Die Urwelt und das Alterthum. 1820.
Linné, C. v.
Flora Suecica. 1745.
Philosophia Botanica. 1751.
Lohde, G.
Ueber die Entwicklungsgeschichte und den Bau einiger Samenschalen. Just 2:441. 1874.
MacMillan, C.
Metaspermae of the Minnesota Valley. 1892.
On the Occurrence of Sphagnum Atolls in Central Minnesota. Minn. Bot. Studies, 1:1. 1894.
On the Formation of Circular Muskeag in Tamarack Swamps. Torr. Bull., 23:500. 1896.