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A natural hybrid species in Petrocosmea named Longianthera in Yanshan County, Yunnan Province is confirmed for the first time based on molecular and morphological evidence. The character count procedure of the variable characters show that Longianthera populations are characteristic of the intermediate morphological traits between its putative parents Yanshan and Petrocosmea martinii. The nuclear ribosomal internal transcribed spacer region and three chloroplast regions of matK, trnL‐F, and trnT‐L are sequenced in the putative hybrid and the related species. Both alignment of DNA sequences and the phylogenetic trees could exclude all the other species in Petrocosmea as the parental species except for Yanshan and P. martinii. Eight haplotypes in the 31 internal transcribed spacer sequences and six haplotypes in 42 cpDNA sequences were found from 14 individuals of Longianthera populations. The analyses of DNA sequences, haplotypes, and phylogenetic trees indicate that Longianthera is likely a hybrid species between its putative parents Yanshan and P. martinii, in which Yanshan might be the most possible maternal parent. Several factors may contribute to the natural hybridization between these two parental species in Petrocosmea, such as the overlapped geographic distribution, habitats, flowering periods, and shared pollinators. Finally, the new species of Yanshan and the natural hybrid species of Longianthera are described.

CYC‐like genes are widely conserved in controlling floral dorsoventral asymmetry (zygomorphy) through persistent expression in corresponding domains in core eudicots. To understand how CYC‐like gene expression is maintained during flower development, we selected Chirita heterotricha as a material and isolated the promoter sequences of the ChCYC1C and ChCYC1D genes, homologs of CYC, by inverse polymerase chain reaction. Further promoter analyses led to the identification of a putative cis‐regulatory element in each promoter matching the consensus DNA binding site for Antirrhinum CYC protein: GGCCCCTC at −165 for ChCYC1C, and GGCCCCCC at −163 for ChCYC1D. This indicates that both the ChCYC1C and ChCYC1D genes have probably evolved autoregulatory loops to sustain their expression in developing flowers. We also isolated the coding and promoter sequences of the ChRAD gene, a homolog of Antirrhinum RAD. Promoter analysis showed that the ChRAD gene promoter also contained a putative CYC‐binding site (GGCCCAC at −134). Therefore, ChRAD is likely a direct target of the ChCYC1 genes, which is similar to Antirrhinum RAD. These results imply that the establishment of floral zygomorphy in Chirita may have been achieved by the evolution of an autoregulatory loop for CYC‐like genes, which was probably accompanied by simultaneous co‐option of the RAD‐like gene into their regulatory network.

The genetic relationship of 36 Dendrobium species in China was determined based on sequence analysis of the internal transcribed spacer (ITS) region of ribosomal DNA. Aligned sequences of the complete ITS region obtained from the 36 Dendrobium species and 2 outgroup species (Epigeneium amplum and Epigeneium nakaharaei) by using PCR amplification and direct DNA sequencing. The nrDNA ITS1 of Dendrobium was 225 -234 bp and ITS2 was 239 -248 bp. Phylogenetic tree was constructed, and seven main clusters were generated among the 36 Dendrobium species. From the results, D. moulmeinense was not grouped in the classification of Dendrobium and E. amplum and E. nakaharaei were shown to be divergent from Dendrobium species. The phylogenetic relationships revealed by ITS DNA analysis partially supported previously published morphological data.

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