Jepson Flora Project: Jepson Interchange    

 
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Jepson Interchange (more information)
©Copyright 1993 by the Regents of the University of California

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POACEAE

GRASS FAMILY

James P. Smith, Jr., except as specified

Annual to bamboo-like; roots generally fibrous
Stem generally round, hollow; nodes swollen, solid
Leaves alternate, 2-ranked, generally linear; sheath generally open; ligule membranous or hairy, at blade base
Inflorescence various (of generally many spikelets)
Spikelet: glumes generally 2; florets (lemma, palea, flower) 1–many; lemma generally membranous, sometimes glume-like; palea generally ± transparent, ± enclosed by lemma
Flower generally bisexual, minute; stamens generally 3; stigmas generally 2, generally plumose
Fruit: achene-like grain
Genera in family: 650–900 genera; ± 10,000 species: worldwide; greatest economic importance of any family (wheat, rice, maize, millet, sorghum, sugar cane, forage crops, ornamental, weeds; thatching, weaving, building materials)
Reference: [Hitchcock 1951 Manual grasses US, USDA Misc Publ 200; Clayton & Renvoise 1986 Kew Bull Add Series 13]
See Glossary p. 26 for illustrations of general family characteristics. Generally wind-pollinated.

PIPTATHERUM

Mary E. Barkworth

Perennial, cespitose
Stem erect, unbranched
Leaf: ligule membranous, generally truncate; blade flat to inrolled, often tapered
Spikelet: glumes ± equal, obtuse to acute, veins evident; axis breaking above glumes; floret 1, generally ± compressed; callus blunt; lemma margins widely separated with age, awn generally readily deciduous; palea ± = lemma, texture like lemma
Species in genus: 30 species: arid temp, subtropical Eurasia, Africa
Etymology: (Greek: falling awn)
Segregated from Oryzopsis.

Native

P. micranthum (Trin. & Rupr.) Barkworth

SMALL-FLOWERED RICEGRASS


Stem 3–6.5 dm
Leaf: basal ligule 0.4–1.5 mm
Inflorescence 8–13 cm; lowest branches becoming reflexed
Spikelet: glumes 2.5–3.5 mm; floret 1.5–2.5 mm; lemma generally glabrous, sometimes sparsely but evenly short-hairy, awn 4–8 mm, weakly bent
Chromosomes: 2n=22
Ecology: Gravel benches, rocky slopes, creek banks
Elevation: 700–2950 m.
Bioregional distribution: White and Inyo Mountains, Desert Mountains
Distribution outside California: to British Columbia, Rocky Mtns
Flowering time: Jun–Sep
Synonyms: Oryzopsis m. (Trin. & Rupr.) Thurb
See the CNPS Inventory for information about endangerment and rarity.
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bioregional map for PIPTATHERUM%20micranthum being generated
 


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