Question
Select one of the following pairs of important features distinguishing Gnetum from Cycas and Pinus and showing affinities with angiosperms
Perianth and no integuments
Embryo development and apical meristem
Absence of resin duct and leaf venation
Presence of vessel elements and absence of archegonia
Solution
D.
Presence of vessel elements and absence of archegonia
Unlike Cycas and Pinus, Gnetum shows the occurrence of vessel elements and the complete absence of archegonia in female gametophyte. Thus, Gnetum shows affinities with angiosperms. Besides its resembles with angiosperms in several other aspects like presence of tetrasporic embryo sac, free nuclear divisions in the embryo sac, two cotyledonous embryo, etc
