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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 2016. Limnobium spongia, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on May 02, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora,, accessed on May 02, 2016.

Geographic subdivisions for Limnobium spongia:
NCo, SnFrB;
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.