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The grass genera of the world

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

Hyalopoa (Tzvelev) Tzvelev

~ Colpodium

Habit, vegetative morphology. Perennial; caespitose. Culms 15–70 cm high; herbaceous; unbranched above. Culm nodes glabrous. Leaves not basally aggregated. Leaf blades narrow; 1–6 mm wide (by 4–15 cm long); flat; not pseudopetiolate; without cross venation; persistent.

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

Inflorescence. Inflorescence paniculate; open (effuse, nodding, the branches flexuose); espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not in distinct ‘long-and-short’ combinations.

Female-fertile spikelets. Spikelets 5–10 mm long; compressed laterally; disarticulating above the glumes. Rachilla prolonged beyond the uppermost female-fertile floret. Hairy callus absent. Callus short; blunt.

Glumes two; very unequal; shorter than the spikelets; shorter than the adjacent lemmas; not pointed (rounded-denticulate); awnless; non-carinate; similar (cuneate to lanceolate, often purple-tipped). Lower glume longer than half length of lowest lemma; 1 nerved. Upper glume 1 nerved, or 3 nerved. Spikelets with female-fertile florets only, or 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 2–4. Lemmas decidedly firmer than the glumes (leathery below); not becoming indurated; entire, or incised (very slightly); pointed, or blunt; not deeply cleft; awnless; hairy (pilose below, between the ciliate nerves); carinate. The keel slightly winged. Lemmas without a germination flap; 3 nerved, or 5 nerved. Palea present; relatively long; awnless, without apical setae; 2-nerved; 2-keeled. Palea keels wingless. Lodicules present; 2; free; membranous; glabrous; not toothed; not or scarcely vascularized. Stamens 3. Anthers 1.5–3.5 mm long. Ovary apically glabrous. Styles free to their bases. Stigmas 2; white.

Fruit, embryo and seedling. Fruit free from both lemma and palea; small (1.8–2.5 mm long). Hilum short. Embryo small.

Cytology. Chromosome base number, x = 7. 2n = 42. 6 ploid. Chromosomes ‘large’.

Classification. Watson & Dallwitz (1994): Pooideae; Poodae; Aveneae. Soreng et al. (2015): Pooideae; Poodae; Poeae; Coleanthinae. 4 species.

Distribution, phytogeography, ecology. Caucasus, Turkey, northwest Himalaya, northeast Siberia.

Helophytic (moist upland habitats); species of open habitats; glycophytic.

References, etc. Morphological/taxonomic: Bor 1970 (under Colpodium).

Special comments. Anatomical 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. delta-intkey.com/grass’.

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