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DELTA sample data

M. J. Dallwitz and L. Watson

Poa L.

Including Arctopoa (Griseb.) Probat., Neuropoa Clayton, Oreopoa Grand., Paneion Lunell, Parodiochloa C.E. Hubb., Poagrostis Raf.

Habit, vegetative morphology. Annual, or perennial. Culms (1–)4–150 cm high; herbaceous; unbranched above. Leaf blades linear, or linear-lanceolate (often ending in a boat-shaped tip); 0.2–12 mm wide (rarely wider). Ligule an unfringed membrane, or a fringed membrane (rarely).

Inflorescence. Plants bisexual, with bisexual spikelets, or dioecious (or gynodioecious, in subgenus Andinae). Inflorescence paniculate; open, or contracted; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund.

Female-fertile spikelets, florets, fruit. Spikelets 2–11 mm long; compressed laterally; disarticulating above the glumes; disarticulating between the florets. Rachilla prolonged beyond the uppermost female-fertile floret. Hairy callus present, or absent. Glumes two; more or less equal, or very unequal to more or less equal (nearly always ‘subequal’, with the G1 somewhat shorter); shorter than the adjacent lemmas; awnless; carinate. Upper glume (1–)3(–5) nerved. Spikelets with female-fertile florets only, or with incomplete florets. The incomplete florets distal to the female-fertile florets. Female-fertile florets (1–)2–13(–15) (the one-floreted species very unusual, perhaps restricted to Malesia). Lemmas nearly always entire (very rarely tridenticulate); pointed; awnless, or mucronate (2–3 mm terminal ‘awns’ in a very few species, e.g. in the southern South American P. flabellata); carinate; without a germination flap; (3–)5 nerved, or 7–11 nerved (rarely, e.g. in the Australian Neuropoa). Palea present; relatively long, or conspicuous but relatively short. Lodicules present; membranous; nearly always glabrous (occasionally ciliolate). Stamens 3. Ovary glabrous. Stigmas 2; white. Fruit small. Hilum short.

Photosynthetic pathway, leaf blade anatomy. C3; XyMS+. Midrib conspicuous; with one bundle only. Many of the smallest vascular bundles unaccompanied by sclerenchyma, or all the vascular bundles accompanied by sclerenchyma.

Taxonomy, distribution. Pooideae; Poodae; Poeae. About 500 species. Holarctic, Paleotropical, Neotropical, Australian, and Antarctic.

Anatomical references. Mainly Metcalfe 1960; this project.

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, and distributions of character states within any set of taxa. See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1998 onwards. DELTA sample data: descriptions, illustrations, identification, and information retrieval. Version: 19th October 2016.’.