Q. What is the earliest evolving seed plant that survives today?
Conifers and other gymnosperms are the oldest seed plants still extant today. According to the fossil record they evolved about 300 million years ago and have diverged into a diverse group of cone-bearing plants (cedars, cypresses, firs, junipers, pines, hemlocks, spruces and yews) which survive today. Conifers differ from flowering plants (Angiosperms) in that their seeds are naked (lacking a coat).
Flowering plants did not evolve until about 150 million years ago. Among existing flowering plants, the family Amborellaceae, of which Amborella trichopoda is the only extant species, is considered to be at the base of the flowering plant lineage, Amborella iis a small shrub confined to the island of New Caledonia in the Pacific Ocean. Among characteristics that make it primitive is the nature of its wood - it has no vessels and consists only of tracheids. Other characteristics are simple, separate flower parts of indefinite number and unsealed carpels
New Caledonia is clearly proud of this plant as it appears on one of its postage stamps.
Courtesy of NYBG Plant Information