Abstract

RAMIREZ-VALENCIA, VALENTINA; SANIN, DAVID  and  PARDO-TRUJILLO, ANDRÉS. Morphological analysis of Serpocaulon (Polypodiaceae) spores from the Colombian Central cordillera. Caldasia [online]. 2013, vol.35, n.1, pp.177-197. ISSN 0366-5232.

Serpocaulon is a monophyletic genus within Polypodiaceae, comprised by 42 Neotropical species. The highest diversity of the taxa is found in northern South America, mainly in the Colombian Central Cordillera (21 taxa). Its infrageneric delimitation is still not precise because of a) nomenclatural problems, b) poor knowledge of their geographical distribution, c) high species diversity, and d) multiple hybridization events within the genus. In order to increase the taxonomic certainty of Serpocaulon, we described spores from all 21 taxa reported in the Colombian Central Andean Cordillera, using transmitted light-LTM and scanning electron-SEM microscopy. The analyzed specimens were obtained from several regional herbaria. For each species 25 spores were measured per view (lateral and proximal) and 15 morphological characters were evaluated. We used Principal Components Analysis (PCA) to determine taxa variability. Serpocaulon spores are monads, heteropolar, bilaterally symmetrical, ellipsoid, sub-ellipsoid to globular in proximal view, and plane-convex to concav-convex in lateral view. All studied taxa have verrucate ornamentation, which varies in size, shape, and distribution. Two basic types of perispores were recognized (thick-folded and thin-no folded). Our results suggest that the morphology of the verruca is important in determining most of the species and intrageneric definition. PCA was a useful technique to identify some morphological patterns. Finally, we present four morphological groups, which were suggested in previous molecular studies of Serpocaulon.

Keywords : Microscopy; monolete spores; verrucae; ferns taxonomy.

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