Fern plants. Like all other vascular plants, the diploid sporophyte is the dominant phase or generation in the life cycle. The gametophytes of ferns, however, are very different from those of seed plants. They are free-living and resemble liverworts, whereas those of seed plants develop within the spore wall and are dependent on the parent sporophyte for their nutrition. A fern gametophyte typically consists of: Ferns first appear in the fossil record in the early Carboniferous period. By the Triassic, the first evidence of ferns related to several modern families appeared. The great fern radiation occurred in the late Cretaceous, when
Dominant (music) B, and D. In music theory, the dominant triad (3-note chord) is a major triad, symbolized by the Roman numeral V, if it is within the major diatonic scale (for example G-B-D in C major). It is, however, a minor triad, denoted v, if it is within the minor diatonic scale (for example G-B-D in C minor). In the minor scale, the dominant triad is often substituted with a major triad, by sharpening the second note, which is a minor third from the dominant note, into a major third, since the major third from the dominant is the leading tone