The grass genera of the world
Habit, vegetative morphology. Very diminutive alpine annual. Culms 0.3–1 cm high; herbaceous. Culm nodes hidden by leaf sheaths (the internodes condensed). Leaves non-auriculate. Sheaths green or hyaline, with broad membranous margins. Leaf blades linear to ovate; narrow (but relatively broad, and short); flat, or folded; without cross venation. Ligule present (lower leaves), or absent (upper leaves); an unfringed membrane; not truncate; 0.3 mm long.
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets. The spikelets all alike in sexuality.
Inflorescence. Inflorescence paniculate (usually shorter than the leaves); contracted; capitate (nearly concealed); espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.
Female-fertile spikelets. Spikelets 3–3.3 mm long; compressed laterally; disarticulating above the glumes. Rachilla terminated by a female-fertile floret. Hairy callus present, or absent.
Glumes two; more or less equal; shorter than the adjacent lemmas, or long relative to the adjacent lemmas; hairless; glabrous; pointed (apiculate, the apiculum sometimes recurved); awnless; carinate; very dissimilar to similar (membranous except along the vein, the lower sometimes apically lobed or shouldered). Lower glume 1 nerved. Upper glume 1 nerved. Spikelets with female-fertile florets only; without proximal incomplete florets.
Female-fertile florets 1. Lemmas similar in texture to the glumes (slightly firmer); not becoming indurated (membranous); entire; pointed; awnless (but apiculate), or mucronate (the awnlet less than 1mm long); uniformly hairy; non-carinate; without a germination flap; 1 nerved, or 3 nerved, or 5 nerved (sometimes with one or two pairs of short laterals); with the nerves non-confluent. Palea present; relatively long; awnless, without apical setae, or with apical setae (with one or two points, according to whether one or two veined); textured like the lemma; not indurated (membranous); 1-nerved, or 2-nerved; one-keeled (when 1 nerved), or keel-less. Palea back hairy. Lodicules present; 2; free; membranous; glabrous; toothed; not or scarcely vascularized. Stamens 2, or 3 (?). Anthers 0.4–0.6 mm long. Ovary apically glabrous. Styles free to their bases. Stigmas 2; white.
Fruit, embryo and seedling. Fruit free from both lemma and palea; small (1.5–1.7 mm long); pale brown; compressed dorsiventrally. Hilum short. Embryo small. Endosperm hard; with lipid; containing compound starch grains.
Abaxial leaf blade epidermis. Costal/intercostal zonation lacking. Papillae absent. Mid-intercostal long-cells fusiform; having straight or only gently undulating walls. Microhairs absent. Stomata common. Subsidiaries parallel-sided and dome-shaped. Intercostal short-cells common to absent or very rare; not paired (solitary); not silicified. Costal zones with short-cells (but few silica cells). Costal short-cells predominantly paired. Costal silica bodies not sharp-pointed.
Transverse section of leaf blade, physiology. C3; XyMS+. Leaf blade adaxially flat. Midrib not readily distinguishable; with one bundle only.
Classification. Watson & Dallwitz (1994): Pooideae; Poodae; Aveneae. Soreng et al. (2015): Pooideae; Poodae; Poeae; Poinae. 1 species (T. peruviana).
Distribution, phytogeography, ecology. Peru.
Species of open habitats. High Andes.
References, etc. Morphological/taxonomic: Macfarlane and But 1982. Leaf anatomical: Macfarlane and But 1982.
Illustrations. • Spikelet details: Macfarlane & But, 1982
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’.