茎高约1米，锐四稜形，具槽，近于无毛，仅节上及槽内有时被倒伏小绒毛
Engler, Bot. Jahrb. 29: 556. 1900; Dunn in Notes Bot. Gard. Edinburgh 6: 188. 1915; Kudo in Mem. Fac. Sci. Agr. Taihoku Univ. 2: 185-1929; C. Y. Wu in Act. Phytotax. Sin. 8 (1) : 46. 1959; Hsuan in ibid. 10 (1) : 54. 1965
淡黄色
7-8月