low dome-shaped. Intercostal short-cells absent or very rare (few). Costal short-cells conspicuously in long rows. Costal silica bodies present in alternate cell files of the costal zones; ‘panicoid-type’; cross shaped (to rectangular, near the leaf margins), or dumb-bell shaped (elsewhere); not sharp-pointed.
Transverse section of leaf blade, physiology. 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 with radiate chlorenchyma; traversed by columns of colourless mesophyll cells (seemingly, in places), or not traversed by colourless columns (but the bulliform-plus-colourless cell groups very deeply penetrating). Leaf blade ‘nodular’ in section to adaxially flat. Midrib not readily distinguishable; with one bundle only. Bulliforms present in discrete, regular adaxial groups; in simple fans and associated with colourless mesophyll cells to form deeply-penetrating fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present (with all the bundles); forming ‘figures’ (most bundles with rectangular adaxial and winged-crescentic abaxial girders).
Cytology. 2n = 40.
Taxonomy. Chloridoideae; main chloridoid assemblage.
Distribution, ecology, phytogeography. 1 species; South Africa. Mesophytic; species of open habitats; glycophytic. Dry savanna.
Paleotropical. African. Sudano-Angolan. South Tropical African.
References, etc. Morphological/taxonomic: Stent 1922. Leaf anatomical: photos of M. leptostachys provided by R.P. Ellis.
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).
