New Zealand Journal of Botany abstract
Gender dimorphism in indigenous New Zealand seed plants
C. J. WEBB
Foundation for Research, Science and Technology
P.O. Box 12-240
Wellington, New Zealand
DAVID G. LLOYD
Department of Plant and Microbial Sciences
University of Canterbury
Private Bag 4800
Christchurch, New Zealand
LYNDA F. DELPH
Department of Biology
Indiana University
Bloomington
Indiana 47405, USA
Abstract The frequent occurrence of gender dimorphism has
long been recognised as one of the distinctive features of the New Zealand
flora. We list 83 seed plant genera in which gender dimorphism occurs, and
document habit, pollination, and dispersal characters for each genus. This
means that gender dimorphism is represented in 23% of the genera in the flora;
however, not all of these genera are uniformly dimorphic in gender--40% of them
include some species or populations that lack gender dimorphism. We estimate
that gender dimorphism has arisen autochthonously in 17 of the 83
genera--therefore, gender dimorphism evolved elsewhere in most cases (80%), and
was established in New Zealand by subsequent migration. A comparison of the
genera in which gender dimorphism occurs with the remainder of the flora shows
that gender dimorphism is strongly correlated with fleshy fruits, and with
woody habits. No correlation was found between gender dimorphism and
pollination mode, perhaps because relatively unspecialised pollination systems
are another characteristic feature of the New Zealand flora. Among genera for
which gender dimorphism appears to have arisen autochthonously, a liane habit
seems to have been a contributing factor, whereas fleshy fruit and pollination
mode were not.
Keywords gender dimorphism; sex; dioecism; gynodioecism;
reproductive biology; breeding systems; pollination; fleshy fruit; habit; seed
plants; islands; New Zealand
B98004
Received 14 January 1998; accepted 3 June 1998
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