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Type: Article
Published: 2017-07-21
Page range: 73–80
Abstract views: 24
PDF downloaded: 1

A new taxonomic treatment for the apogamous counterpart of Pteris terminalis (Pteridaceae)

Department of Botany, National Museum of Nature and Science, 4-1-1 Amakubo, Tsukuba 305-0005, Japan
Narahashi 1–363, Higashiyamato-shi, Tokyo 207–0031, Japan
Department of Horticulture, Faculty of Agriculture, Kasetsart University, 50 Ngamwongwan Rd., Ladyao, Jatujak, Bangkok 10900, Thailand
lectotype new combination Pteridophytes

Abstract

An Asia-Pacific fern species Pteris terminalis, formerly known as ‘Pteris excelsa’ is variable in terms of frond morphology as well as cytological characters. In particular, the results of previous cytological studies raised question on naturalness of currently accepted infraspecific taxa—‘P. excelsa var. simplicior’ (not yet combined with P. terminalis) consists of apogamous diploid and triploid, but these cytotypes are shared by the typical form of ‘P. excelsa’ (= P. terminalis), which is most widely distributed as sexual diploid. In the present study, the two varieties are re-circumscribed chiefly based on reproductive modes. Morphological characters including the length of apical pinna segments and the dissection degree of acroscopic side of pinna often, but not always, help their identification. After examination and lectotypification of type specimens of related taxa, correct names at varietal rank, two varieties P. terminalis var. terminalis and P. terminalis var. fauriei are proposed for the sexual form and the apogamous form, respectively.