Microspore Wall Structure in Selaginella kraussiana (Lycophyta)

We have examined fresh and macerated microspores of Selaginella kraussiana (Kze.) A. Br. using scanning electron microscopy and chemically fixed spores prepared for transmission electron microscopy. These examinations indicated that the outer spiniferous part of the microspore wall (exospore) is composed of rods that are 70 to 130 nm in diameter and it has numerous conduits of variable size, that pass through the exospore. The structural rods of the exospore are deflected around the conduits. The inner part of the exospore has radial conduits (channels) and it has the same rod-structural units as the outer part. The spines on the outer exospore increase in number and size during development and develop many branches. The outer part of the exospore is separated from the inner part of the exospore by a gap