∞ generated and posted on 2016.08.30 ∞
Highly mobile embryonic sporophyte plant that is supported by previous-generation tissues.
Within a seed is grandparental sporophyte tissue, parental gametophyte tissue, and embryonic, that is, next-generation sporophyte tissue. This next-generation sporophyte association with the parental gametophyte is just as one sees in mosses. The association of gametophyte tissue with its parental sporophyte, however, is not a characteristic of mosses, but instead is seen only with seed-bearing plants, including gymnosperms such as pine trees along with the flowering plants (angiosperms).
Figure legend: Particularly as seen in gymnosperms, such as pines, the plant embryo within the seed is surrounded by parental gametophyte tissue, of maternal origin, which in turn is surrounded by grandparental sporophyte tissue, i.e., that of the conspicuous plant such as a pine tree's.
Note that not all seed-bearing plants are also fruit-bearing plants, though all non-sterile fruits also bear seeds. Note too that all seed-bearing plants are both vascular plants and plants that produce pollen, though not all vascular plants are seed bearing (e.g., ferns).