Mniochloa Chase
From the Greek mnio (moss) and chloa (a grass), alluding to mosslikehabit.
Habit, vegetative morphology. Slender perennial (with dimorphic culms); caespitose. The flowering culms leafless (with 1–3 bladeless sheaths). Culms 10–25 cm high (the vegetative culms 3–12 cm tall, the flowering culms longer); herbaceous; unbranched above; tuberous. Rhizomes pachymorph. Plants unarmed. Young shoots intravaginal. Leaves not basally aggregated; without auricular setae. Leaf blades elliptic; narrow (but relatively broad); 3–5 mm wide (and 8–18 mm long); not cordate, not sagittate (base cuneate, no more than slightly asymmetric); flat; shortly pseudopetiolate; persistent; rolled in bud; an unfringed membrane, or a fringed membrane (?- ‘a hyaline, lacerate, ciliate membrane’); truncate; about 0.1 mm long.
Reproductive organization. Plants monoecious with all the fertile spikelets unisexual; without hermaphrodite florets. The spikelets of sexually distinct forms on the same plant; male-only and sterile. The male and female-fertile spikelets on different branches of the same inflorescence. The spikelets overtly heteromorphic.
Inflorescence. Inflorescence of spicate main branches (of two spike-like racemes, the one male, the somewhat longer one female); digitate. Primary inflorescence branches 2. Inflorescence espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes ‘racemes’; persistent. Spikelets solitary; secund (on one side of the slender, triquetrous rachis); pedicellate (with very short, clavate pedicels); not in distinct ‘long-and-short’ combinations.
Female-sterile spikelets. The male racemes slightly shorter; male spikelets 1.3--1.7 mm long, much shorter than females, ellipsoid, acute; lemma 1-nerved, palea 2-nerved, lemma and palea membranous; 3 free, non-penicillate stamens. Rachilla of male spikelets terminated by a male floret. The male spikelets without glumes; without proximal incomplete florets; 1 floreted. The lemmas awnless. Male florets 1; 3 staminate. The staminal filaments free.
Female-fertile spikelets. Spikelets 2–4.5 mm long; narrowly elliptic; compressed dorsiventrally; with conventional internode spacings (i.e. no stipe above the glumes). Rachilla terminated by a female-fertile floret. Hairy callus absent.
Glumes two; relatively large; very unequal to more or less equal (the lower somewhat shorter); shorter than the spikelets; shorter than the adjacent lemmas; hairless; pointed to not pointed; awnless; non-carinate; similar (delicately membranous, ovate-elliptical). Spikelets with female-fertile florets only.
Female-fertile florets 1. Lemmas similar in texture to the glumes, or decidedly firmer than the glumes (membranous); becoming indurated (white-cartilaginous); entire; pointed, or blunt; awnless (and not apiculate); hairless; glabrous; non-carinate; having the margins inrolled against the palea. Palea present; relatively long; entire; awnless, without apical setae (glabrous); textured like the lemma (which enfolds it); indurated. Lodicules present; 3. Stamens 0 (and no vestiges).
Fruit, embryo and seedling. Disseminule a free caryopsis. Fruit free from both lemma and palea; small (1.5–2 mm long); fusiform; longitudinally grooved; compressed dorsiventrally. Hilum long-linear. Embryo small.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae present; costal and intercostal. Intercostal papillae over-arching the stomata, or not over-arching the stomata; several per cell (small, numerous, and often forming rings around the stomata). Long-cells markedly different in shape costally and intercostally (the costals much narrower); of similar wall thickness costally and intercostally (thin walled). Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs present; elongated; clearly two-celled; panicoid-type; 36–46 microns long; 6.3–7.5 microns wide at the septum. Microhair total length/width at septum 9–10.2. Microhair apical cells 8–15 microns long. Microhair apical cell/total length ratio 0.2–0.4. Stomata common; 13–17 microns long. Subsidiaries non-papillate; parallel-sided. Guard-cells overlapped by the interstomatals (slightly). Intercostal short-cells absent or very rare. No macrohairs, but hooks and prickles common. Costal short-cells conspicuously in long rows. Costal silica bodies ‘panicoid-type’; predominantly short dumb-bell shaped.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with adaxial palisade; with arm cells; without fusoids. Leaf blade adaxially flat. Midrib conspicuous (by virtue of its large bundle and relatively massive ‘anchor’ of sclerenchyma); with one bundle only. The lamina symmetrical on either side of the midrib. Bulliforms present in discrete, regular adaxial groups; in simple fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’ (most bundles with an ‘anchor’). Sclerenchyma all associated with vascular bundles.
Taxonomy. Bambusoideae; Oryzodae; Olyreae.
Distribution, ecology, phytogeography. 1 species; Cuba. Mesophytic; shade species. On lowland limestone cliffs.
Neotropical. Caribbean.
References, etc. Morphological/taxonomic: Chase 1908; Zuloaga et al. 1993. Leaf anatomical: Zuloaga et al. 1993.
Special comments. Fruit data wanting.
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).