(American Journal of Botany. ;91:0.)
© Botanical Society of America, Inc.
Clonal architecture in coastal redwood
Douhovnikoff et al. use genetic finger-printing techniques to identify clones in coastal redwood (Sequoia sempervirens) at nine sites within the Jackson Demonstration State Forest on the northern coast of California. Their impressive data set yields information on the type of clonal architecture present, with implications for the evolution and ecology of the species. This well-designed study should prove of significant interest to the botanical and natural resource management communities.
(see p. 1140)
Graham and Barrett investigate the evolution of heterostyly in the amaryllid genus Narcissus. They reconstruct both phylogeny of the genus and evolution of floral shape in the genus, which possesses striking floral diversity with at least four stylar conditions. Using rapidly evolving regions from the plastid genome, Graham and Barrett provide the first phylogenetic evidence that distyly has evolved from stigma-height dimorphism, as predicted by theoretical models. Their novel use of the concentrated-changes test (CCT) indicates the importance of the long floral tube and deep corolla as the functional basis for the origin of heterostyly.
(see p. 1007)
Over 50 years ago Ownbey published an historical color plate in the American Journal of Botany announcing the discovery of newly formed allotetraploids of Tragopogon. In this issue there is new work on the topic and a new picture (see front cover). Pires et al. present compelling evidence for relative genomic stability following tetraploidization in Tragopogon. They employ a number of techniques to analyze the genomic structure of two recently derived Tragopogon tetraploids and their diploid progenitors.
(see p. 1022)
Steets and Ashman present an interesting and thorough study that examines the effect of herbivory, natural and simulated, on pollinator visitation and the production of cleistogamous flowers in Impatiens capensis. They also test for transgenerational effects by measuring the performance of offspring generated by cleistogamous and chasmogamous flowers. The authors point out that despite a vast literature on plant-herbivore interactions, only recently have studies begun to look at the effects of herbivory on pollinators, and very few have looked at the effects of herbivory on mating systems.
(see p. 1046)
