Jepson Flora Project: Jepson Interchange    

 
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Jepson Interchange (more information)
©Copyright 1993 by the Regents of the University of California
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AZOLLACEAE

MOSQUITO FERN FAMILY

Alan R. Smith

Plant free-floating or stranded on mud, generally 1–5 cm, often fan-shaped; roots pendent from stem forks, unbranched
Stem forked repeatedly or pinnate, thread-like, easily fragmented at joints
Leaves alternate, in 2 rows, sessile, often overlapped, 0.5–1.5 mm, seemingly paired but actually of 2 roundish to ovate lobes; upper lobe floating or emergent, thick, greenish or reddish, margin whitish; lower lobe submersed, generally slightly larger, thinner, whitish
Sporangia in seemingly axillary cases of 2 kinds, cases generally in pairs of 1 kind
Male sporangium case 1.2–2 mm diam, spheric; tip dark-pointed; wall transparent; sporangia generally 20–100+, long-stalked; spores 32 or 64, spheric, in generally 3–6 barbed masses
Female sporangium case 0.2–0.4 mm diam, hemispheric or spheric; tip obtuse, covered by dark, conic, spongy structures that aid in flotation; wall ± opaque; sporangium 1, sessile; spore 1, spheric
Genera in family: 1 genus, ± 7 species: ± worldwide. Salvinia molesta D.S. Mitch. has been tentatively identified from Walter's Camp, Imperial Co.; more study needed.

AZOLLA


Etymology: (Greek: dry kill, from plant death in dried habitats)
Reference: [Perkins et al. 1985 Scanning Electron Microscopy 1985(IV):1719–1734]
Used as green manure in rice paddies because of nitrogen-fixing algae in upper leaf lobe; species identification requires generally female sporangium cases (generally 0 on herbarium specimens), often leaf sectioning, compound microscope.

Native

A. filiculoides Lam.

Plant green to reddish, fertile only when ascending
Stems < 5+ cm: immature prostrate, internodes < 5 mm; mature ascending, internodes < 1 mm
Sporangium cases generally male
Ecology: Common. Ponds, slow streams, wet ditches
Elevation: 0–1600 m.
Bioregional distribution: California Floristic Province, Great Basin Floristic Province
Distribution outside California: to Washington, Arizona, S.America, Eurasia, Africa; also e US
Horticultural information: still water [not saline] or mud: 4, 5, 6, 7, 8, 9, 10, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24.

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bioregional map for AZOLLA%20filiculoides being generated
 
N.B. The distribution depicted here differs from that given in The Jepson Manual (1993)
YOU CAN HELP US make sure that our distributional information is correct and current. If you know that a plant occurs in a wild, reproducing state in a Jepson bioregion NOT highlighted on the map, please contact us with that information. Please realize that we cannot incorporate range extensions without access to a voucher specimen, which should (ultimately) be deposited in an herbarium. You can send the pressed, dried collection (with complete locality information indicated) to us (e-mail us for details) or refer us to an accessioned herbarium specimen. Non-occurrence of a plant in an indicated area is difficult to document, but we will especially value your input on those types of possible errors (see automatic conversion of distribution data to maps).

Retrieve Jepson Interchange Index to Plant Names entry for Azolla filiculoides
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Overlay Consortium of California Herbaria specimen data by county on this map
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