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SHEFFIELD, E., WOLF, P. G., HAUFLER, C. H., RANKER, T. A. & JERMY, A. C, 1989. Are‐evaluation of plants referred to as Pteridiutn herediae (Colmeiro) Love & Kjellqvist. Based on perceived differences in morphology, chromosome number and habitat, specimens of Pteridiutn from southern Spain have been segregated by previous authors as a species distinct from Pteridium aquilinum, and called Pteridium herediae. However, type specimens of this taxon cannot be found. New collections of Pteridium from similar habitats in the area were examined and analysed in the present study and the results compared with those from British plants (P. aquilinum). The Spanish plants were not found to differ significantly from P. aquilinum morphologically, and all yielded chromosome counts (sporophytes, 104; gametophytes, 52) considered typical for the genus. Genotype frequency data obtained from isozyme electrophoresis of Spanish and British Pteridium yielded a genetic identity of 0.86; well within intraspecific distances found in other ferns. These data indicate that there are currently no grounds for accepting that a form of Pteridium, distinguishable from P. aquilinum on the basis of differences in morphology, chromosome number, habitat or biochemistry, exists on the limestone soils of the Sierra de Cazorla region of southern Spain.

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There are surface coats on the sporocytes and spores of some pteridophytes and bryophytes which will bind one or more of the stains generally used to demonstrate the presence of an acid mucopolysaccharide surface coat in animal cells, viz. Alcian blue, colloidal iron, lanthanum, thorium, silver, SO,‐coriphosphine and phosphotungstic acid. This suggests that the composition of the coat substances in the ferns and bryophytes agrees with that in animal cells. It has been found that thorium‐staining in the sporocyte and the coat of the young spore of one fern, Botrychium lunaria, can be abolished with neuraminidase, indicating that sialic acid is a principal component of these coats. The spore wall in the pteridophytes (and probably also in the bryophytes) is constructed within these mucopolysaccharide surface coats, and it is suggested that differences in wall form are attributable to qualitative, quantitative and functional differences of the coats.