Define Thallophyta.

Thallophyta is a botanical taxonomic division or phylum that was once used to classify certain groups of non-vascular plants characterized by their simple, undifferentiated body structure. Thallophyta included organisms that lack specialized tissues for conducting water, nutrients, and food, which are characteristic of higher plants. These plants typically have a thallus, which is a simple, flat, or branching structure that doesn't have roots, stems, or leaves.

Thallophyta was a traditional classification that encompassed various groups of lower plants, including algae, fungi, and some groups of non-vascular plants like liverworts. However, modern botanical taxonomy has evolved, and the classification system has been revised to reflect our improved understanding of plant relationships based on molecular and genetic data. As a result, Thallophyta is no longer considered a valid taxonomic division in contemporary botanical classifications. The organisms that were once classified under Thallophyta are now distributed among various other phyla and divisions in the plant kingdom.