Spore morphology and ultrastructure of the tropical moss Helicophyllum torquatum (Hook.) Brid. (Helicophyllaceae) in relation to systematics and evolution

Spores of Helicophyllum torquatum (Hook.) Brid. (Helicophyllaceae, a monotypic family of tropical mosses) were studied by means of TEM, SEM, and LM. Different techniques of staining were employed to reveal the sporoderm structure. The spores are isomorphic, medium-sized (ranging from 26.40 to 41.80 µm), heteropolar, subcircular amb, plane-convex, catatremate, the surface consists of granules and gemmae. The systematic significance of spore morphology of this species are being considered here for the first time. Spore characteristics are congruent with the hypothesis of an affinity of the Helicophyllaceae with acrocarpous lineages.