Psammochloa A. Hitchc.
Habit, vegetative morphology. Robust perennial; rhizomatous to stoloniferous. Culms 20–120 cm high (? - ‘resembling Ammophila in appearance’); herbaceous. Culm nodes hidden by leaf sheaths. Leaves non-auriculate. Leaf blades broad (loosely inrolled); not pseudopetiolate; an unfringed membrane; up to 5–10 mm long.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets. The spikelets all alike in sexuality.
Inflorescence. Inflorescence paniculate; open (diffuse); espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.
Female-fertile spikelets. Spikelets not noticeably compressed; disarticulating above the glumes. Rachilla terminated by a female-fertile floret. Hairy callus absent.
Glumes two; more or less equal; somewhat shorter than the spikelets to exceeding the spikelets; long relative to the adjacent lemmas (sometimes slightly shorter than them); awnless; non-carinate; similar. Lower glume 5–7 nerved. Upper glume 5–7 nerved. Spikelets with female-fertile florets only; without proximal incomplete florets.
Female-fertile florets 1. Lemmas not convolute; decidedly firmer than the glumes; not becoming indurated (chartaceous); entire to incised (square to slightly notched); not deeply cleft; awned. Awns 1; median; from a sinus to dorsal; non-geniculate; straight; deciduous. Lemmas densely hairy; non-carinate; 7–9 nerved. Palea present; relatively long (closely resembling the lemma); entire (acute); textured like the lemma; several nerved (5–9 nerved, hairy); keel-less. Lodicules present; 3; free; membranous; ciliate (near apex); not toothed; not or scarcely vascularized. Stamens 3. Anthers penicillate, or not penicillate. Ovary glabrous. Styles free to their bases. Stigmas 2; white.
Fruit, embryo and seedling. Fruit free from both lemma and palea; medium sized, or large (8–11 mm long); not noticeably compressed. Hilum long-linear. Pericarp free. Embryo small; not waisted. Endosperm hard; containing compound starch grains. Embryo with an epiblast; without a scutellar tail; with a negligible mesocotyl internode. Embryonic leaf margins meeting.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Mid-intercostal long-cells having markedly sinuous walls. Microhairs absent. Stomata common; (31.5–)34.5–36(–39) microns long. Subsidiaries low to high dome-shaped, or triangular. Intercostal short-cells common; not paired (arranged like the costals); silicified. Intercostal silica bodies cubical. Costal short-cells neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies horizontally-elongated smooth, rounded, and tall-and-narrow (or cubical); not sharp-pointed.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma. Leaf blade with distinct, prominent adaxial ribs; with the ribs very irregular in sizes. Midrib not readily distinguishable; with one bundle only. Bulliforms present in discrete, regular adaxial groups (at the bases of the furrows); in simple fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present (with all the bundles); forming ‘figures’. Sclerenchyma not all bundle-associated. The ‘extra’ sclerenchyma in abaxial groups (in the form of small abaxial strands midway between the bundles).
Taxonomy. Stipoideae; Stipeae.
Distribution, ecology, phytogeography. 1 species; Gobi Desert. Xerophytic; species of open habitats. A robust, Ammophila-like sandbinder.
Holarctic. Tethyan. Irano-Turanian.
Rusts and smuts. Rusts — Puccinia.
References, etc. Morphological/taxonomic: Bor 1951; Macfarlane and Watson 1980. 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).