The grass genera of the world
Including Pollinidium Haines
Habit, vegetative morphology. Perennial; caespitose. Culms 40–100 cm high; herbaceous (with thickened, woolly rootstock); unbranched above. Leaf blades linear; narrow (long, rigid); 2–3 mm wide; folded, or rolled; without cross venation. Ligule a fringed membrane, or a fringe of hairs (the fringe dense).
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets. The spikelets all alike in sexuality; hermaphrodite; homomorphic.
Inflorescence. Inflorescence axillary, of spicate main branches (racemes); subdigitate. Primary inflorescence branches (1–)2–4. Inflorescence espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes racemes (spicate, longer than the common peduncle). The racemes without spikelets towards the base (pedunculate). Spikelet-bearing axes paired to clustered (very rarely solitary); with very slender rachides; disarticulating; disarticulating at the joints. Articles densely long-hairy (with basal tufts of brown hairs). Spikelets paired; sessile and pedicellate; consistently in long-and-short combinations; in pedicellate/sessile combinations. Pedicels of the pedicellate spikelets free of the rachis. The shorter spikelets hermaphrodite. The longer spikelets hermaphrodite (i.e., the spikelets homogamous).
Female-fertile spikelets. Spikelets 3.5–7 mm long (silky-villous); compressed dorsiventrally; falling with the glumes (the pedicellate spikelet falling from the pedicel, the sessile one falling with the joint). Rachilla terminated by a female-fertile floret. Hairy callus present (with tufts of hairs on the sessile spikelet/joint unit and at the base of the spikelet). The callus hairs brown. Callus blunt.
Glumes two; more or less equal (the G2 somewhat longer); long relative to the adjacent lemmas; rufously hairy; with distinct hair tufts; awned (the upper shortly so, sometimes), or awnless; carinate (G2), or non-carinate (G1); very dissimilar (the G1 rounded dorsally, 2–3 toothed, muticous, the G2 keeled, notched or cuspidate or aristulate). Lower glume not two-keeled; convex on the back (with raised nerves); not pitted; relatively smooth. Spikelets with incomplete florets. The incomplete florets proximal to the female-fertile florets. Spikelets with proximal incomplete florets. The proximal incomplete florets 1 (better developed than in Eulalia); paleate. Palea of the proximal incomplete florets fully developed. The proximal incomplete florets male, or sterile. The proximal lemmas awnless; 0 nerved; not becoming indurated (hyaline).
Female-fertile florets 1. Lemmas linear; less firm than the glumes (hyaline); not becoming indurated; incised; minutely 2 lobed; not deeply cleft (2-toothed); awned. Awns 1; median; from a sinus; geniculate; much longer than the body of the lemma. Lemmas non-carinate; without a germination flap; 1 nerved. Palea present; conspicuous but relatively short (short, broadly ovate); entire (obtuse); awnless, without apical setae (ciliate or glabrous); nerveless; keel-less. Lodicules present; 2; free; ciliate (each with a tuft of long hairs). Stamens 3. Ovary apically glabrous. Stigmas 2.
Fruit, embryo and seedling. Fruit ellipsoid.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells markedly different in shape costally and intercostally (the costals narrower, more regularly rectangular); of similar wall thickness costally and intercostally (the walls of medium thickness). Mid-intercostal long-cells rectangular to fusiform; having markedly sinuous walls to having straight or only gently undulating walls (the sinuosity fairly fine to negiligible). Microhairs present; elongated; clearly two-celled; panicoid-type. Stomata common. Subsidiaries non-papillate; dome-shaped (mostly low domes). Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells common; in cork/silica-cell pairs, or not paired. No macrohairs or prickles seen. Costal short-cells conspicuously in long rows. Costal silica bodies present and well developed; panicoid-type; butterfly shaped to dumb-bell shaped.
Transverse section of leaf blade, physiology. C4. The anatomical organization somewhat unconventional (in that the minor bundles are so crowded as to be almost superposed). XyMS. Leaf blade adaxially flat (with slight abaxial ribs beneath the primary bundles). Midrib conspicuous (with a pointed keel, an adaxial group of bulliforms, and midrib hinges); having a conventional arc of bundles; with colourless mesophyll adaxially (in that there may be a few colourless cells beneath the adaxial bulliform group), or without colourless mesophyll adaxially (?). The lamina symmetrical on either side of the midrib. Bulliforms present in discrete, regular adaxial groups; associating with colourless mesophyll cells to form arches over small vascular bundles. Many of the smallest vascular bundles unaccompanied by sclerenchyma. Combined sclerenchyma girders present (with the primaries); forming figures (large anchors and Is). Sclerenchyma all associated with vascular bundles.
Classification. Watson & Dallwitz (1994): Panicoideae; Andropogonodae; Andropogoneae; Andropogoninae. Soreng et al. (2015): Panicoideae; Andropogonodae; Andropogoneae; Saccharinae. 2 species.
Distribution, phytogeography, ecology. India and Southeast Asia.
Species of open habitats. Dry hillsides.
Economic aspects. E. binata used for making paper, mats, rope and string.
Rusts and smuts. Smuts from Ustilaginaceae. Ustilaginaceae Ustilago.
References, etc. Morphological/taxonomic: Bor 1957a. Leaf anatomical: studied by us - E. binata (Retz.) C.E. Hubb.
Special comments. Fruit data wanting. Illustrations. • E. binata, as Ischaemum angustifolium: Hook. Ic. Pl. 18 (1888)
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, and classifications. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., Macfarlane, T.D., and Dallwitz, M.J. 1992 onwards. The 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. Version: 11th December 2017. delta-intkey.com/grass’.