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This paper gives the descriptions, habitats and distributions of 16 species of Euphrasia found in North America. The introduction contains a historical account of the discovery and treatment of these species and an account of their morphology, breeding biology, parasitism and species concept. A conspectus of the classification and an artificial key to the species is included.

The present paper deals with the anatomical description of five taxa belonging to the genus Fuirena. These can be divided into two groups: (i) F.wallichiana and F.umbellata; with short, cubical silica-cells each containing one or two cone-shaped silica-bodies, and (ii) F.uncinata, F.ciliaris and F.pubescens var.pergamentacea, with long silica-cells each containing two to six silica-bodieS. Further distinction at the specific level is possible on the basis of the presence or absence of wedge-shaped silica deposits, the nature of the anticlinal walls, the outline of the inner stomatal pore and the size of the inter-stomatal cellS. A characteristic type of stoma revealing an inner astroporous condition is also reported. A key based on the characters visible in the surface views of leaf is presented.