Wayne Armstrong's On-line Description of Lemna turionifera (Lemnaceae)
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Lemna turionifera

E. Landolt

Turion Duckweed

Aquatic Botany 1: 355; 1975.


Roots: One root.

Shape of Plant Body: Flattened, suborbicular to elliptic-obovate in outline, generally symmetrical; dorsal surface shiny dark green with row of minute papules along the midline.

Size: 2-4 mm long.

Veins: 3 veins (visible with backlighting).

Budding Pouch Position: 2 lateral pouches on either side of basal end.

Flower (Fruit) Position: Within membranous, saclike spathe (open only at top) inside budding pouches.

Arrangement of Clonal Clusters: Solitary or several (3-5) connected; producing small, rootless (or short-rooted), dark green or brownish daughter plants (turions) during the fall; the dense, starch-filled turions settle to the bottom and overwinter.

Habitat: Cold freshwater streams, ponds and marshes.

Range: Common throughout mountains and valleys of the Pacific Northwest, from sea level to 2500 m; widely distributed throughout the United States and Canada, and with isolated distribution in Russia in Asia.

Other Information:

The formation of dark green or brownish, starch-filled turions separates this sp. from all other Lemna spp. in North America; it is probably more widespread than the closely-related L. minor L.; it can be separated from L. minor by its turions, a pronounced dorsal midline row of papules, blotches of reddish anthocyanin that develop on the ventral side (especially near root base), and generally by a darker green dorsal surface; it can usually be separated from nongibbous forms of L. gibba L. by its turions, more symmetrical plant body (particularly at apex) and wingless utricles.

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