Contributions to a Knowledge of the Mor- 
phology and Ecology of the Cactaceae ; 
II 1 . The Comparative Morphology of the 
Embryos and Seedlings. 
BY 
WILLIAM F. GANONG, Ph.D., 
Professor of Botany, Smith College, Northampton, Mass., U.S.A . 
With Plate XXVI. 
T HE present paper comprises the results of an examina- 
tion into the comparative morphological development of 
representatives of the genera of Cactaceae. In this investiga- 
tion I have had four objects in view : — 
i. To discover whether the conclusions reached by a study 
of the comparative anatomy and development at the growing- 
point of the adults in this family are sustained by a study of 
their ontogeny ; and in how far the very peculiar morpho- 
logical features of the adults are present in the embryos, and 
at what stages they develop. 
2. To determine whether the form-conditions of the 
seedlings answer or not to the form-conditions of the adults ; 
1 I. Die Morphologie und Biologie der vegetativen Theile. Flora, 1894, 
Erganzungsband, pp. 49-86. 
[Annals of Botany, Vol. XII. No. XL VIII. December, 1898.] 
Gg 
