Eragrostiella Bor
Eragrostiella: a diminutive of Eragrostis (a related genus, q.v.).
Habit, vegetative morphology. Perennial; compactly caespitose. Culms 20–50 cm high; herbaceous. Culm internodes hollow. Leaves usually mostly basal; non-auriculate. Leaf blades narrow; setaceous, or not setaceous (often filiform, rarely flat); without abaxial multicellular glands; without cross venation; persistent; a fringed membrane; short.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets. The spikelets all alike in sexuality.
Inflorescence. Inflorescence a single spike, or a single raceme (long-pedunculate). Inflorescence with axes ending in spikelets. Inflorescence espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets secund; biseriate; subsessile, or pedicellate.
Female-fertile spikelets. Spikelets 6–20 mm long; compressed laterally; disarticulating above the glumes; tardily disarticulating between the florets, or not disarticulating between the florets (the paleas persistent). Rachilla prolonged beyond the uppermost female-fertile floret; hairy; the rachilla extension with incomplete florets. Hairy callus absent.
Glumes present; two; more or less equal; shorter than the spikelets; shorter than the adjacent lemmas, or long relative to the adjacent lemmas; awnless; carinate (the lower), or non-carinate (the upper being keeled only at the tip); very dissimilar. Lower glume 1 nerved. Upper glume 3 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets merely underdeveloped. Spikelets without proximal incomplete florets.
Female-fertile florets 6–50. Lemmas less firm than the glumes to similar in texture to the glumes (membranous to cartilaginous); not becoming indurated; entire to incised (acute to emarginate); not deeply cleft; awnless; hairless; glabrous; carinate. The keel wingless. Lemmas without a germination flap; 3 nerved. Palea present (persistent); relatively long; entire; awnless, without apical setae; 2-nerved; 2-keeled. Palea keels narrowly to broadly winged. Lodicules present; 2; fleshy. Anthers not penicillate. Ovary glabrous. Stigmas 2.
Fruit, embryo and seedling. Fruit ellipsoid; not noticeably compressed (terete), or trigonous; sculptured (reticulate-striate). Pericarp fused (?). Embryo large; with an epiblast; with a scutellar tail; with an elongated mesocotyl internode. Embryonic leaf margins meeting.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells similar in shape costally and intercostally; of similar wall thickness costally and intercostally. Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs present; more or less spherical; clearly two-celled; chloridoid-type. Microhair apical cell wall of similar thickness/rigidity to that of the basal cell. Microhairs 14–18 microns long. Microhair basal cells 9 microns long. Microhairs 12(–13.5) microns wide at the septum. Microhair total length/width at septum 1.4–1.8. Microhair apical cells 7–12 microns long. Microhair apical cell/total length ratio 0.4–0.73. Stomata common; 22.5–25.5 microns long. Subsidiaries low dome-shaped, or triangular. Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells common; in cork/silica-cell pairs; silicified. Intercostal silica bodies imperfectly developed; saddle shaped (small), or tall-and-narrow. Costal short-cells conspicuously in long rows, or neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies present in alternate cell files of the costal zones; saddle shaped.
Transverse section of leaf blade, physiology. Lamina mid-zone in transverse section open.
C4; XyMS+. PCR sheath outlines even. PCR sheaths of the primary vascular bundles interrupted; interrupted abaxially only. PCR sheath extensions present, or absent. Maximum number of extension cells 1–2. Mesophyll with radiate chlorenchyma; traversed by columns of colourless mesophyll cells. Leaf blade with distinct, prominent adaxial ribs, or adaxially flat; with the ribs more or less constant in size. Midrib not readily distinguishable; with one bundle only. Bulliforms present in discrete, regular adaxial groups; associated with colourless mesophyll cells to form deeply-penetrating fans (these linked with traversing columns of colourless cells). All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’. Sclerenchyma all associated with vascular bundles. The lamina margins with fibres.
Taxonomy. Chloridoideae; main chloridoid assemblage.
Distribution, ecology, phytogeography. 5 species; India, Burma, Ceylon, Australia. Xerophytic; species of open habitats. Dry grassland and bush, on thin soils.
Paleotropical and Australian. African and Indomalesian. Saharo-Sindian and Sudano-Angolan. Indian and Indo-Chinese. North and East Australian. Somalo-Ethiopian. Tropical North and East Australian.
Rusts and smuts. Smuts from Tilletiaceae. Tilletiaceae — Tilletia.
References, etc. Leaf anatomical: Metcalfe 1960; this project.
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).