Comparative Studies of Spermatogenesis in the Bryopsida. I. Blepharoplast Morphology in Funaria hygrometrica Hedw.

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Abstract
This report provides the first detailed analysis and graphic representation of blepharoplast morphology for a "true moss" (Bryopsida). Ultrastructural examination revealed that the spline of Funaria hygrometrica is unusual in having it''s anterior end longitudinally divided into two unequal portions, an effect of a transverse separation of approximately three microtubule-diameters in width between the fourth and fith microtubules from the spline''s right side. Because this slotlike separation is open at its proximal end, the term "open-aperturate" is used to distinguish it from the more common "closed-aperturate" spline in which the aperture is limited proximally by short microtubules. Closed-aperturate splines are common among hepatics and have also been reported in the mosses Polytrichum and Sphagnum. Among the hornworts, only inaperturate splines are known to occur. As in other bryophytes, the Funaria blepharoplast comprises two dimorphic basal bodies (BB) closely subtended by a multilayered structure (MLS) of four layers. The spline, which averages 13 microtubules at it''s widest region, is further characterized by having a single divergent microtubule along its left margin. This microtubule underlies the posterior BB for most of it''s length, rejoining the other spline microtubule near the level where the posterior flagellum emerges from the cell. The asymmetric lamellar strip is relatively small, about 0.5 .mu.m at its widest point and about 1.1 .mu.m in overall length. The BBs are unequal in length and staggered, the shorter anterior BB and the longer posterior one terminating about 0.2 and 0.5 .mu.m, respectively, behind the anterior margin of the spline.