Tese
The fern family Blechnaceae:old and new genera re-evaluated, using molecular data
Fecha
2016-02-25Autor
André Luís de Gasper
Institución
Resumen
Blechnaceae is a monophyletic family of worldwide distribution, having Blechnum
occidentale L. as type species. The family is characterized by petioles with two or more
vascular bundles at the base, commissural vein parallel to the costae, cenosori borne on these
commisural veins, indusia opening inwardly, and reddish young fronds. The family was
divided, traditionally, into two major groups, the monomorphic and dimorphic species,
however, this division has been questioned. The first classification proposed follow this
division and two genera was accepted: Blechnum L. and Lomaria Willd., but afterwards
others proposes was made. The proposal so far adopted was elaborated in the 90s, where
nine genera were recognized in two subfamilies, being Blechnum, Brainea J. Sm., Doodia
R. Br., Pteridoblechnum Hennipman, Sadleria Kaulf., Salpichlaena J. Sm.,
Steenisioblechnum Hennipman and Woodwardia Sm. in Blechnoideae, and, Stenochlaena
Ching in Stenochlaenoideae. The highest species richness is in the genus Blechnum that is
also sub-cosmopolitan, with two main diversity centers in Neotropics and Oceania. More
recently a new genus was recognized, Telmatoblechnum Perrie et al., with the segregation
of two species of Blechnum, and Doodia, Steenisioblechnum and Pteridoblechnum were
included in Blechnum However, even then Blechnum remained paraphyletic. In order to test
the congruence of the genera, we have assembled the broadestsequence dataset thus far (ca.
60%), including three plastid regions (rbcL, rps4-trnS, trnL-trnF intergenic spacer region)
and with taxonomic sampling focused on both major diversity centers. Our sampling
includes 160 taxa and 183 newly generated sequences. We recognize three subfamilies, all
with high support in the three analyzes performed: Maximum Parsimony, Maximum
Likelihood and Bayesian Inference. The genera Salpichlaena, Stenochlaena, and
Telmatoblechnumare monophyletic, but Blechnum, in its current (historical) circumscription
is polyphyletic, because Brainea, Doodia, and Sadleria all nest within it. Based on these
results, we propose the recognition of 24 genera, been six new and the other resurrected, and
new combinations for allspecies.In addition, descriptions an identification key for all genera
was prepared.