Viburnum

I was exploring a new satoyama when I saw this empty wild plot of land which had nothing but tall grasses and this viburnum tree. Isn’t it magnificent? I found this very interesting piece on evolution of the viburnum on Richard Winkworth’s page about the viburnum:

Viburnum phylogeny, biogeography and character evolution.

“My postdoctoral research focused on Viburnum (Adoxaceae), a genus of ~160 species widely distributed in the Northern Hemisphere and into the mountains of Southeast Asia and Latin America. Analyses of both chloroplast markers, nrITS, and low copy nuclear loci suggest broadly similar pictures of Viburnum phylogeny. However, these analyses also highlight complex patterns of diversification in some lineages. For example, the nuclear GBSSI (waxy) locus occurs as two paralogues in most viburnums, but the presence of additional copies in two clades is consistent with allopolyploidy. Further, localized incongruence between nuclear and chloroplast gene trees is consistent with previous suggestions of homoploid hybrid speciation.

Taken together dispersal-vicariance analyses and divergence time estimates suggest a complex biogeographical history for Viburnum. These analyses imply an origin and initial diversification in Asia, with later movements into Europe and the New World. Viburnum appears to have entered North America on at least five separate occasions; two Old World-New World splits fall between major clades and molecular age estimates suggest these are older events, while the remaining disjunctions occur within clades and are more recent. This result suggests that the North American Viburnum community has been assembled over a relatively long time period and therefore that any interactions between lineages will have changed over time. Our analyses also suggest complex patterns of character evolution. Several characters, such as the presence of sterile flowers on the margins of inflorescences and tri-lobed leaves, can be confidently mapped onto gene trees and have clearly arisen on multiple occasions”. Source: Richard Winkworth’s website 

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