THALLOPHYTA
Thallophyta
(noun) used only in former classifications: comprising what is now considered a heterogeneous assemblage of flowerless and seedless organisms: algae; bacteria; fungi; lichens
Source: WordNet® 3.1
Thal*loph"y*ta, n. pl. [NL. See Thallophyte.] (Bot.)
Definition: A phylum of plants of very diverse habit and structure,
including the algæ, fungi, and lichens. The simpler forms, as many
blue-green algæ, yeasts, etc., are unicellular and reproduce
vegetatively or by means of asexual spores; in the higher forms the
plant body is a thallus, which may be filamentous or may consist of
plates of cells; it is commonly undifferentiated into stem, leaves,
and roots, and shows no distinct tissue systems; the fronds of many
algæ, however, are modified to serve many of the functions of the
above-named organs. Both asexual and sexual reproduction, often of a
complex type, occur in these forms. The Thallophyta exist almost
exclusively as gametophytes, the sporophyte being absent or
rudimentary. By those who do not separate the Myxophyta from the
Tallophyta as a distinct phylum the latter is treated as the
lowermost group in the vegetable kingdom.
Source: Webster’s Unabridged Dictionary 1913 Edition