A Synopsis Of An Expanded Solms-laubachia (Brassicaceae), and the Description Of Four New Species From Western China1

Abstract

Sequence data from the nuclear ribosomal ITS region and the chloroplast trnL-F were used to examine the generic delimitations of Solms-laubachia Muschl., Christolea Cambess., Desideria Pamp., Leiospora (C. A. Mey.) F. Dvořák, and Phaeonychium O. E. Schulz. Solms-laubachia, Desideria, and P. jafrii Al-Shehbaz formed a well-supported monophyletic clade, with Christolea as sister group. However, both Solms-laubachia and Desideria were polyphyletic, as they appeared in more than two positions in that clade, within which P. jafrii was embedded. The results are consistent with those based on sequences of plastid maturase (matK) and the nuclear chalcone synthase (Chs). SEM survey further reveals that the seed epidermis micromorphology of D. baiogoinensis (K. C. Kuan & C. H. An) Al-Shehbaz is most similar to that of S. lanata Botsch. Based on these findings, a comprehensive synopsis of an expanded Solms-laubachia with 26 species is presented; all species of Desideria and P. jafrii are transferred to Solms-laubachia resulting in 12 new combinations: S. baiogoinensis (K. C. Kuan & C. H. An) J. P. Yue, Al-Shehbaz & H. Sun, S. flabellata (Regel) J. P. Yue, Al-Shehbaz & H. Sun, S. haranensis (Al-Shehbaz) J. P. Yue, Al-Shehbaz & H. Sun, S. himalayensis (Cambess.) J. P. Yue, Al-Shehbaz & H. Sun, S. incana (Ovcz.) J. P. Yue, Al-Shehbaz & H. Sun, S. jafrii (Al-Shehbaz) J. P. Yue, Al-Shehbaz & H. Sun, S. linearis (N. Busch) J. P. Yue, Al-Shehbaz & H. Sun, S. mieheorum (Al-Shehbaz) J. P. Yue, Al-Shehbaz & H. Sun, S. mirabilis (Pamp.) J. P. Yue, Al-Shehbaz & H. Sun, S. nepalensis (H. Hara) J. P. Yue, Al-Shehbaz & H. Sun, S. prolifera (Maxim.) J. P. Yue, Al-Shehbaz & H. Sun, and S. stewartii (T. Anderson) J. P. Yue, Al-Shehbaz & H. Sun. Furthermore, four new species of Solms-laubachia are described from western China: S. angustifolia J. P. Yue, Al-Shehbaz & H. Sun, S. grandiflora J. P. Yue, Al-Shehbaz & H. Sun, and S. sunhangiana J. P. Yue & Al-Shehbaz (all from Sichuan Province), and S. calcicola J. P. Yue, Al-Shehbaz & H. Sun (from Xizang). Both S. linearifolia (W. W. Sm.) O. E. Schulz and S. mirabilis are lectotypified.