A CLADISTIC-ANALYSIS OF GERANIUM SUBGEN ERODIOIDEA (PICARD) YEO (GERANIACEAE)

Subgenus Erodioidea, comprising 19 species, is diagnosed exclusively b y the type of fruit discharge and associated morphological characters, all of which are of widespread occurrence within the Geraniaceae. We have no evidence to suggest that the three included sections (Erodioid ea, Aculeolata and Subacaulia) form a monophyletic group. Cladistic an alysis of a data set containing 30 morphological characters has confir med our doubts of monophyly of the subgenus by placing part of the out group within the ingroup. Subsequent analyses of the two included non- monotypic sections, Erodioidea and Subacaulia, give different results. For both sections, the monophyly assumption is reasonably well-suppor ted by characters. However, while analysis of sect. Erodioidea results in an explicit hypothesis of relationships and a fully resolved clado gram, resolution within sect. Subacaulia is low. For analysis of the l atter, seven different outgroups were used and, in each one, the succe ssive approximations weighting procedure (available in the program Hen nig86) was followed to improve resolution. Despite this, lower nodes i n the cladogram remained unresolved, and strict consensus trees of all the analyses resulted in only a few replicated subterminal clades. Th ese results are discussed in connection with biogeographical data and with the hypothesis that representatives of sect. Subacaulia are schiz oendemics. (C) 1995 The Linnean Society of London