Xiaodan Xu

Home at Last II: Gerbera hieracioides (Kunth) Zardini (Mutisieae, Asteraceae) is really a Chaptalia

Abstract Gerbera hieracioides (Kunth) Zardini of the Gerbera-complex (Mutisieae, Asteraceae/Compositae) is distributed in Ecuador and Peru. This perennial herb was first named as Onoseris hieracioides Kunth and was later recognised as Trichocline hieracioides (Kunth) Ferreyra. Now it is generally treated as Gerbera hieracioides (Kunth) Zardini but it has never been included in any section of Gerbera. In this study, the position of Gerbera hieracioides is assessed based on morphology and a molecular phylogeny that includes G. hieracioides and 28 other species from the Gerbera-complex. Morphologically, G. hieracioides bears leaves with the adaxial epidermal surface without stomates but with soft thin trichomes, bracteate scapes, trimorphic capitula and inner ray florets with the corolla shorter than the style. These characters suggest that the species is most closely related to Chaptalia rather than to Gerbera or Trichocline. Furthermore, the phylogenetic results based on two nuclear (ITS and ETS) and two chloroplast (trnL–trnF and trnL–rpl32) sequences strongly support the placement of G. hieracioides nested within Chaptalia. As both morphological characters and the molecular phylogenetic results support the transfer of G. hieracioides to Chaptalia, this enigmatic taxon is recognised as Chaptalia hieracioides (Kunth) X.-D. Xu & W. Zheng.

The Ethnic Textile Use of Natural Fibers from Fireweed (Gerbera delavayi) in Southwest China

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Home at last III: Transferring Uechtritzia and Asian Gerbera species into Oreoseris (Compositae, Mutisieae)

Abstract Recently the Asian Gerbera species were shown to form a clade that was not the sister group of the African Gerbera. In this study, the position of the Asian Gerbera species was further assessed based on morphology and molecular phylogenetic analyses that included six Asian Gerbera and 26 other species from the Gerbera-complex. Morphological results showed that the six Asian Gerbera species, which were sampled, bear leaves with the adaxial epidermal surface lacking stomates, possess bracteate scapes and lack inner ray florets. These characters suggest that the Asian Gerbera species are most closely related to the species of Uechtritzia, which also share similar pollen grain size and shape with the Asian Gerbera, rather than to the African Gerbera. Furthermore, the phylogenetic results based on two nuclear (ITS and ETS) and three chloroplast (trnL–trnF, trnL–rpl32 and trnC–petN) sequences strongly support the Asian Gerbera and Uechtritzia forming a clade, with the latter nested within the Asian Gerbera species. Both morphological and molecular phylogenetic data thus confirmed the taxonomic identity of the Asian Gerbera and Uechtritzia. The authors herein formally treat the nine species of the Asian Gerbera and the three species of Uechtritzia as members of the genus Oreoseris, which is the earliest generic name of this lineage and has the nomenclatural priority.

Assessing the maternal origin in the polyploid complex of Camellia reticulata based on the chloroplast rpl16 intron sequences: implications for camellia cross breeding

Camellia reticulata is a well-known woody ornamental species endemic to Southwest China. It represents a polyploid complex with diploids, allotetraploids, and allohexaploids. The parentage of the allotetraploids and allohexaploids has been reported by genomic in situ hybridization, but the maternal parents still remain unknown. In this study, sequences of the chloroplast rpl16 intron of 105 cultivars of C. reticulata and 7 congeneric species were used to infer the maternal origin of the allopolyploids. The results showed that (1) the allotetraploids were derived from C. pitardii as the maternal parental species and the diploid C. reticulata as the paternal parental species; (2) the allohexaploid C. reticulata was derived from the allotetraploid C. reticulata as the maternal parent and C. saluenensis as the paternal parent; and (3) the C. reticulata cultivars were derived from hexaploid C. reticulata as the maternal parents. These results indicated that C. pitardii, the allotetraploid and allohexaploid C. reticulata may serve as good potential maternal parents for the cross breeding of Camellia.