The grass genera of the world
~ Cf. Triraphis, Crinipes
Type species: Type: P. welwitschii (Rendle) C.E.Hubbard.
Including Pentaschistis welwitschii
Habit, vegetative morphology. Slender, erect perennial; caespitose (the base tomentose and fibrous). Culms herbaceous; unbranched above. Leaves non-auriculate. Leaf blades narrow; setaceous (folded); without cross venation; disarticulating from the sheaths. Ligule present; a fringe of hairs.
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence determinate; without pseudospikelets; paniculate; open (lanceolate-oblong or narrowly oblong); with capillary branchlets; non-digitate; espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.
Female-fertile spikelets. Spikelets compressed laterally; disarticulating above the glumes; disarticulating between the florets; with conventional internode spacings (the internodes very short). Rachilla prolonged beyond the uppermost female-fertile floret; the rachilla extension naked.
Glumes two; relatively large; more or less equal (only slightly unequal); shorter than the spikelets; shorter than the adjacent lemmas; acute or the apex minutely toothed; awnless (but mucronate); similar (thinly membranous). Lower glume 1 nerved. Upper glume 1 nerved. Spikelets with female-fertile florets only.
Female-fertile florets 2. Lemmas not becoming indurated (herbaceous membranous, becoming firm); incised; 2 lobed; not deeply cleft (the lobes narrow, terminating in short setae); awned. Awns 1; median; from a sinus; non-geniculate to geniculate (very slender, curved or flexuose above but flattened and twisted at the base). Lemmas hairy (pilose on the margins); non-carinate (convex); 5–9 nerved. Palea present; relatively long; entire (obtuse), or apically notched; awnless, without apical setae; not indurated (thinly membranous); 2-nerved; 2-keeled. Lodicules present; 2; fleshy (minute); minutely ciliate, or glabrous. Stamens 3. Ovary apically glabrous. Styles free to their bases. Stigmas 2.
Fruit, embryo and seedling. Fruit not grooved; not noticeably compressed (terete). Hilum short (but linear). Embryo large.
Transverse section of leaf blade, physiology. Lamina mid-zone in transverse section open.
Classification. Watson & Dallwitz (1994): Arundinoideae, or Chloridoideae (?); if arundinoid, Danthonieae (?); if chloridoid, main chloridoid assemblage (?). Soreng et al. (2015): Arundinoideae; Molinieae. 1 species (P. welwitschii).
Distribution, phytogeography, ecology. Angola.
Mesophytic; species of open habitats. Damp rocky places.
References, etc. Morphological/taxonomic: Hubbard 1957.
Special comments. Taxonomic relationships impossible to determine reliably with neither leaf anatomical nor photosynthetic pathway data. 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: 11th December 2017. delta-intkey.com/grass’.