Vahlodea Fries
Sometimes referred to Deschampsia
Habit, vegetative morphology. Perennial; rhizomatous, or caespitose. Culms 15–80 cm high; herbaceous. Culm nodes glabrous. Culm internodes hollow. Leaves not basally aggregated; non-auriculate. Sheath margins free. Leaf blades linear; narrow; 1–5 mm wide; flat; without cross venation; persistent; rolled in bud; an unfringed membrane; truncate, or not truncate (dentate or lacerate); 2 mm long.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence paniculate; open; with capillary branchlets; espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.
Female-fertile spikelets. Spikelets 2–5.5 mm long; compressed laterally to not noticeably compressed; disarticulating above the glumes; disarticulating between the florets. Rachilla prolonged beyond the uppermost female-fertile floret; the rachilla extension naked. Hairy callus present (the hairs 1/2 to 2/3 as long as the lemma). Callus hairs present, more than 0.5 mm long.
Glumes present; two; more or less equal; exceeding the spikelets; long relative to the adjacent lemmas (about twice as long); pointed (acute); awnless; carinate; similar. Lower glume 1 nerved. Upper glume 3 nerved. Spikelets with female-fertile florets only; without proximal incomplete florets.
Female-fertile florets 2–3. Lemmas similar in texture to the glumes; not becoming indurated; entire; blunt; awned. Awns 1; median; dorsal; from near the top, or from well down the back; geniculate; proximally hairy. Lemmas hairy (above), or hairless (glabrous above the callus); non-carinate; without a germination flap; 5 nerved. Palea present; relatively long; 2-nerved; 2-keeled. Lodicules present; 2; free; membranous; glabrous; toothed, or not toothed; not or scarcely vascularized. Stamens 3. Anthers 0.4–0.8 mm long. Ovary glabrous. Styles free to their bases. Stigmas 2; white.
Fruit, embryo and seedling. Fruit adhering to lemma and/or palea, or free from both lemma and palea. Embryo small. Endosperm hard.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells markedly different in shape costally and intercostally (costals more rectangular); differing markedly in wall thickness costally and intercostally (costals thicker-walled). Mid-intercostal long-cells fusiform; having straight or only gently undulating walls. Microhairs absent. Stomata common; (21–)24–33(–36) microns long. Subsidiaries parallel-sided. Guard-cells overlapped by the interstomatals. Intercostal short-cells absent or very rare. Prickle bases abundant. Costal zones with short-cells. Costal short-cells neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies horizontally-elongated crenate/sinuous, or horizontally-elongated smooth (few); not sharp-pointed.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; without adaxial palisade. Leaf blade ‘nodular’ in section to adaxially flat. Midrib not readily distinguishable; with one bundle only. Bulliforms present in discrete, regular adaxial groups; in simple fans (these wide, shallow). All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present (with the primaries only); nowhere forming ‘figures’. Sclerenchyma all associated with vascular bundles.
Cytology. Chromosome base number, x = 7. 2n = 14. 2 ploid. Chromosomes ‘large’. Haploid nuclear DNA content 3.2 pg (1 species).
Taxonomy. Pooideae; Poodae; Aveneae.
Distribution, ecology, phytogeography. 3–4 species; northeast Asia. Helophytic (calcifuge).
Holarctic and Antarctic. Boreal. Arctic and Subarctic and Euro-Siberian. Patagonian. European and Siberian.
References, etc. Leaf anatomical: 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).