笔管草

与模式亚种的主要区别：主枝较粗；幼枝的轮生分枝不明显；鞘齿黑棕或淡棕色，早落或宿存，茎部扁平，两侧有棱角；齿上气孔带明显或不明显。

分布：日本、印度、尼泊尔、缅甸、印度支那、泰国、菲律宾、马来西亚、印度尼西亚、新加坡、新几内亚、新赫布里底群岛、新卡勒多尼亚及斐济

产地：河南、山东、江苏、安徽、浙江、福建、台湾、江西、湖北、湖南、广东、香港、海南、广西、贵州、云南、西藏、四川、陕西及甘肃

海拔：0-3200米

subsp. debile (Roxb. ex Vauch.) Hauke in Amer. Fern J. 52(1): 33. 1962: De Volin H. L. Li, Fl. Taiwan 1: 55. 1975, et in T. C. Huang, Fl. Taiwan ed. 2, 1: 60. 1994; Dixit, Census Ind. Pterid. 20. 1984: Kuo in Taiwania 30: 13. 1985; L. B. Zhang et H. S. Kung in X. C. Zhang et K. H. Shing, Ching Mem. Vol. 86. 2000. ——Equisetum debile Roxb. ex Vauch. Monogr. Preles 387. 1821; C. B. Clarke in Trans. Linn. Soc. II. Bot. 1: 594. 1880; Baker, Handb. Fern Allies 5. 1887; Alderw, Malay.Fern-allies 17. 1915; Schaffner et L. C. Li in Bull. Fan Mem. tnst. Biol. Bot9: 130. 1939: Tard.-Blot et C. Chr. in FL. Indo-Chine 7(2): 546. 1951; Fl. Hainan. 1: 14, f.4. 1964; Mehra et Bir in Res. Bull. Panjab Univ. 15(1-2): 99. 1964; Tagawa in Hara, F. E. Himal. 2: 197. 1971; Ic. Corm. Sin. 1: 117, f. 233. 1972; K. Iwats. inOhashi, Fl. E. Himal. 3: 166. 1975; Y. L. Chang et al., Sporae Pterid. Sin. 51, pl. 6: 1-3. 1976: FL. Jiangsu 1: 16, f. 13. 1977; Tagawa et K. Iwats., Fl. Thailand 3(1): 34, 1979: Fl. Fuj ian 1: 18, f. 17. 1982: K. Iwats., S. K. Wu et al. in J. Fac. Sci. Uni. Tokyo III. 14: 13. 1986; H. S. Kung, FL. Sichuan. 6: 85. PL. 26: 1-2. 1988; Bir et al. in Ind. Fern J. 6: 37. 1989: Fl. Fujian rev. 1: 18, f. 17. 1991. —— Hippochaete ramosissima (Desf.) Boerner subsp. debilis (Roxb. ex Vauch.) Sen et Sen inIsrael Journ. Bot. 22: 25. 1974. —— H. debilis (Roxb. ex Vauch.) Ching in C. Y. Wu, Fl. Xizang. 1: 29, f. 8: 4-5. 1983; P. S. Wang et X. Y. Wang in Gnizhou Sci. 1983 (2): 50. 1983; P. S. Wang, Pterid. Fanjing Mt. Nat. Res. 27. 1992: Fl. Jiangxi 1: 43, f. 31. 1993: Fl. Zhejiang 1: 19, f. 1-21. 1993; Keys Vasc. Pl. Wuling Mts. 9. 1995.