Comparative Studies of Spermatogenesis in the Bryopsida. III. Blepharoplast Morphology in Thuidium delicatulum

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Abstract
Ultrastructural observations of the spermatids of Thuidium delicatulum reveal a blepharoplast comprising a multilayered structure of the typical four-layered type and two superposed, overlapping basal bodies. The longitudinally elongated lamellar strip is approximately rhomboidal, 2.6 .mu.m long and 0.5 .mu.m wide. Most commonly, the spline comprises 14 microtubules at its widest region. These are separated into two sets (10 at left and four at right) by a 3 .mu.m long aperture of the open type. The aperture is three microtubule-diameters wide along its midregion, narrowing to only one at its anterior end. The anterior basal body is 2.1 .mu.m long and lies directly above and parallel to the spline aperture. The posterior basal body is 7.0 .mu.m long and diverges posteriorly in association with the left marginal microtubule of the spline. The stellate patterns, each measuring 46 nm in length, are the shortest reported for any bryophyte. Although differing substantially in lamellar strip morphology and overall dimensions, the blepharoplast of Thuidium shares more features with that of Funaria than with those of Archidium, Polytrichum or Sphagnum.