| # The grass genera of the world |

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

### Stephanachne Keng

Including Pappagrostis Roshev.

Habit, vegetative morphology. Perennial; caespitose. Culms herbaceous. Leaves non-auriculate. Leaf blades not pseudopetiolate; without cross venation. Ligule an unfringed membrane; not truncate; 1–2 mm long.

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

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

Female-fertile spikelets. Spikelets 4.5–7 mm long; not noticeably compressed; disarticulating above the glumes. Rachilla prolonged beyond the uppermost female-fertile floret; the rachilla extension naked. Hairy callus present.

Glumes two; more or less equal; about equalling the spikelets; long relative to the adjacent lemmas; pointed (acuminate); awnless; carinate, or non-carinate; similar (membranous or herbaceous). Lower glume 1–3 nerved. Upper glume 3 nerved. Spikelets with female-fertile florets only; without proximal incomplete florets.

Female-fertile florets 1. Lemmas decidedly firmer than the glumes (thinly leathery); not becoming indurated; incised; 2 lobed; deeply cleft to not deeply cleft (notched, or cleft to a third of its length); awned. Awns 1, or 3 (by extension from the acuminate lobes); median, or median and median and lateral; the median different in form from the laterals; from a sinus; geniculate. Lemmas hairy. The hairs in tufts; in transverse rows (with a long transverse tuft at the base of each glabrous lobe). Lemmas non-carinate; without a germination flap; 5 nerved. Palea present; relatively long; 2-nerved; keel-less. Palea back hairy. Lodicules present; 2 (Pappagrostis), or 3; free; membranous; glabrous; not toothed; not or scarcely vascularized. Stamens 3. Ovary apically glabrous. Styles free to their bases. Stigmas 2.

Fruit, embryo and seedling. Fruit small (about 3 mm long). Hilum long-linear. Embryo small.

Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells differing markedly in wall thickness costally and intercostally (costals thicker-walled). Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs absent. Stomata common; 27–30 microns long. Subsidiaries parallel-sided. Guard-cells overlapped by the interstomatals. Intercostal short-cells fairly common; not paired (mostly solitary); not silicified. Costal short-cells neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies absent, or poorly developed (in the material seen).

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. 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.

Cytology. Chromosome base number, x = 12 (or 6). 2n = 24.

Classification. Watson & Dallwitz (1994): Pooideae; Poodae; Aveneae. Soreng et al. (2015): Pooideae; Phaenospermateae. 2 species.

Distribution, phytogeography, ecology. China, eastern Russia.

References, etc. Leaf anatomical: studied by us - S. (Pappagrostis) pappophorea.

Illustrations. • Stephanachne pappophorea: See legend for reference.

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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