High diversity and endemism in the California Floristic Province (CFP) are an alleged response to the late Cenozoic advent of Mediterranean-type climate in this region. Ceanothus comprises two divergent subgenera with centers of diversity in the CFP. We reconstruct the evolution of Ceanothus by using DNA sequence data from the nuclear gene nitrate reductase. We find that the timing of diversification events is related to geological and climatic history. In both subgenera, diversification is characterized by recent divergence of extant taxa and geographically structured phylogenetic relationships. A strong north-south divergence of subgenus Cerastes across the Transverse Ranges indicates that phylogenetic relationships may be structured by climatically divergent regions of the CFP. Divergence-time estimation suggests that the age of extant diversification in both subgenera is ;6 Ma. This agrees with the fossil record but predates the hypothesized Quaternary (2-Ma) origin of Mediterranean-type climate in the region.
The tribe Pomaderreae (Rhamnaceae) currently consists of approximately 180 species in seven genera, endemic to Australia and New Zealand. It is the second largest tribe of Rhamnaceae. We undertook a phylogenetic analysis using internal transcribed spacer (ITS) sequence data from 69 representative species of Pomaderreae and five outgroup taxa. The monophyly of Pomaderreae was confirmed. The clades found in the strict consensus tree are mostly consistent with the currently accepted genera of the tribe. All major clades, except Stenanthemum, received moderate to strong bootstrap and jackknife support. Only the relationship between Siegfriedia and Pomaderris received strong support; relationships between other genera did not receive support above 50%. Taxonomic changes are suggested and a preliminary classification of Pomaderreae is proposed, including the monophyletic genera Cryptandra, Pomaderris, Spyridium and Trymalium. Blackallia and Siegfriedia are monotypic. Two new genera are required: one containing two atypical species of Stenanthemum and the second genus consisting of previously unrelated species from three genera that share a 2‐carpellate ovary and a characteristic indumentum. The taxonomic status of Stenanthemum requires further examination. A split of Cryptandra into smaller genera is not supported.
We introduce the AusTraits database - a compilation of values of plant traits for taxa in the Australian flora (hereafter AusTraits). AusTraits synthesises data on 448 traits across 28,640 taxa from field campaigns, published literature, taxonomic monographs, and individual taxon descriptions. Traits vary in scope from physiological measures of performance (e.g. photosynthetic gas exchange, water-use efficiency) to morphological attributes (e.g. leaf area, seed mass, plant height) which link to aspects of ecological variation. AusTraits contains curated and harmonised individual- and species-level measurements coupled to, where available, contextual information on site properties and experimental conditions. This article provides information on version 3.0.2 of AusTraits which contains data for 997,808 trait-by-taxon combinations. We envision AusTraits as an ongoing collaborative initiative for easily archiving and sharing trait data, which also provides a template for other national or regional initiatives globally to fill persistent gaps in trait knowledge.
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