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Najas graminea
RICE-FIELD WATER-NYMPH

Higher Taxonomy
Family: HydrocharitaceaeView DescriptionDichotomous Key

Common Name: WATERWEED FAMILY
Habit: 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.
Genera In Family: +- 17 genera, +- 130 species: worldwide; some cultivated for aquaria, others noxious weeds. Note: Ottelia alismoides (L.) Pers. is a possibly extirpated alien.
eFlora Treatment Author: Robert F. Thorne, C. Barre Hellquist & Robert R. Haynes
Scientific Editor: Thomas J. Rosatti.
Genus: NajasView DescriptionDichotomous Key

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.

Najas graminea Delile
AGRICULTURAL WEED
Habit: Monoecious. Stem: internodes not prickled. Leaf: margin teeth +- 40 per side, tip acute, with 2--3 teeth; sheath tip deep-lobed. Staminate Flower: 2--3 mm; anther chambers 4. Pistillate Flower: 1.5--3.5 mm; stigma 2-lobed. Seed: 0.4--0.6 mm wide, fusiform, coat pitted, dull. Chromosomes: 2n=24,36,48.
Ecology: Uncommon. Irrigation ditches, rice fields; Elevation: < 150 m. Bioregional Distribution: ScV (Butte, Colusa cos.); Distribution Outside California: Africa, Australia; native to tropical Asia. Flowering Time: Jun--Aug
eFlora Treatment Author: Robert F. Thorne, C. Barre Hellquist & Robert R. Haynes
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Citation for this treatment: Robert F. Thorne, C. Barre Hellquist & Robert R. Haynes 2016. Najas graminea, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=34353, accessed on September 24, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on September 24, 2016.


Geographic subdivisions for Najas graminea:
ScV (Butte, Colusa cos.);
Markers link to CCH specimen records. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues. Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
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map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).

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Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.