Directory       News       Site Map       Home
         
    Jepson eFlora: Taxon page
Key to families | Table of families and genera

Previous taxon Indexes to all accepted names and synonyms:
| A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
Previous taxon

HYDROCHARITACEAE WATERWEED FAMILY

Robert F. Thorne, C. Barre Hellquist & Robert R. Haynes

Annual, perennial herb, aquatic, freshwater or marine, glabrous or hairy; monoecious, dioecious, or flowers bisexual. Leaf: basal, alternate, opposite, or whorled, generally sessile, generally ± sheathing at base. Inflorescence: axillary, terminal, or scapose, cyme or flowers 1, subtended by ± sheathing, entire or lobed bract; staminate flowers sometimes deciduous, free-floating. Flower: generally radial; perianth 0 or tube 0 or elongate, peduncle-like in flower; sepals (0)3(4), green; petals (0)3(4), white or not; stamens (0)2–many, generally in 1+ series; ovary inferior, chamber 1 or falsely 6–9, placentas parietal, ovules 1–many, style lobes generally 3, linear, lobed or notched. Fruit: achene or berry-like and dehiscing irregularly, linear to spheric, submersed.
± 17 genera, ± 130 species: worldwide; some cultivated for aquaria, others noxious weeds. [Haynes 2000 FNANM 22:26–38] Ottelia alismoides (L.) Pers. is a possibly extirpated alien. —Scientific Editor: Thomas J. Rosatti.
Unabridged references: [Les, D. H. [et al. 2006], Moody, M. L., & Soros, C. L. 2006. A reappraisal of phylogenetic relationships in the monocotyledon family Hydrocharitaceae (Alismatidae). Pp. 211–230, in Columbus, J. T., Friar, E. A., Porter, J. M., Prince, L. M., & Simpson, M. G. (eds), Monocots: Comparative Biology and Evolution. Excluding Poales. Rancho Santa Ana Botanical Garden, Claremont, Ca. [Aliso 22: 211–230.]; Tanaka, N., Uehara, K., & Murata, J. 2004. Correlation between pollen morphology and pollination mechanisms in the Hydrocharitaceae. J. Plant Res. 117:265–276]

Key to Hydrocharitaceae

NAJAS
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.
± 50 species: ± worldwide. (Greek: water nymph) [Haynes 2000 FNANM 22:77–83] Najas graminea Delile is an agricultural weed.
Unabridged references: [Shaffer-Fehre 1991 Bot J Linn Soc 107:189–209; Haynes 2000 FNANM 22:77–83]

Key to Najas

Previous taxon: Limnobium spongia
Next taxon: Najas flexilis

Contact/Feedback

Name search

Citation for the whole project: Jepson Flora Project (eds.) 2013. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on Oct 1 2014
Citation for this treatment: [Author of taxon treatment] 2013. Najas, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=9741, accessed on Oct 1 2014

Copyright © 2014 Regents of the University of California
We encourage links to these pages, but the content may not be downloaded for reposting, repackaging, redistributing, or sale in any form, without written permission from The Jepson Herbarium.


Markers link to CCH specimen records. If the markers are obscured, reload the page [or change window size and reload]. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.
READ ABOUT YELLOW FLAGS
map of distribution 1


View elevation by latitude chart
Data provided by the participants of the Consortium of California Herbaria.
View all CCH records