The grass genera of the world
Type species: P. marginata.
Habit, vegetative morphology. Perennial; rhizomatous and caespitose. The flowering culms leafy. Culms 1500–2000 cm high; woody and persistent (with aerial roots); to 2.5 cm in diameter; cylindrical; not scandent; leaning, apically pendulous; branched above (from mid-culm). Buds from which the primary culm branches arise 1. Primary branches thinner than the stem, 2–3 (with one dominant); clumped. The branching dendroid. Culm leaf sheaths present (with an external ligule); deciduous; leaving a persisten girdle (this rugose); conspicuously auriculate (these falcate, setose). Culm leaves with conspicuous blades. Culm leaf blades narrower than the sheaths, acuminate, ovate. Culm internodes hollow. Loosely clumped. Rhizomes pachymorph. Leaf blades basally asymmetric, acuminate, lanceolate; broad; 17–41 cm long, 17–33 mm wide; pseudopetiolate; disarticulating from the sheaths.
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets. The spikelets hermaphrodite.
Inflorescence. Inflorescence indeterminate; with pseudospikelets (these with axillary basal buds); of spicate main branches (bearing synflorescences with globose nodal clusters, leafless between the clusters); spatheate; a complex of partial inflorescences and intervening foliar organs (bractiferous, with spathaceous subtending bracts).
Female-fertile spikelets. Spikelets unconventional; 4–5 mm long; lanceolate; compressed laterally; disarticulating above the glumes; disarticulating between the florets; "with definite rachilla internodes". Rachilla terminated by a female-fertile floret.
Glumes two; shorter than the spikelets; shorter than the adjacent lemmas; pointed; awnless; ovate, acute, similar. Lower glume about as long as the upper one; shorter than the lowest lemma. Spikelets with female-fertile florets only.
Female-fertile florets 5–7. Lemmas ovate,3.5–4.5 mm long; smooth; entire; pointed; acuminate, awnless; hairless; glabrous; non-carinate. Palea present; relatively long (4–5 mm long); entire; awnless, without apical setae (the apex acute). Lodicules absent. Stamens 6. Anthers yellow, 2 mm long. Stigmas 3.
Fruit, embryo and seedling. Pericarp fused.
Classification. Watson & Dallwitz (1994): not described separately. Soreng et al. (2015): Bambusoideae (? - not listed); Bambusodae (?); Bambuseae (?); Bambusinae (?). 1 species (P. marginata).
Distribution, phytogeography, ecology. Papuasia.
References, etc. Morphological/taxonomic: Clayton et al. (2016), GrassBase.
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: 11th December 2017. delta-intkey.com/grass’.