扁枝石松属

Holub in Preslia 47: 104. 1975; Ching in Acta Phytotax. Sinica 16(3): 7. 1978, et in Acta Bot. Yunnan. 3(1): 4. 1981 et 4(2): 127. 1982 (#$#Diaphastrum#$#, #$#Diaphasiastrum#$#) ; Fl. Xizang. 1: 14. 1983; Dixit, Census Ind. Pterid. 10. 1984, et Lycop. Ind. 83. 1988: Fl. Intramong. 1: 51. 1985; H. S. Kung, Fl. Sichuan. 6: 50. 1988; J. Z. Wang in Journ. Hebei Forest. coil. 5(2): 116. 1990; B. Ollg. Index Lycop. 6. 1989: Bir et al. in Ind. Fern J. 6: 33. 1989; S. H. Wu et Ching, Fam. Gen. Pterid. Sin. 107. 1991: S. H. Wu, J. N. Zhu et C. Y. Yang, Dict. Extant & Fossil Fam. Gen. Chin. Ferns 37. 1992; Fl. Xinjiang 1: 5. 1992; Fl. Jiangxi 1: 21. 1993; Fl. Zhejiang 1: 5. 1993; L. B. Zhang et H. S. Kung inActa Phytotax. Sin. 38(3): 272. 2000. —— Lycopodium Subgen. Complanatostachys Herter in Bot. Engl. Jahrb. 43: Beibl. 98: 29. 1909. P. P. —— Lycopodium Subgen. Thujophyllium Boerner, Fl. Deut. Volk. 110. 1012. —— Lycopodium Subgen. Lycopodium Sect. Complanata Victorin in Contr. Lab. Bot. Univ. Montreal 3: 34, 89. 1925; Wilce in Beih. Nova Hedwigia 19: 1-233. 1965: De Vol in H. L. Li, Fl. Taiwan 1: 38. 1975. —— Diphasium Presl ex Rothm. Ser.Complanata Rothm. in Fedde, Repert. Sp. Nov. 54: 64. 1944; U. Sen et T. Sen in Fern Gaz. 11(6): 423. 1978. —— Lycopodium sensu J. C. Tsai et W. C. Shieh in T. C. Huang, Fl. Taiwan ed. 2, 1: 29. 1994. p. p.

小型至中型土生蕨类，主茎伸长呈匍匐状。侧枝近直立，多回不等位二叉分枝，小枝扁平或为扁压状。叶螺旋状排列或4行排列，密集，三角形或钻形，基部贴生在枝上，下延，无柄，先端尖锐，略内弯，边缘全缘，中脉不明显，厚草质或革质。孢子囊穗生于孢子枝顶端，圆柱形，淡黄色；孢子叶宽卵形，覆瓦状排列，先端急尖，尾状，边缘膜质，具不规则锯齿；孢子囊生于孢子叶腋，内藏，圆肾形，黄色。孢子四面球形，极面观近圆形，赤道面观扇形。染色体基数 x＝23。

全属约23种，主要分布于北半球温带和热带。我国有3种1变种。