Author
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Dong LN, Wang H, Wortley, AH, Lu L, Li DZ.
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Abstract
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The Pterygiella Complex,
i.e. Pterygiella,Phtheirospermum, Pseudobartsia and Xizangia, is controversial in terms of both its
relationships and taxonomic status. The genera of the complex are all
species-poor and endemic to eastern Asia. In this study, we sampled all taxa
within the complex for seven genic regions (atpB-rbcL, atpH-I, psbA-trnH, rpl16 intron, trnL-F, trnS-G and ITS), which were analysed separately
and in combination. We examined capsule and seed morphology of these genera
by scanning electron microscopy (SEM). Our results indicate that the complex
is a polyphyletic group comprising two distinct clades. The first clade,
designated “Pterygiella Complex
I”, includes only Phtheirospermum
japonicum. This clade is
uniquely diagnosed by its papery yellow capsule and reticulate secondary
thickening on the seed coat. The second clade, “Pterygiella Complex II”, includes Phtheirospermum tenuisectum, Phtheirospermum parishii, Phtheirospermum
muliense,Psuedobartsia, Xizangia and Pterygiella. These taxa share a coriaceous capsule. Pterygiella itself is a monophyletic group characterized by
eglandular, unicellular, pilose hairs on the capsule and hook-like
protuberances on the horizontal ridges of the striate or reticulate seed
coat. ExcludingPhtheirospermum japonicum, the remaining taxa in Phtheirospermum cluster together and are sister to Pterygiella. Xizangia
bartschioides and Pseudobartsia yunnanensis are separated from Pterygiella and Phtheirospermum respectively, and are supported as genera
by both molecular and morphological evidence.
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