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 white white spotted coat. Dominant white is genetically distinct from Sabino and both genetically and visually distinct from gray and cremello. Dominant white is not the same as lethal white syndrome, nor are dominant white horses "albinos". Tyrosinase negative albinism has never been documented in horses. Some forms of dominant white are thought to result in nonviable embryos when a zygote has two "W" alleles (is homozygous). However, this has not been verified for all dominant white genetic variations. Dominant white horses are born with pink skin and a white coat, which they retain throughout their lives. Although the term "dominant