Spirodela

Schleiden

Linnaea 13: 391. 1839.

Common names: Duck-meal
Etymology: Greek speira, winding, and delos, distinct
Treatment appears in FNA Volume 22. Treatment on page 145.
 TaxonIllustrator 
FNA22 P27 Spirodela Lemna Wolffiella Wolffia pg 146.jpegLemna minor
Spirodela punctata
Lemna trisulca
Wolffia borealis
Lemna obscura
Wolffia arrhiza
Wolffia columbiana
Lemna minuta
Lemna perpusilla
Wolffiella gladiata
Spirodela polyrrhiza
Lemna turionifera
Lemna valdiviana
Wolffiella lingulata
Lemna gibba
Wolffia brasiliensis
Lemna aequinoctialis
Wolffiella oblonga
Wolffia globosa
John Myers
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John Myers
John Myers
John Myers

Roots (1–) 2–21 per frond, abaxial surface at node. Fronds floating (only turions sink to bottom), 2–10, coherent in groups, each obovate-circular, flat or gibbous, 1.5–10 mm, margins entire; air spaces in tissue; reproductive pouches 2, lateral, at base from which daughter fronds and flowers originate, triangular; veins (3–) 5–16 (–21), from point in proximal part of frond (node); small bifid 2-cleft membranous scale (interpreted as prophyllum) enveloping base of frond, covering point of attachment of roots; anthocyanins present (especially on abaxial surface); pigment cells present (visible in dead fronds as brown dots); turions present or absent, brownish olive, circular-reniform, smaller than growing frond. Flowers 1 (–2) per frond, surrounded by small utricular, membranous scale; stamens 2, 4-locular. Seeds 1–3, longitudinally ribbed. x = 10, 18, 23.

Distribution

Nearly worldwide

Discussion

Species 3 (2 in the flora).

Selected References

None.

Key

1 Fronds 1–1.5 times as long as wide, with 7–16(–21) veins and 7–21 roots, 1 or 2 perforating scale Spirodela polyrrhiza
1 Fronds 1.5–2 times, as long as wide, with (3–)5–7 veins and (1–)2–7(–12) roots, all perforating scale. Spirodela punctata
... more about "Spirodela"
Elias Landolt +
Schleiden +
small green +
Duck-meal +
Nearly worldwide +
Greek speira, winding, and delos, distinct +
coherent +
2 +  and 10 +
gibbous +, flat +  and obovate-circular +
0.15 cm1.5 mm <br />0.0015 m <br /> (1 cm10 mm <br />0.01 m <br />) +
not differentiated +
tapering +  and bottle--shaped +
membranous +
distinct +
funnel--shaped +
Spirodela +
Lemnaceae +
brownish olive +
circular-reniform +
smaller +
5 (?) +  and 16 (?) +
submersed +  and floating +
23 +, 18 +  and 10 +