The thallose liverworts that have been most heavily researched belong to the genus Marchantia, which are commonly found among moist soils in the Northern Hemisphere. In their sexual stage, these plants are dark green, dichotomously branched, and ribbon-like, typically growing about a half-inch wide and several inches long. When they are sexually mature, they may either grow small umbrella-shaped male reproductive organs, known as antheridiophores, or female archegoniophores, the shape of which is reminiscent of miniature palm trees. When it rains, the antheridia located on an antheridiophore begin to generate sperm, which are able to swim to the female archegonia, which are situate along the head of the archegoniophore, where fertilization ensues.