Weston L. Testo

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Ferns are the second-most diverse lineage of vascular plants on Earth, yet the best-sampled time-calibrated phylogeny of the group to date includes fewer than 5% of global diversity and was published seven years ago. We present a time-calibrated phylogeny that includes nearly half of extant fern diversity. Our results are evaluated in the context of(More)
The emergence of angiosperm-dominated tropical forests in the Cretaceous led to major shifts in the composition of biodiversity on Earth. Among these was the rise to prominence of epiphytic plant lineages, which today comprise an estimated one-quarter of tropical vascular plant diversity. Among the most successful epiphytic groups is the Polypodiaceae,(More)
Homosporous vascular plants utilize three different mating systems, one of which, gametophytic selfing, is an extreme form of inbreeding only possible in homosporous groups. This mating system results in complete homozygosity in all progeny and has important evolutionary and ecological implications. Ferns are the largest group of homosporous land plants,(More)
The generic classification of huperzioid Lycopodiaceae was tested using Bayesian inference and Maximum likelihood phylogenetic analyses of DNA sequences from four chloroplast loci for 119 taxa and optimisation of 29 morphological characteristics onto the phylogeny. Consistent with previous studies, the subfamilies Lycopodioideae and Huperzioideae are(More)
PREMISE OF THE STUDY Understanding the ecology of rare species can inform aspects of conservation strategies; however, the mechanisms of rarity remain elusive for most pteridophytes, which possess independent and ecologically distinct gametophyte and sporophyte generations. To elucidate factors contributing to recent declines of the rare fern Asplenium(More)
PREMISE OF THE STUDY A central goal of plant ecophysiological studies is to generate patterns of physiological behavior that are applicable to a species, which can be complicated when plant size is considered. Studies indicate that plant size can influence numerous ecophysiological parameters, especially in vascular epiphytes. The few studies that have(More)
Hybridization is an important evolutionary force in plants, but the mechanisms underlying it have not been well studied for many groups. In particular, the drivers of non-random patterns of interspecific gene flow (asymmetrical hybridization) remain poorly understood, especially in the seed-free vascular plants. Here, we examine patterns of asymmetrical(More)
PREMISE OF THE STUDY This paper investigates the occurrence and evolution of aluminum (Al) accumulation within ferns and lycophytes, which is characterized by Al concentrations above 1000 mg·kg-1 in aboveground plant tissues. We hypothesize that this feature is more common in ferns than in angiosperms, and potentially correlated with growth form and other(More)
Here we evaluate the origins and relationships of Mexican and Central American Diplazium hybrids derived from crosses involving either D. plantaginifolium or D. ternatum. Based on study of live plants and herbarium specimens, we distinguish D. ×verapax from the similar D. riedelianum and present evidence that the former is a sterile hybrid derived from a(More)
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