
Water-color sketches of American plants, especially New England, Helen Sharp (1888-1910)
|

Flowers of the field and forest, I. Sprague, A.B. Hervey,(1880)
|

A guide to wild flowers, A. Lounsberry, E. Rowan (1899)
|

Das Pflanzenreich, Alismataceae, H.G.A. Engler , deel 15 (1903)
|