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Previous taxon Indexes to all accepted names and synonyms:
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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

Perennial herb, floating in dense mats, rooted in mud when stranded; monoecious. Stem: stolons floating or suspended in water. Leaf: basal, emergent or floating, petioled; floating with swollen spongy cells abaxially. Inflorescence: cyme, peduncle 0 or short. Flower: unisexual, emergent, pedicelled; petals green-white to yellow. Staminate flower: filaments fused at least 1/2, anthers elongate. Pistillate flower: ovary chambers 1, styles 3–9, 2-lobed ± to base. Fruit: fleshy berry, ellipsoid to spheric, smooth to ridged, dehiscing irregularly. Seed: ellipsoid, spiny.
2 species: America. (Greek: living in pools)

L. spongia (Bosc) Steud. AMERICAN FROGBIT
Leaf: 1–10 cm, 0.9–7.8 cm wide; petioles to 15 cm; blades ovate to ± round, bases reniform to cordate. Flower: sepals 3; petals 3. Staminate flower: stamens 9–12(18), filaments fused into column, anthers 6–12. Pistillate flower: stigmas 6–18. Fruit: 4–12 mm diam.
Streams, ponds, lagoons; < 200 m. North Coast, San Francisco Bay Area; southeastern United States, northern to New York. [Limnobium laevigatum (Willd.) Heine, misappl.] Jun–Sep {Noxious weed} [Online Interchange]
Unabridged note: Expanded author citation: Limnobium spongia (Bosc) Rich. ex Steud.

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Citation for the whole project: Jepson Flora Project (eds.) 2013. Jepson eFlora,, accessed on Mar 29 2015
Citation for this treatment: [Author of taxon treatment] 2013. Limnobium, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on Mar 29 2015

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Geographic subdivisions indicated for the distribution of Limnobium spongia 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.
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.