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Wolffia columbiana

Higher Taxonomy
Family: AraceaeView DescriptionDichotomous Key

Common Name: ARUM FAMILY
Habit: Perennial herb, [shrub, vine], terrestrial [growing on other plants or not], or aquatic, sometimes free-floating, then sometimes much reduced, in dense, clonal populations, 0.4--10 mm, flat and tongue-shaped to spheric, not differentiated into stems and leaves, new plants produced in budding pouch at base or along margins, sometimes overwintering on bottom as dense, rootless, starch-filled daughter plant (winter bud); often from short, generally erect caudex; roots 0--many; often monoecious. Stem: sometimes above ground in addition to caudex, or not differentiated from plant body. Leaf: simple or compound, basal (or cauline, 2-ranked), or not differentiated from plant body. Inflorescence: generally spike, fleshy, generally ill-smelling, or flower 1, rarely seen, minute, appearing like 2--3 unisexual flowers, often sheathed by minute membrane; flowers bisexual or pistillate below, staminate above; bract subtending spike 1, generally showy (petal-like), generally > spike, sheathing or not. Flower: perianth parts 0, 4, 6, free or fused; stamens 0--4, 6, free or fused; ovary superior to 1/2-inferior and sunken in inflorescence axis, chambers 1--3, stigma +- sessile. Fruit: berry or achene-like, winged or not. Seed: 1--many, often ribbed.
Genera In Family: +- 114 genera, 1850 species: generally tropics, subtropics some cultivated for food, ornamental in ponds, aquaria (Colocasia, taro) or ornamental (Philodendron, Anthurium). Note: Since TJM (1993), including Lemnaceae, and except Acorus, now in Acoraceae (the sole member in California, Acorus calamus L., is an historical waif). Pistia stratiotes L. is a waif. Pinellia ternata (Thunb.) Breitenbach possibly naturalized in California. In taxa once included in Lemnaceae, vein number per plant body best determined using backlight.
Unabridged Note: Since TJM (1993), including Lemnaceae, except Acorus, now in Acoraceae (the sole representative of the family in California, Acorus calamus, judged to be an historical waif in California and therefore here except). Incl smallest of all known angiosperms (Wolffia globosa) as well as world's most massive inflorescence (spike of Amorphophallus titanum, Titan Arum, to 4 m in circumference). Needle-like crystals in most tissues cause intense irritation when chewed; those of Dieffenbachia, dumb-cane, may induce temporary speechlessness. Incl of fossil evidence in cladistic analyses indicate Lemnaceae and Pistia form a monophyletic group within Araceae (Stockey et al.), a position now generally accepted (see Les et al.). Pinellia ternata (Thunb.) Makino ex Breitenbach introduced, possibly naturalized in California. Taxa formerly included in Lemnaceae may be very invasive. In taxa formerly included in Lemnaceae, vein number per plant body best determined using backlight. Peltandra virginica (L.) Schott & Endl., included in TJM (1993), reportedly spread from ornamental pool introduction in 1970 to nearby reserviors, but degree of reproduction or even persistence there unknown.
eFlora Treatment Author: Thomas J. Rosatti, except as noted
Scientific Editor: Bruce G. Baldwin, Thomas J. Rosatti.
Genus: WolffiaView DescriptionDichotomous Key

Common Name: WATERMEAL
Habit: Plants much reduced, not differentiated into stems, leaves; floating aquatics; roots 0. Plant Body: generally in unequal 2s; 0.4--1.3 mm, +- cylindric to nearly spheric, floating on or partially below water surface; veins 0; budding pouch funnel-shaped; winter buds often produced. Flower: produced in cavity on upper surface; sheathing membrane 0; stamen 1; pistil 1. Seed: smooth.
Species In Genus: 11 species: worldwide, especially temperate, tropics. Etymology: (J.F. Wolff, German botanist, physician, 1778--1806) Note: Key for use at > 10×.
eFlora Treatment Author: Wayne P. Armstrong

Wolffia columbiana H. Karst.
NATIVE
Plant Body: 0.8--1.3 mm, +- spheric, transparent green, upper surface mostly convex, center flat, floating above water, stomates 1--10(30), tip round.
Ecology: Freshwater; Elevation: < 200 m. Bioregional Distribution: SnJV, CCo, SnFrB, SCoRO, SCo; Distribution Outside California: to Canada, South America. Flowering Time: Summer--fall Note: Small plants much like Wolffia globosa.
eFlora Treatment Author: Wayne P. Armstrong
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botanical illustration including Wolffia columbiana

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Citation for this treatment: Wayne P. Armstrong 2016. Wolffia columbiana, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=48590, accessed on May 05, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on May 05, 2016.


Geographic subdivisions for Wolffia columbiana:
SnJV, CCo, SnFrB, SCoRO, SCo;
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.
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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.