Phylogenetic Position of Anegelica apaensis/Heracleum apaense Based on Evidence from ITS Sequences of Nuclear Ribosomal DNA

The phylogenetic position of Angelica apaensis Heracleum apaense(A.apaensis was used in the following),which belongs to Angelicinae in Umberlliferae,is controversial.To clear its phylogenetic position,ITS(internal transcribed spacer)sequences from A.apaensis and 16 other species in these two genera(4 of them were from GenBank)were used to compute their genetic distances and to construct phylogenetic trees,Notopterygium incisum was used as the outgroup.Analysis on different ITS regions resulted in contradictory conclusions:analysis on ITS1 sequences indicated that A.apaensis should belong to Ange-lica,while analysis on ITS2 sequence suggested that it belongs to Heracleum.Further studies demonstrated that A.apaensis possessed base sequence characters similar to plants in Angelica in ITS1 region,but had base sequence characters similar to plants in Heracleum in ITS2 region.Therefore,results of this study support the view that A.apaensis is a transitional taxon between Angelica and Heracleum.