Assertion : Conifer trees produce a large quantity of wind borne...

Conifer or Pinus is a heterosporous plant producing mega and microspores inside megasporangium and micro-sporangium respectively. Each microsporangium is a small, sessile and elongated sac like structure having two layered wall. Inside the wall lie tapetum which is a nourishing layer. Inside the cavity are large number of dusty and two winged microspores present. On maturity the microsporangium wall bursts from the upper side forming a longitudinal slit. A large number of yellow pollen grains are liberated which are carried by wind due to the presence of wings.