Hornwort
Hornwort, any of a small class of green, flowerless plants that lack true roots, stems, and leaves. Hornworts are usually less than one-half inch (13 mm) in diameter. They are found in tropical, subtropical, and moist temperate regions, growing on moist ground or on other plants, such as trees. They are anchored by hairlike structures called rhizoids. Hornworts reproduce sexually by gametes and asexually by spores; they also reproduce by fragmentation, a process in which a part of the plant breaks off and grows into a new plant body.
Hornworts make up the class Anthocerotae.