Wayne Armstrong's On-line Description of Wolffiella lingulata (Lemnaceae)
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Wolffiella lingulata

(C. Hegelmaier) C. Hegelmaier

Lingulate Mudmidget or Tongue-Shaped Mudmidget

Bot. Jahrb. 21: 303; 1895.


Roots: None

Shape of Plant Body: Flattened, broadly oblong and lingulate (tongue-shaped), concave dorsally (except in flowering plants) and with the free ends curved downward (recurved) into the water (often forming a semicircle when viewed laterally); flowering plants narrower and more flattened (not as concave and curved downward).

Size: 2-5 mm wide and 4-9 (10) mm long (generally 1.5 to 4 times as long as wide).

Veins: None in plant body; faint tract of elongated cells (costa) visible in budding pouch.

Budding Pouch Position: One flattened, triangular pouch at basal end; budding pouch angle 80-120 degrees; costa situated between middle and edge of lower wall of pouch; aerenchyma tissue (region of air spaces at basal end) usually not longer than wide.

Flower (Fruit) Position: Within floral cavity near basal end of dorsal surface, not enclosed by spathe; in flowering plants the basal end floats just at the water surface so that stamen and pistil are held above water.

Arrangement of Clonal Clusters: Solitary or 2-4 attached; when 2 attached, their recurved ends often form a circle when viewed from the side.

Habitat: Floating at surface or submersed in fresh water ponds, marshes and quiet streams, often beneath other Lemnaceae and aquatic plants.

Range: Scattered distribution in ponds and marshes at low elevations in coastal and interior valleys of central and northern California; unknown north of California; widespread in temperate and tropical regions of the western hemisphere, including the southeastern United States, Central and South America.

Other Information:

This sp. exhibits extreme morphological variation in California; under optimal growth conditions it may be identified by its broadly-lingulate, recurved plant body and wide budding pouch angle (generally greater than 85 degrees); smaller individuals growing under impoverished conditions greatly resemble W. oblonga (Phil.) Hegelm.; they may be distinguished by the angle of budding pouch and position of costa on lower wall of the pouch, ideally when viewed under a 30X microscope with substage illumination; this sp. possibly could survive in some of the mild valleys of coastal and interior Oregon; reported from coastal and interior valleys of southern California, but these populations are probably extirpated due to urbanization, flood control channelization and pollution.

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