Jepson eFlora: Taxon page
Key to families | Table of families and genera
Previous taxon Index to 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 |
Next taxon
Hydrilla verticillata

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: HydrillaView Description 


Species In Genus: 1 sp. Etymology: (Greek: in water)

Hydrilla verticillata (L. f.) Royle
NATURALIZED
Habit: Perennial herb, rooting at nodes, submersed; dioecious. Stem: tuber-like; erect stems elongate, much-branched. Leaf: generally 4--8 per node, sessile, 1--2 cm, 1.5--2 mm wide, oblong, coarsely serrate, midrib prickled abaxially or not, tip generally sharp-pointed. Staminate Inflorescence: flower 1, bract at base of elongate perianth tube, spheric. Pistillate Inflorescence: flower 1, bract at base of elongate perianth tube, +- cylindric. Staminate Flower: deciduous, free-floating; perianth parts 6 in 2 whorls, 3--5 mm; stamens 3. Pistillate Flower: persistent, floating; perianth parts 6 in 2 whorls, 3--5 mm; stigmas 3. Fruit: 5--6 mm, +- fusiform. Chromosomes: 2n=32.
Ecology: Canals, ponds, lakes; Elevation: < 200 m. Bioregional Distribution: NCoRI, n&c SNF, ScV, SCo, D; Distribution Outside California: southeastern and eastern United States, Central America; native to Eurasia, Australia. Flowering Time: Jun--Aug
eFlora Treatment Author: Robert F. Thorne, C. Barre Hellquist & Robert R. Haynes
Jepson Online Interchange
Noxious Weed

Previous taxon: Hydrilla
Next taxon: Limnobium

Name Search
botanical illustration including Hydrilla verticillata

Contact/Feedback

Citation for this treatment: Robert F. Thorne, C. Barre Hellquist & Robert R. Haynes 2016. Hydrilla verticillata, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=28595, accessed on September 30, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on September 30, 2016.


Geographic subdivisions for Hydrilla verticillata:
NCoRI, n&c SNF, ScV, SCo, D;
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.
READ ABOUT YELLOW FLAGS
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).

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

CCH collections by month

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