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 visually very similar to dominant white. Dominant white is one of several potential genetic causes for horses with near-white or completely white coats; it may occur through spontaneous mutation, and thus may be found unexpectedly in any breed, even those that discourage excessive white markings. To date, dominant white has been identified in multiple families of Thoroughbreds, American Quarter Horses, Frederiksborg horses, Icelandic horses, Shetland ponies, Franches Montagnes horses, South German Draft horses, and in one family of the Arabian horse. The American White Horse, which is descended primarily from one dominant white stallion crossed on non-white mares, is known