
%0 Journal Article
%A Williams, EG 
%A Rouse, JL 
%T Disparate Style Lengths Contribute to Isolation of Species in <I>Rhododendron</I>
%J Australian Journal of Botany
%D 1988/04/01
%V 36
%N 2
%P 183-191
%K 
%R https://doi.org/10.1071/BT9880183
%U https://www.publish.csiro.au/paper/BT9880183 
%X For a group of closely related Rhododendron species in section Vireya, it is shown that success of interspecific pollinations is significantly dependent on male/female style length ratio (SLR), and apparently independent of whether both species belong to the same taxonomic subsection. Crosses with SLR < 0.2 or SLR > 6 were unsuccessful, with the probability of success increasing as SLR approached 1.0. When SLR was < 0.2 pollen tubes of the shorter-styled species were unable to reach the ovary. When SLR was > 5-6, pollen tubes of the longer-styled species penetrated deeply into the ovary but were rarely observed to enter ovules. Disparate style lengths are therefore a major incongruity factor among Vireya rhododendrons, and may contribute to species isolation. 
