The grass genera of the world
~ Deyeuxia (D. uncinioides (S.T Blake) Royen & Veldk.)
Habit, vegetative morphology. Perennial; caespitose. Culms 6–10 cm high; herbaceous; unbranched above; 2 noded. Young shoots intravaginal. Leaves mostly basal; non-auriculate. Leaf blades linear; narrow; 0.4–0.6 mm wide; setaceous; rolled (convolute); without cross venation; persistent. Ligule an unfringed membrane; not truncate (ovate, lacerate); 1.1–1.5 mm long.
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence paniculate; contracted; spicate; espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate (the pedicels 0.5–0.8 mm long); imbricate.
Female-fertile spikelets. Spikelets 3.5–4 mm long; compressed laterally; disarticulating above the glumes. Rachilla prolonged beyond the uppermost female-fertile floret; prolongation hairy; the rachilla extension naked. Hairy callus present. Callus short; blunt.
Glumes two; more or less equal (subequal); shorter than the spikelets; shorter than the adjacent lemmas; hairless; scabrous; subacute; awnless; carinate; similar (thinly cartilaginous). Lower glume shorter than the lowest lemma; 1 nerved. Upper glume 1 nerved, or 3 nerved. Spikelets with female-fertile florets only.
Female-fertile florets 1. Lemmas convolute; similar in texture to the glumes (thinly cartilaginous); incised; 2 lobed (minutely bilobed); not deeply cleft; awned. Awns 1; median; dorsal; from near the top; hooked; non-geniculate; hairless; much shorter than the body of the lemma (0.7 – 1.2 mm long); entered by one vein; persistent. Lemmas hairless; glabrous; carinate; 5 nerved; with the nerves non-confluent. Palea present; conspicuous but relatively short (about 2/3 of the lemma length); entire (obtuse); awnless, without apical setae; textured like the lemma; not indurated; 2-nerved; 2-keeled. Palea keels wingless; glabrous. Lodicules present; 2; free; membranous; glabrous; not toothed; not or scarcely vascularized (hyaline). Stamens 3. Anthers 0.6 mm long; not penicillate; without an apically prolonged connective. Ovary apically glabrous. Styles fused. Stigmas 2.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Mid-intercostal long-cells rectangular and fusiform; having markedly sinuous walls. Microhairs absent. Stomata common. Subsidiaries predominantly dome-shaped. Guard-cells overlapping to flush with the interstomatals (mostly more or less flush). Intercostal short-cells common; in cork/silica-cell pairs; silicified. Intercostal silica bodies mostly crescentic. Costal short-cells predominantly paired, or neither distinctly grouped into long rows nor predominantly paired (a few short rows). Costal silica bodies horizontally-elongated crenate/sinuous (predominating over most veins: a short variant of the crenate type), or tall-and-narrow to crescentic (a few).
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; without adaxial palisade. Leaf blade with distinct, prominent adaxial ribs (the tops rounded); with the ribs more or less constant in size. Midrib not readily distinguishable (except by its location); with one bundle only. Bulliforms present in discrete, regular adaxial groups; in simple fans (in each furrow). All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders absent (adaxially with strands only, abaxially with girders and strands). Sclerenchyma all associated with vascular bundles.
Classification. Watson & Dallwitz (1994): Pooideae; Poodae; Aveneae. Soreng et al. (2015): Pooideae; Poodae; Poeae; Agrostidinae. 2 species.
Distribution, phytogeography, ecology. Montane New Guinea.
Mesophytic. Damp places and montane grassland.
References, etc. Morphological/taxonomic: Blake 1946. Leaf anatomical: this project.
Special comments. Fruit data wanting. Illustrations. • Spikelet of A. uncinioides. • Lemma tip with hooked awn (A. uncinioides)
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: 13th November 2017. delta-intkey.com/grass’.