The grass genera of the world
Type species: D. hayachinensis.
Habit, vegetative morphology. Perennial; rhizomatous, or stoloniferous, or caespitose. Culms solitary, geniculately ascending 30–60 cm high; herbaceous; unbranched above; 2–3 noded. Sheath margins joined (to about half their length). Leaf blades acuminate, narrow; 7–18 cm long, 4–6 mm wide. Ligule an unfringed membrane; acute, not truncate; 0.5–1 mm long.
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets. The spikelets hermaphrodite.
Inflorescence. Inflorescence paniculate; nodding, open; espatheate; not comprising partial inflorescences and foliar organs. Spikelets solitary; not secund; pedicellate.
Female-fertile spikelets. Spikelets 7–8 mm long; oblong to elliptic; compressed laterally; disarticulating above the glumes; disarticulating between the florets. Rachilla prolonged beyond the uppermost female-fertile floret; the rachilla extension with incomplete florets. Hairy callus present (with a crown of hairs around the lemma base).
Glumes two; very unequal to more or less equal; shorter than the spikelets; shorter than the adjacent lemmas; awnless; carinate; membranous, lanceolate, acuminate similar. Lower glume 0.75 times the length of the upper glume; shorter than the lowest lemma; 1 nerved. Upper glume 3 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets merely underdeveloped; awnless.
Female-fertile florets 3–5. Lemmas lanceolate, laterally compressed; similar in texture to the glumes (membranous); not becoming indurated; entire; pointed; attenuately awned. Awns 1; median; apical; non-geniculate; hairless. Lemmas basally hairy; carinate; 3 nerved (Soreng et al.), or 5 nerved (Clayton et al.). Palea present; 2-keeled. Palea keels scabrous. Lodicules present; 2; membranous. Stamens 3. Anthers 2.5–3 mm long; without an apically prolonged connective.
Fruit, embryo and seedling. Fruit not grooved. Hilum short. Pericarp fused.
Classification. Watson & Dallwitz (1994): not described separately. Soreng et al. (2015): Pooideae; Poodae; Poeae; Poinae. 1 species (D. hayachinensis).
Distribution, phytogeography, ecology. Northern Japan.
Not known in Australasia.
Helophytic (in wet, gravelly, alpine serpentine habitats).
References, etc. Morphological/taxonomic: Soreng et al. (2015). Molecular and morphological evidence for a new grass genus, Dupontiopsis (Poaceae tribe Poeae subtribe Poinae s.l., endemic to alpine Japan, and implications for the reticulate origin of Dupontia and Arctophila within Poinae s.l.; Clayton et al., GrassBase (2016).
Special comments. Fruit data wanting. Anatomical data wanting.
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’.