Scientific name

Wolffiella Hegelm.

Common names

mud midget, bog mat



Could be confused with

Lemna, Wolffia

Native distribution

America, Asia, Africa

Species commonly cultivated

Wolffiella floridana (Donn. Sm.) C.H. Thomps. (southeastern North America)

W. gladiata (Hegelm.) Hegelm. (North America)

W. oblonga (Phil.) Hegelm. (America)

Adventive distribution

information not available

Weed status

information not available


free-floating, minute, thallus-like plant

Brief description

Minute, free-floating on or just below water surface, solitary or clumped. Reduced plant body, undifferentiated into stem and leaf. Roots absent. Fronds thin and ribbon-like, tongue shaped or broadly ovate, spherical to oblong, venation absent; margin entire. Daughter fronds in a flat pouch at one end of frond. Inflorescence minute, solitary or paired, of 1 female and 1 male flower. Flowers produced in budding pouch in middle of frond. Membranous spathe lacking. Dispersal by frond budding and seeds.

Natural habitat

still waters of lakes, rivers, and swamps

Additional comments

A genus containing 10 species. Three species are occasionally cultivated, although usually with difficulty, in aquaria and ponds.

An excellent resource for all Lemnaceae can be found at this website:

'Wayne Armstrong's treatment of the Lemnaceae'

A dichotomous key to the genera of Lemnaceae (source: Armstrong 2003):

1a. Plant body with 1 - several roots.

2a. Root one.......Lemna

2b. Roots 2 - 12.

3a. Roots 7 - 12 (or more); plant 10 mm long.......Spirodela

3b. Roots 2 - 3 (up to 5); plant 3 - 6 mm long.......Landoltia

1b. Plant body without roots.

4a. Plant body flattened; 3 - 10 mm long......Wolffiella

4b. Plant body globose-ovoid; 0.6 - 1.2 mm long.......Wolffia