Taxonomic status and distributional range of Aconitum angustius (Ranunculaceae) based on cytological evidence

Aconitum sinomontanum Nakai var. angustius W. T. Wang (Ranunculaceae) has been recorded to occur only in the Anhui, Jiangxi and Hunan provinces, China. However, it is here revealed to be a much more widespread tetraploid (2n = 32) entity almost allopatric with the diploid (2n = 16) A. sinomontanum s.s. The former entity has a southern distribution in China, occurring in Anhui, Chongqing, northern Guangxi, Guizhou, southern Henan, northwestern Hubei, Hunan, and Jiangxi, while the latter has a relatively northern distribution, occurring in northeastern Chongqing, southern Gansu, Hebei, western Henan, western Hubei, eastern Qinghai, Shaanxi, Shanxi, and Sichuan. There is only minor overlap of the geographical distributions of the diploid and tetraploid populations, with both entities documented as co‐occurring in northeastern Chongqing and northwestern Hubei. The two entities also are very different from each other in karyotypic constitution. As A. sinomontanum var. angustius is fairly well differentiated from A. sinomontanun in external morphology, ploidy level, karyotypic constitution and geographical distribution, it seems justified to recognize A. sinomontanum var. angustius , an entity possibly of allopolyploid origin, as the independent species A. angustius (W. T. Wang) W. T. Wang.