Habit: Annual, aquatic, submersed, mat-like or not; monoecious or dioecious.
Stem: several, often much-branched, slender.
Leaf: simple, cauline, +- opposite to +- whorled, sessile; sheath generally wider than, expanded abruptly at junction with blade; blade generally linear, margin entire to coarsely spine-toothed.
Inflorescence: axillary; flowers 1--few, clustered, inconspicuous.
Staminate Flower: subtended by (0)2 minute involucres, inner membranous, flask-shaped, outer cup-like, tubular, or with free scales; perianth 0; stamen 1, anther opening irregularly, subsessile.
Pistillate Flower: generally not subtended by involucres; perianth 0; ovary 1, chamber 1, ovule 1, style short, generally terminal (from center of ovary, fruit top), stigma 2--4-lobed.
Fruit: achene-like, fusiform; outer wall thin, +- translucent.
Species In Genus: +- 50 species: +- worldwide.
Etymology: (Greek: water nymph)
Note: Najas graminea Delile is an agricultural weed.
Jepson eFlora Author: Robert F. Thorne, C. Barre Hellquist & Robert R. Haynes
Reference: Haynes 2000 FNANM 22:77--83
Unabridged Reference: Shaffer-Fehre 1991 Bot J Linn Soc 107:189--209; Haynes 2000 FNANM 22:77--83Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)Key to Najas
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