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

DUCKWEED FAMILY

Wayne P. Armstrong

Perennial, floating aquatics, small, clonal, in dense populations; new plants produced in budding pouch at base or along margins; may overwinter on bottom as dense, rootless, starch-filled daughter plant (winter bud); roots 0–many
Plant body 0.4–10 mm, flat and tongue-shaped to spheric
Flower 1, rarely seen, minute, appearing like 2–3 unisexual flowers, often sheathed by minute membrane; perianth 0; stamens 1–2; pistil 1, simple, maturing before stamens
Fruit achene-like, sometimes winged
Seeds 1–3, smooth or ribbed. Spp. best separated by chemistry and fruit; clones vary; magnification, backlighting generally needed to identify vegetative plants
Genera in family: 4 genera, 34 species: worldwide; ornamental in pools, aquaria
Reference: [Landolt 1986 Veröff Geobot Inst ETH Stiftung Rübel Zürich 71]
Horticultural information: TRY.

LEMNA

DUCKWEED

Plants generally in clusters of 2–many; root generally 1, generally 2–6 mm, sheath near base generally not winged
Plant body generally 2–5 mm, flat, generally widely elliptic to oblong, pale to dark green, often ± red; veins 1–5 (visible in backlight); winter buds generally 0
Flowers in 2 lateral pouches, sheathed by minute membrane
Fruit generally unwinged
Seed ribbed, generally smooth between ribs
Species in genus: 13 species: worldwide
Etymology: (Greek: lake or swamp)

Native

L. minuta Kunth


Plant bodies generally in pairs (especially when crowded, in full sunlight), 1–2.5 mm, widely elliptic to oblong, pale green; base and tip generally symmetric; margin clearly thinner than center; vein 1, obscure, < 2/3 distance from root node to tip of plant body (generally < region of visible air spaces between cells)
Seed cross-lined between ribs
Ecology: Common. Freshwater
Elevation: < 2200 m.
Bioregional distribution: California (except Modoc Plateau)
Distribution outside California: w US, S.America, Europe, n Asia
Flowering time: Aug
Transparent green plants, 2–4 mm, in 4's, are much like L. valdiviana
Synonyms: L. minima Hegelm., L. minuscula Herter
Needs study.

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bioregional map for LEMNA%20minuta 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 Lemna minuta
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