Premise of research. One of the most conspicuous aspects of island floras is the relatively high proportion of woody species. Often, but not always, these woody species have developed wood on the islands and have evolved from herbaceous continental ancestors, a phenomenon known as insular woodiness. Shifts from herbaceousness toward increased woodiness also occur on continents (the broader term "secondary woodiness" is more appropriate here and includes insular woodiness), but comprehensive worldwide knowledge about secondary woodiness within angiosperms remains lacking. We update hypotheses regarding the herbaceous ancestry of woody Canarian lineages in a molecular phylogenetic context and investigate the possible link of secondary woodiness and paedomorphic wood features in the Carlquistian sense.Methodology. We have assembled available literature data from molecular phylogenetic studies, wood anatomical descriptions, floras, and taxonomic revisions to identify the native secondarily woody taxa.Pivotal results. In total, at least 220 native Canary Island species of flowering plants, from 34 genera representing 15 families, are truly insular woody. This represents a significant portion of the native nonmonocot angiosperm species on the Canaries, and all of the insular woody species have paedomorphic wood features in the Carlquistian sense, although this wood anatomical syndrome might be more related to particular life forms. The majority of these insular woody groups typically grow in the markedly dry lowland regions, suggesting a possible link between secondary woodiness and increased drought resistance.Conclusions. The Canary Island flora is characterized by at least 38 independent shifts toward insular woodiness, representing an important portion of the endemic angiosperms on the archipelago. These convergent evolutionary events emphasize the remarkable lability in growth forms between herbaceous and woody lineages, but it remains puzzling which environmental variables trigger these shifts and how these independent shifts are regulated genetically.

SUMMARYMany plant genes are known to be involved in the development of cambium and wood, but how the expression and functional interaction of these genes determine the unique biology of wood remains largely unknown. We used the soc1ful loss of function mutant -the woodiest genotype known in the otherwise herbaceous model plant Arabidopsis -to investigate the expression and interactions of genes involved in secondary growth (wood formation). Detailed anatomical observations of the stem in combination with mRNA sequencing were used to assess transcriptome remodeling during xylogenesis in wild-type and woody soc1ful plants. To interpret the transcriptome changes, we constructed functional gene association networks of differentially expressed genes using the STRING database. This analysis revealed functionally enriched gene association hubs that are differentially expressed in herbaceous and woody tissues. In particular, we observed the differential expression of genes related to mechanical stress and jasmonate biosynthesis/signaling during wood formation in soc1ful plants that may be an effect of greater tension within woody tissues. Our results suggest that habit shifts from herbaceous to woody life forms observed in many angiosperm lineages could have evolved convergently by genetic changes that modulate the gene expression and interaction network, and thereby redeploy the conserved wood developmental program.

AbstrAct. The era or Carlyle Luer, which currently comprehends the forty-two years since the publication of the first Icones Pleurothallidinarum in 1975, has witnessed a true revolution in the knowledge and understanding of the species belonging to the subtribe. When Luer came into the scene, after more than two hundred years of Pleurothallidinae history, there were just about 4,000 published taxon names in the subtribe, including 52 generic names and barely 1,650 accepted species. Today there are 12,133 published taxon names, including 164 generic names, and 5,114 currently accepted species belonging to the subtribe. This means that during the Luerian era published taxa, accepted or otherwise, were tripled. During this period the rate of species description has been about 85-90 species per year, and there is nothing suggesting this rate will slow down anytime soon. If this trend is maintained, as we believe it will, by the year 2026, the subtribe will include close to six thousand accepted species.