Chromosome number and reproductive mode of some Pteris species (Pteridaceae) in Thailand
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Abstract
Abstract. Limpanasittichai P, Jaruwattanaphan T. 2022. Chromosome number and reproductive mode of some Pteris species (Pteridaceae) in Thailand. Biodiversitas 23: 3285-3296. The fern genus Pteris L. (Pteridaceae) consists of 329 species. This genus is one of the largest fern genera and is quite diverse with many different ploidy levels and reproductive modes resulting from complicated hybrid speciation events in their evolution. However, there have been very few observations of Pteridophytes in Thailand. This study aims to investigate chromosome number and reproductive mode of Pteris in Thailand. Mitotic chromosome numbers of 9 species collected from natural habitats were observed by hematoxylin squash method and their reproductive modes were estimated by counting the number of spores per sporangium. Three cytotypes were found, namely diploid, triploid and tetraploid. Nevertheless, only sexual individuals were recognized. First reports are provided for 3 species, namely P. dalhousieae (2n = 2x = 58, sexual), P. decrescens (2n = 2x = 58, sexual), and P. heteromorpha (2n = 2x = 58; 2n = 3x = 87 and 2n = 4x = 116, sexual) and the chromosome numbers from the remaining taxa match those reported from other countries. Two species, namely P. heteromorpha and P. vittata exhibited diverse cytotypes.