1) Gymnosperm 
The progymnosperms are an extinct group of woody, spore-bearing plants that is presumed to have evolved from the trimerophytes, and eventually gave rise to the gymnosperms. They have been treated formally at the rank of division Progymnospermophyta or class Progymnospermopsida (as opposite). The stratigraphically oldest known examples belong to th...
[n] - an ancestral fossil type from which modern gymnosperms are thought to have derived
noun an ancestral fossil type from which modern gymnosperms are thought to have derived