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    Vascular Plants of California
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Limnobium spongia

Higher Taxonomy
Family: HydrocharitaceaeView DescriptionDichotomous Key

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: LimnobiumView Description 

Common Name: FROGBIT
Habit: 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.
Species In Genus: 2 species: America. Etymology: (Greek: living in pools)

Limnobium spongia (Bosc) Rich. ex Steud.
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.
Ecology: Streams, ponds, lagoons; Elevation: < 200 m. Bioregional Distribution: NCo, SnFrB; Distribution Outside California: southeastern United States, northern to New York. Flowering Time: Jun--Sep
Synonyms: Hydrocharis spongia Bosc; Limnobium laevigatum (Willd.) Heine, misappl.;
eFlora Treatment Author: Robert F. Thorne, C. Barre Hellquist & Robert R. Haynes
Jepson Online Interchange
Noxious Weed

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botanical illustration including Limnobium spongia


Citation for this treatment: Robert F. Thorne, C. Barre Hellquist & Robert R. Haynes 2012, Limnobium spongia, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on July 20, 2018.

Citation for the whole project: Jepson Flora Project (eds.) 2018, Jepson eFlora,, accessed on July 20, 2018.

Geographic subdivisions for Limnobium spongia:
NCo, SnFrB;
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.
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.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa, if there are more than 1 infraspecific taxon in CA.
Blue line denotes eFlora flowering time.