(American Journal of Botany. ;90:0.)
© Botanical Society of America, Inc.
Tracking invasive fern in Florida
Lott et al. examine the reproductive biology of two invasive species of the fern Lygodium, responsible for disrupting native communities in Florida and throughout the Gulf Coast (see cover). The authors hypothesize that these species are among the few ferns that can produce sporophytes from a single isolated gametophyte, perhaps the result of long-distance dispersal, and that this ability is, at least in part, responsible for their success as invaders. The application of breeding method experiments to provide compensation trends for an explanation of the tempo of their spread is quite instructive, and the results suggest future problems for research by molecular-genetical specialists.
(see p. 1144)
A paper by Liu and Koptur compares the success of fruit and seed set in two populations of a rare endemic herb in the Lower Florida Keys, the big pine partridge pea (Chamaecrista keyensis). The populations studied were located in a natural habitat and at an urban-wildland interface. Pollinator pool composition was compared as well as factors that may have contributed to pollinator abundance. The topic is one in need of empirical studies, for although it seems obvious that development and urbanization are detrimental to natural populations of plants and animals, this is not necessarily easy to demonstrate. The authors contribute to our understanding of the types of changes that can be expected at the urban-wildland interface, hopefully motivating others to examine similar issues.
(see p. 1180)
Taylor et al. present data on phylogenetic relationships among mycorrhizal fungi that are associated with a nonphotosynthetic desert orchid Hexalectris spicata and two close relatives. Their paper highlights how little we know about the ecology of mycorrhizal fungi and orchids-for example, basic knowledge such as how many fungal taxa are associated with orchids and the degree of dependence between mycorrhizal fungi and their hosts. The results of this paper are exciting in that by using multiple molecular-systematic tools and morphological analysis the authors have made progress in identifying the fungal taxa and possible evolutionary relationships.
(see p. 1168)
Gravuer, von Wettberg, and Schmitt studied seed morphology and spatiotemporal dispersal characteristics in a rare New England grassland perennial, Liatris scariosa var. novae-angliae or Northern blazing star (Asteraceae). The three central questions addressed-which propagule traits influence dispersal, are there differences among populations in these traits that also differ among regions, and is there a trade-off between dispersal and germination in these species-set the stage for an interesting study. The results of their work should stimulate further questions regarding the genetic basis of the observed differences in morphology.
(see p. 1159)
