Zenkeria Trin.
Habit, vegetative morphology. Perennial; caespitose. Culms 60–130 cm high; herbaceous. Leaf blades broad, or narrow; 5–25 mm wide; flat, or rolled (convolute or involute); pseudopetiolate (the pseudopetiole stiff); without cross venation; a fringe of hairs.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence paniculate; open, or contracted; espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.
Female-fertile spikelets. Spikelets 2.5–4 mm long; compressed laterally; disarticulating above the glumes. Rachilla very shortly prolonged beyond the uppermost female-fertile floret, or terminated by a female-fertile floret; hairy; the rachilla extension (when present) naked.
Glumes two; very unequal (G2 longer), or more or less equal; shorter than the spikelets; shorter than the adjacent lemmas; awnless; carinate; similar (spreading, ovate). Lower glume much shorter than half length of lowest lemma, or longer than half length of lowest lemma; 1 nerved. Upper glume 1 nerved. Spikelets with female-fertile florets only; without proximal incomplete florets.
Female-fertile florets 2 (similar). Lemmas similar in texture to the glumes to decidedly firmer than the glumes; not becoming indurated (leathery); awnless (acuminate in Z. elegans); hairy (below the middle); 5–7 nerved. Palea present; awnless, without apical setae, or with apical setae; 2-keeled. Palea keels hairy (long-ciliate). Lodicules present; 2; free; membranous. Stamens 3.
Fruit, embryo and seedling. Endosperm containing compound starch grains.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells markedly different in shape costally and intercostally; of similar wall thickness costally and intercostally. Mid-intercostal long-cells rectangular; having markedly sinuous walls (and pitted; but the sinuations very fine; by contrast with the coarse sinuations of the costals). Microhairs present; panicoid-type (large, the apical cell as long as the basal cell). Stomata common. Subsidiaries dome-shaped. Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells common; not paired (solitary (square-ish)); not silicified. Costal zones with short-cells. Costal short-cells conspicuously in long rows (though the short-cells sometimes rather long). Costal silica bodies oryzoid (very regular, cf. Pheidochloa); not sharp-pointed.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; without adaxial palisade; without arm cells (but the cell walls frequently very sinuous). Leaf blade with distinct, prominent adaxial ribs; with the ribs very irregular in sizes (large, flat-topped and a few small round-topped). Midrib not readily distinguishable; with one bundle only. Bulliforms present in discrete, regular adaxial groups (large groups, regularly disposed between the ribs); 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’ (all bundles). Sclerenchyma all associated with vascular bundles.
Taxonomy. Arundinoideae; Danthonieae.
Distribution, ecology, phytogeography. 4 species; India, Ceylon, Burma. Species of open habitats. Upland grassland.
Paleotropical. Indomalesian. Indian.
References, etc. Leaf anatomical: this project.
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).