Thallophyta

[Sarah]

A phylum of plants of very diverse habit and structure,including the algæ, fungi, and lichens. The simpler forms, as manyblue-green algæ, yeasts, etc., are unicellular and reproducevegetatively or by means of asexual spores; in the higher forms theplant body is a thallus, which may be filamentous or may consist ofplates of cells; it is commonly undifferentiated into stem, leaves,and roots, and shows no distinct tissue systems; the fronds of manyalgæ, however, are modified to serve many of the functions of theabove-named organs. Both asexual and sexual reproduction, often of acomplex type, occur in these forms. The Thallophyta exist almostexclusively as gametophytes, the sporophyte being absent orrudimentary. By those who do not separate the Myxophyta from theTallophyta as a distinct phylum the latter is treated as thelowermost group in the vegetable kingdom.