Most species extinct. Living ones are in warm climates. Once dominant plants, as tall as trees. Contributed to coal deposits Equisteum is the only living genus, grows in wet habitats. Outside China Garden True roots, stems, leaves.
Stems have silica, a good abrasive.
Club mosses are small with rhizomes underground and short, erect branches. Phylum Lycophyta Dominant in Carboniferous True roots, stems and microphyll leaves. Strobili on stems produce spores. The spores are high in an oil that is flammable and explosive, used in fireworks and gunpowder. More advanced plants are less dependent on water to transport reproductive cells.