Calosteca Desv.
Including Calotheca P. Beauv.
Sometimes referred to Briza
Habit, vegetative morphology. Perennial (apparently); caespitose. Culms 40–80 cm high; herbaceous; unbranched above. Young shoots intravaginal. Leaves not basally aggregated; non-auriculate. Leaf blades linear; narrow; flat to folded; without cross venation; persistent; once-folded in bud; an unfringed membrane.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets; exposed-cleistogamous, or chasmogamous (?).
Inflorescence. Inflorescence paniculate; open; with capillary branchlets (?); espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.
Female-fertile spikelets. Spikelets 10–14 mm long; compressed laterally; disarticulating above the glumes; disarticulating between the florets; with conventional internode spacings. Rachilla prolonged beyond the uppermost female-fertile floret; the rachilla extension with incomplete florets. Hairy callus present.
Glumes two; more or less equal; shorter than the spikelets; shorter than the adjacent lemmas; hairless; awnless (to mucronate from a minutely bifid apex); non-carinate (?); similar. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets merely underdeveloped. Spikelets without proximal incomplete florets.
Female-fertile florets 5–10. Lemmas cuneate at the base, broad in the middle, narrowed to the apex; not becoming indurated; incised; 2 lobed; not deeply cleft (acuminate from the very broad base, but minutely incised at the tip); awned. Awns 1; median; from a sinus; non-geniculate; hairless; much shorter than the body of the lemma to about as long as the body of the lemma (2–5 mm long); entered by one vein. Lemmas non-carinate; without a germination flap; 7 nerved, or 9 nerved (?). Palea present; conspicuous but relatively short (lanceolate); entire; awnless, without apical setae (but with a conspicuous, hyaline, apical appendage); thinner than the lemma (membranous); not indurated; 2-nerved; 2-keeled (hairy between the keels). Palea keels narrowly winged. Lodicules present; 2; free; membranous; glabrous; toothed. Stamens 3 (presumably?). Ovary glabrous. Stigmas 2.
Fruit, embryo and seedling. Fruit small (about 2 mm long); trigonous. Hilum short. Embryo small. Endosperm hard.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous (the costal zones narrow). Papillae absent. Long-cells markedly different in shape costally and intercostally (the costals much shorter and narrower, with markedly sinuous walls). Mid-intercostal long-cells rectangular to fusiform (very long, minimizing the tendency to be fusiform); having straight or only gently undulating walls. Microhairs absent. Stomata absent or very rare (confined to short, discontinuous single files adjoining the costal zones). Subsidiaries parallel-sided. Guard-cells overlapped by the interstomatals (but only very slightly so). Intercostal short-cells absent or very rare. Costal short-cells neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies horizontally-elongated crenate/sinuous (crenate).
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll without adaxial palisade. Leaf blade with distinct, prominent adaxial ribs; with the ribs more or less constant in size (tall and narrow). Midrib somewhat conspicuous (with a larger rib); with one bundle only. The lamina symmetrical on either side of the midrib. Bulliforms present in discrete, regular adaxial groups; in simple fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders absent (all bundles with a small adaxial strand, the main bundles with an abaxial strand as well). Sclerenchyma all associated with vascular bundles.
Phytochemistry. Leaves without flavonoid sulphates (1 species).
Special diagnostic feature. Lemmas not as in Briza (q.v.).
Taxonomy. Pooideae; Poodae; Poeae.
Distribution, ecology, phytogeography. 1 species; South America.
Neotropical. Andean.
References, etc. Morphological/taxonomic: Mattei 1975, Nicora and Rúgolo de Agrasar 1981. Leaf anatomical: this project.
Special comments. Briza sect. Calotheca, Bromus brizoides.
Illustrations. • Leaf blade transverse section
Cite this publication as: Watson, L., and Dallwitz, M. J. (1992 onwards). ‘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.’ http://biodiversity.uno.edu/delta/. Version: 18th August 1999. Dallwitz (1980), Dallwitz, Paine and Zurcher (1993 onwards, 1998), and Watson and Dallwitz (1994), and Watson, Dallwitz, and Johnston (1986) should also be cited (see References).
