A phylogenetic classification of ophioglossaceae
1987
Kato, M. (University of Tokyo, Nikko (Japan). Faculty of Science)
A cladistic approach was undertaken to construct a phylogenetic classification of the Ophioglossaceae. The characters used are: rhizome, stele, leaf sheath, size and cutting of trophophyll, vascular branching in leaf axes, venation, position of sporophyll on trophophyll, form and construction of sporophyll, position and dehiscence of sporangia, and suspensor. Character state, primitive (plesiomorphic) vs. advanced (apomorphic), was estimated for each character. Based on presume character phylogenies, a cladogram representing phylogenetic relationships was drawn. Although in previous classifications (e.g. Clausen, 1938) the Ophioglossaceae were classified into three genera, Botrychium, Helminthostachys and Ophioglossum, it is contended here that the genus Botrychium sensu Clausen is not a monophyletic group. In this paper I propose a new classification recognizing six genera and arrange them as in Cracraft's (1974) sequence as follows: 1 (most primitive), Botrypus; 2, Japanobotrychium; 3-1, Sceptridium; 3-2, Helminthostachys; 4, Botrychium; 5 (most advanced), Ophioglossum
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