The lithophyta are semi-aquatic green plants. They have large, branched thalli-like central stalk consisting of giant, multinucleated cells, with simple, scale-like microphylls leaves that have only a single vascular trace. The stalk grows from a a swollen base, attached in clusters to a bulb-like, underground rhizome or spreading mats, which contains the sproangia. Lithophyta reproduce by shedding spores and have macroscopic alternation of generations, although some are homosporous while others are heterosporous. Lithophytes get their classification from the silicate excretions they produce.