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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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.



Robert J. Soreng

Annual, perennial herb, some ± dioecious
Stem 0.3–12 dm
Leaf: sheath open to closed (best observed on upper stem leaf); ligule thin, flexible; blade grooved above on both sides of midvein, flat, folded, or inrolled, generally smooth or scabrous on veins, generally prow-tipped
Inflorescence panicle-like; branches appressed to drooping
Spikelet generally compressed, breaking between florets; glumes 2, similar, generally < lowest lemma, awnless; florets generally 2–6; callus indistinct, often with obvious tuft of long cobwebby hairs; lemma generally keeled to base, of same texture as glumes, awnless, veins generally 5, ± converging near tip; palea well developed, keels generally scabrous; fertile anthers 0.2–4.5 mm; ovary glabrous
Species in genus: ± 500 species: temp and cool regions
Etymology: (Greek: ancient name)
Reference: [Soreng 1991 Syst Bot 16:507–528]
CA is center of diversity in North America. Spikelet features best observed on lowest florets of spikelet.


P. cusickii Vasey

Perennial, ± densely cespitose, 1–6 dm, ± dioecious
Leaf: sheath open 1/5–3/4 length; ligule generally 1–6 mm (on sterile stems < 2 mm, truncate, scabrous); blade longest at mid-stem, on sterile stems generally 0.5–1 mm wide, ± firm, inrolled (sometime also folded), upper surface finely hairy
Inflorescence 2–12 cm, lanceolate to ovate, generally dense; branches ascending to appressed, slender, smooth or scabrous
Spikelet: callus generally glabrous; lemma keeled, generally glabrous (rarely keel sparsely hairy), smooth or scabrous; palea keels scabrous
Flower: fertile anthers 2–3.5 mm
Ecology: Moist to dry meadows, sagebrush scrub, montane forest
Elevation: 1500–3600 m.
Bioregional distribution: Klamath Ranges, High Sierra Nevada, Great Basin Floristic Province
Distribution outside California: to s Canada, ND, Colorado


subsp. cusickii

Leaves: basal tuft dense; sheath open 1/2–3/4 length; 0–1 nodes barely exposed
Inflorescence 3–12 cm; branches slender, obviously scabrous, longest generally > 17 mm
Spikelet: lemma 3.5–7.5 mm, glabrous or scabrous
Flower generally staminate or pistillate
Chromosomes: 2n=28
Ecology: Moist meadows, dry slopes in sagebrush scrub or montane forest
Elevation: 1500–2500 m.
Bioregional distribution: e Klamath Ranges, n High Sierra Nevada, Great Basin Floristic Province
Distribution outside California: to Washington, Idaho, n Nevada
Flowering time: May–Jul
Synonyms: P. hansenii Scribner
Horticultural information: IRR: 1, 2, 3.

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bioregional map for POA%20cusickii%20subsp.%20cusickii being generated
YOU CAN HELP US make sure that our distributional information is correct and current. If you know that a plant occurs in a wild, reproducing state in a Jepson bioregion NOT highlighted on the map, please contact us with that information. Please realize that we cannot incorporate range extensions without access to a voucher specimen, which should (ultimately) be deposited in an herbarium. You can send the pressed, dried collection (with complete locality information indicated) to us (e-mail us for details) or refer us to an accessioned herbarium specimen. Non-occurrence of a plant in an indicated area is difficult to document, but we will especially value your input on those types of possible errors (see automatic conversion of distribution data to maps).

Retrieve Jepson Interchange Index to Plant Names entry for Poa cusickii subsp. cusickii
Retrieve dichotomous key for Poa
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