玉柏（学名：Lycopodium obscurum）为石松科石松属下的一个种。

• 玉柏 Lycopodium obscurum. 中国植物物种信息数据库. [2013-01-15]. 

Lycopodium obscurum, commonly called rare clubmoss, ground pine, prince's pine or princess pine, is North American a species of clubmoss in the family Lycopodiaceae. It is a close relative of other treelike Lycopodium such as L. dendroideum and L. hickeyi. It is native to the eastern United States and southeastern Canada from Georgia to Minnesota to Nova Scotia. It grows in the understory of temperate coniferous and deciduous forests, where it is involved in seral secondary succession, growing in clonal colonies some years after disturbance has occurred. It has also been found in Japan, ******, Korea, Russian Far East, and northeastern China.