The grass genera of the world
The grass genera of the world | |
Sometimes referred to Trisetum
Habit, vegetative morphology. Perennial; caespitose. Culms 50–100 cm high; herbaceous; unbranched above. Young shoots intravaginal. Leaves non-auriculate; without auricular setae. Leaf blades linear; narrow; 2–8 mm wide; flat; without cross venation. Ligule an unfringed membrane (?).
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets. The spikelets all alike in sexuality; hermaphrodite.
Inflorescence. Inflorescence paniculate; open to contracted (8–20 cm long, nodding or erect); espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate; imbricate.
Female-fertile spikelets. Spikelets 5–7 mm long; compressed laterally; disarticulating above the glumes; disarticulating between the florets. Rachilla prolonged beyond the uppermost female-fertile floret; copiously hairy (pilose). Hairy callus present. Callus hairs present, more than 0.5 mm long (0.5–2 mm long). Callus short.
Glumes two; very unequal to more or less equal; (the upper) about equalling the spikelets; long relative to the adjacent lemmas (about as long); hairless; scabrous; pointed; awnless; carinate; similar. Spikelets with female-fertile florets only, or with incomplete florets (?). The incomplete florets (if they occur) distal to the female-fertile florets. The distal incomplete florets merely underdeveloped. Spikelets without proximal incomplete florets.
Female-fertile florets 2–3(–4) (‘two to several’). Lemmas not becoming indurated; entire; pointed to blunt; awnless (usually), or mucronate (rarely with a dorsal, subapical awn-point); hairless (above the callus); scabrous; carinate; without a germination flap; 5 nerved (or more?); with the nerves non-confluent. Palea present; relatively long; tightly clasped by the lemma; awnless, without apical setae; 2-nerved; 2-keeled. Ovary glabrous; without a conspicuous apical appendage.
Fruit, embryo and seedling. Fruit not grooved; smooth. Hilum short (?). Pericarp thin. Embryo small (?).
Special diagnostic feature. Female-fertile lemma not as in Lombardochloa (q.v.).
Taxonomy. Pooideae; Triticodae; Aveneae.
Distribution, ecology, phytogeography. 3 species (Clayton and Renvoize 1986); North and central America. Helophytic, or mesophytic; species of open habitats; glycophytic. Boggy meadows and moist ground, or montane.
Holarctic and Neotropical. Boreal and Madrean. Atlantic North American and Rocky Mountains. Caribbean.
References, etc. Morphological/taxonomic: Hitchcock and Chase (1950: Trisetum melicoides, T.wolfii); Clayton and Renvoize (1986).
Special comments. Description very inadequate. Fruit data wanting. Anatomical data wanting.
This description is offered for casual browsing only. We strongly advise against extracting comparative information from it. This is much more easily achieved using 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 specified attributes, summaries of attributes within groups of taxa, geographical distribution, classification, and species sampled for anatomy.
Cite this publication as: ‘Watson, L., 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: 18th December 2012. http://delta-intkey.com’.