Wolffia arrhiza
Fl. Schles., ed. 3 140. 1857.
WeedyIntroducedIllustrated
Basionym: Lemna arrhiza Linnaeus Mant. Pl. 2: 294. 1771
Treatment appears in FNA Volume 22. Treatment on page 152.
Fronds globular to ovoid, 0.5–1.5 mm, 1–1.3 times as long as wide, 1.2–1.5 times as deep as wide, slightly pointed at apex, papilla absent; upper surface intensely green (not transparent), with 10–100 stomates; pigment cells absent in vegetative tissue. 2n = 30, 40, 42, 44–46, 50, 60, 62 (Europe, Africa).
Phenology: Flowering (very rare) late spring–summer.
Habitat: Mesotrophic to eutrophic, quiet waters in temperate to subtropical regions with relatively mild winters
Elevation: 0–800 m
Distribution
Introduced; Calif., South America (Brazil), w Eurasia, Africa
Discussion
Wolffia arrhiza was reported from Alberta because of the size of epidermal cells (G. C. D. Griffiths 1988). The plants are within the variation shown by W. columbiana, however.
Selected References
None.
Lower Taxa
None.
"-1.5timesasdeepaswide" is not declared as a valid unit of measurement for this property.
... more about "Wolffia arrhiza"
absent +
absent +
small green +
absent +
pigment +
absent +
bisexual +
coherent +
1-1.3 +
arising +
not differentiated +
Mesotrophic to eutrophic, quiet waters in temperate to subtropical regions with relatively mild winters +
Present +
true +
branching +
absent +
membranous +
absent +
Fl. Schles., ed. 3 +
1857 +
absent +
absent +
1;21 +
absent +
distinct +
absent +
funnel--shaped +
10;100 +
Wolffia arrhiza +
Wolffia +
species +
vegetative +
light green +
globular +
smaller +
absent +
absent +
perennial +
reduced +