The herbarium was founded in 1882 and contains ~588,000 specimens of north temperate vascular plants, especialy from Canada. Important collectors and collections include T.M.C. Taylor; G. Lawson; R. Bell; N.V. Polunin; R.C. Hosie; A.E. Porsild; J.H. Soper; G.M. Dawson; J. Macoun; W.K.W. Baldwin; H.J. Scoggan; J.M. Gillett; J. Bell; J.M. Macoun; W. Spreadborough; G.W. Argus; M.L. Fernald; A.P. Low; and M.O. Malte.

This herbarium incorporated specimens from part of the LCU (about 10,000 Canadian and arctic specimens), the Geological Survey of Canada, PFES in 2994, and OTF in 1994.