Geographical variation in flower colour patterns within E. acuminatum. The circles and boxes represent wild populations and herbarium specimens, respectively. The colour of the circles and boxes represent flower colour. The 19 population codes are shown in Table 1. The left area of the red dotted line is western China. The information of 23 representative herbarium specimens is as follow: 1. B. Y. Peng 47070; 2. B. L. Guo 0540; 3. B. L. Guo 0608; 4. B. L. Guo 0607; 5. Sichuan Econ. Pl. Exped. 0013; 6. F. T. Wang 23329; 7. G. H. Yang 54343; 8. K. Y. Lang 3002; 9. Sichuan Econ. Pl. Exped. 0030; 10. T. C. Pan & G. F. Wu 105; 11. Sanxia Exped. 0729; 12. Sanxia Exped. 0821; 13. K. J. Guan et al. 0273; 14. X. B. Zhang 19; 15. Jinfoshan Exped. 0202; 16. Q. H. Chen et al. 9411; 17. J. M. Yuan 003; 18. Z. S. Zhang et al. 401131; 19. Y. Tsiang 4994; 20. S. Z. He 96410; 21. P. Zhao 807; 22. S. W. Teng 0008; 23. Z. Y. Wu 60.