The phylogenetic position of the endemic flat-needle pine Pinus krempfii (Pinaceae) from Vietnam, based on PCR-RFLP analysis of chloroplast DNA

Pinus krempfii is morphologically very unique as compared to other Pinus species by having flat leaf-like needles. Its taxonomic position has been problematic ever since its discovery. In this study, an attempt was made to infer the taxonomic status of P. krempfii through restriction fragment length polymorphism analysis of 12 PCR amplified chloroplast (cp) DNA regions. Phylogenetic analysis was conducted using 10 representatives of the two Pinus subgenera: Strobus and Pinus. In addition, to infer the position of P. krempfii in Pinaceae in relation with other genera, 14 representatives of eight additional genera were included in the analysis. Our cpDNA-based results indicate that: 1) P. krempfii clearly belongs to the genus Pinus. This result does not favour the creation of a new genus Ducampopinus in Pinaceae for this taxon. 2) Within the genus Pinus, P. krempfii is more allied with species in subgenus Strobus and differs distinctly from species in subgenus Pinus. 3) Despite the similarity in certain morphological and anatomical leaf and wood characters to Keteleeria and Pseudolarix, the cpDNA data do not support the hypothesis for close relationship between P. krempfii and these two genera.