Abstract
The cliff fern family Woodsiaceae has experienced frequent taxonomic changes at the familial and generic ranks since its establishment. The bulk of its species were placed in Woodsia, while Cheilanthopsis, Hymenocystis, Physematium, and Protowoodsia are segregates recognized by some authors. Phylogenetic relationships among the genera of Woodsiaceae remain unclear because of the extreme morphological diversity and inadequate taxon sampling in phylogenetic studies to date. In this study, we carry out comprehensive phylogenetic analyses of Woodsiaceae using molecular evidence from four chloroplast DNA markers (atpA, matK, rbcL and trnL–F) and covering over half the currently recognized species. Our results show three main clades in Woodsiaceae corresponding to Physematium (clade I), Cheilanthopsis–Protowoodsia (clade II) and Woodsia s.s. (clade III). In the interest of preserving monophyly and taxonomic stability, a broadly defined Woodsia including the other segregates is proposed, which is characterized by the distinctive indument and inferior indusia. Therefore, we present a new subgeneric classification of the redefined Woodsia based on phylogenetic and ancestral state reconstructions to better reflect the morphological variation, geographic distribution pattern, and evolutionary history of the genus. Our analyses of the cytological character evolution support multiple aneuploidy events that have resulted in the reduction of chromosome base number from 41 to 33, 37, 38, 39 and 40 during the evolutionary history of the cliff ferns.
Highlights
The cliff fern family Woodsiaceae, as recently circumscribed [1,2], comprises about 35–36 species with its diversity in boreal or temperate zones of the Northern Hemisphere, and extending to Central and South America, and southern Africa [3,4,5,6,7]
Our phylogenetic results show that Woodsia including Cheilanthopsis, Protowoodsia and Physematium (BSMP = 74; BSML = 96; posterior probabilities (PPBI) = 1.00) is a distinct lineage from the athyrioid ferns (Anisocampium, Athyrium, Cornopteris, Deparia, and Diplazium), in accordance with previous studies of the phylogeny of eupolypod II ferns [2,23,27,28]
We confirm the recognition of Woodsiaceae as circumscribed by Christenhusz et al [1] and Rothfels et al [2] as separate from Athyriaceae
Summary
The cliff fern family Woodsiaceae, as recently circumscribed [1,2], comprises about 35–36 species with its diversity in boreal or temperate zones of the Northern Hemisphere, and extending to Central and South America, and southern Africa [3,4,5,6,7]. The cliff ferns are morphologically variable in their leaf shape, indument, and indusia (Fig 1A–1F), and mainly occur on exposed or shaded banks, rock outcrops, or talus slopes.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
