On-Line Key to the Genus Wolffia
Home Keys To Genera List Of Species Search Lemna Spirodela Wolffia Wolffiella Wayne's Word
Zoom In With Large, High Res Monitors:   For PCs type Control +  For Macs type Command +


Genus: Wolffia

Keys To This Genus

Plant bodies minute and rootless, with granular or mealy texture when rubbed between fingers of hands; generally globoid to ovoid-ellipsoid or cylindrical (flat-topped in some species); 0.4-1.3 mm long and 0.2-1.0 mm wide, floating on or partially below water surface; veins 0; pale transparent green throughout or with dark green dorsal surface; some species punctate with brown pigment cells in epidermis (visible on dead plants of W. borealis & W. brasiliensis); solitary or with smaller daughter plant attached at basal end; single, funnel-shaped budding pouch at basal end; daughter plants produced in basal budding pouch (in most species, some daughter plants may sink to bottom and function as overwintering turions); parenchyma without druse or raphide crystals of calcium oxalate; one bisexual flower produced inside dorsal floral cavity, consisting of a single pistil and single stamen (some authorities consider this to be an inflorescence with 2 unisexual flowers); pistil situated nearest the basal budding pouch; anther unilocular and apically dehiscent along pigmented line; ovary unilocular with one orthotropous ovule; utricle globose and slightly compressed, bearing 1 globose-ovoid, smooth seed with distinct conical operculum (seed may be slightly reticulate but not longitudinally ribbed); size and shape of plant body important for species identification (ideally under 10-20X magnification); at least 9 spp. worldwide, especially warm temperate and tropical regions; J.F. Wolff, German botanist and physician, 1778-1806; Armstrong, W.P. & R.F. Thorne (1984), Madrono 31: 172-179; Armstrong, W.P. (1989), Madrono 36: 283-285; Armstrong, W.P. (1985), Fremontia 13: 11-14.

From here you can access:

  • Keys to this genus

  • Images of some species of Wolffia

Return To The Lemnaceae Home Page
Go To Keys To The Genera Of Lemnaceae
Go To The List Of Species Of Lemnaceae
Go To The List Of .GIF Images Of Lemnaceae
Go To The WAYNE'S WORD Home Page