Spore ultrastructure of <i>Orthotrichum affine</i> (type II).

<p>A–B: SEM, C–D: TEM. A) Subesphericall spore. Smooth perine elements cover the spore surface; some primary elements appear fused forming extensive bands throughout the spore (a feature common in type II morphotipes of this species). B) Detail of spore ornamentation showing smooth perine elements without secondary processes. C) General view of a spore, note the smooth perine and the fused primary elements in cross section. Exine thin, of uniform thickness, without polarization. Intine electrontranslucent, bilayered. Plastids well developed. Lipidic droplets abundant, most of them medium-electrondense and undissolved. D) Detail of a spore, note the continuous basal layer of perine connecting the primary elements and the bilayered structure of the intine, the outer layer compact, the inner layer thinner, fibrillar, lamellated. Abbreviations: bPe: basal layer of perine material; Chl: chloroplasts; dL: partially dissolved, electrondense lipidic droplets; dPe: detached perine elements; E: exine; fPe: fused perine elements; I: intine; Ie: external layer of the intine; Ii: internal layer of the intine; N: nucleus; Pe: perine elements; pg: plastoglobuli; sPe: perine secondary processes; S: starch grains, uL: undissolved, electron translucent lipid droplets.