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The grass genera of the world

L. Watson, T.D. Macfarlane, and M.J. Dallwitz

Pseudozoysia Chiov.

Habit, vegetative morphology. Perennial. Culms herbaceous. Leaf blades narrow; setaceous; rolled (involute); without cross venation.

Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets. The spikelets all alike in sexuality.

Inflorescence. Inflorescence a false spike, with spikelets on contracted axes (cylindrical, of short ‘racemelets’, basally enclosed in the upper leaf sheatrh); espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes very much reduced (to two contiguous spikelets); disarticulating (?); falling entire (the racemelets falling, cf. Tragus etc.?). Spikelets paired; not secund; consistently in ‘long-and-short’ combinations. The ‘shorter’ spikelets hermaphrodite. The ‘longer’ spikelets hermaphrodite.

Female-fertile spikelets. Spikelets not noticeably compressed (?); falling with the glumes (with the racemelet?). Rachilla terminated by a female-fertile floret. Hairy callus absent.

Glumes two; relatively large; exceeding the spikelets; long relative to the adjacent lemmas; hairless; not pointed; awnless; non-carinate; very dissimilar (indurated, tuberculate, acute, the lower ovate, the upper subglobose). Lower glume and the upper tuberculate. Upper glume distinctly saccate (enclosing the floret). Spikelets with female-fertile florets only.

Female-fertile florets 1. Lemmas less firm than the glumes (scarious); not becoming indurated; entire; blunt; awnless; hairless; non-carinate; without a germination flap. Palea present; conspicuous but relatively short (about half as long as the lemma); not indurated.

Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Microhairs present; chloridoid-type. Stomata common. Subsidiaries dome-shaped and triangular. Intercostal short-cells common (fairly); not paired (mainly solitary). Costal short-cells conspicuously in long rows. Costal silica bodies ‘panicoid-type’; dumb-bell shaped; not sharp-pointed.

Transverse section of leaf blade, physiology. Lamina mid-zone in transverse section open.

C4; XyMS+. Bulliforms present in discrete, regular adaxial groups; probably 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’. Sclerenchyma all associated with vascular bundles.

Classification. Watson & Dallwitz (1994): Chloridoideae; main chloridoid assemblage. Soreng et al. (2015): Chloridoideae. 1 species (P. sessilis).

Distribution, phytogeography, ecology. Somalia.

Xerophytic; species of open habitats; halophytic. In coastal sand dunes.

References, etc. Leaf anatomical: this project.

Special comments. Fruit data wanting.

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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: 13th November 2017.’.