| # The grass genera of the world |

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

### Stilpnophleum Nevski

~ Deyeuxia, Calamagrostis

Habit, vegetative morphology. Perennial; caespitose. Culms herbaceous. Leaves non-auriculate. Leaf blades narrow; not pseudopetiolate; without cross venation. Ligule present; an unfringed membrane; not truncate; 3–8 mm long.

Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets.

Inflorescence. Inflorescence paniculate; contracted; capitate to spicate; espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.

Female-fertile spikelets. Spikelets 5–7 mm long; not noticeably compressed; disarticulating above the glumes. Rachilla prolonged beyond the uppermost female-fertile floret; hairy; the rachilla extension naked. Hairy callus present.

Glumes two; more or less equal; long relative to the adjacent lemmas; pointed (acute to acuminate); awnless; carinate; similar (lanceolate or lanceolate-ovate). Lower glume 1 nerved. Upper glume 1 nerved. Spikelets with female-fertile florets only.

Female-fertile florets 1. Lemmas similar in texture to the glumes; not becoming indurated; incised; not deeply cleft (toothed?); awned. Awns 1; median; dorsal; usually from well down the back; geniculate. Lemmas hairless; non-carinate; without a germination flap; 5 nerved. Palea present; relatively long; 2-nerved; 2-keeled, or keel-less. Lodicules present; 2; free; membranous; glabrous; usually toothed; not or scarcely vascularized. Stamens 3. Ovary apically glabrous. Styles free to their bases. Stigmas 2.

Fruit, embryo and seedling. Fruit longitudinally grooved. Hilum short. Embryo small.

Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Mid-intercostal long-cells fusiform (mostly); having markedly sinuous walls (some, slightly), or having straight or only gently undulating walls. Microhairs absent. Stomata common; (33–)36–42(–45) microns long. Subsidiaries parallel-sided. Guard-cells overlapped by the interstomatals (clearly sunken). Intercostal short-cells absent or very rare. Prickles present over the veins. Costal short-cells neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies horizontally-elongated crenate/sinuous and horizontally-elongated smooth; not sharp-pointed.

Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll without adaxial palisade. Leaf blade with distinct, prominent adaxial ribs to ‘nodular’ in section; with the ribs very irregular in sizes (large alternating with small). Midrib not readily distinguishable; with one bundle only. Bulliforms present in discrete, regular adaxial groups; in simple fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present (with the primaries); forming ‘figures’. Sclerenchyma all associated with vascular bundles.

Classification. Watson & Dallwitz (1994): Pooideae; Poodae; Aveneae. Soreng et al. (2015): Pooideae (as a synonym); Poodae; Poeae; Agrostidinae. 1 species (S. anthoxanthoides).

Distribution, phytogeography, ecology. Russia.

References, etc. Leaf anatomical: studied by us - S. anthoxanthoides (Munro) Nevski.

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: 15th June 2025. delta-intkey.com’.

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