Petrak, Mexik. u. zentral-amerik. Arten d. Gattung Cirsium. 255 
in 1890 and 1891, with notes upon a few other species. (Proc. Amer. Acad. 
XXVII. Boston 1893.) 
-— and Greenman, J. M., Contributions from the Gray Herbarium of 
Harvard University. New Series. No. IX. II. New and notheworthy plants 
chiefly from Oaxaca collected by Messrs. C. G. Pringle, L. C. Smith and 
E. W. Nelson. (Amer. Journ. Sei. Ser. III. Vol. I. New Haven, Connecti¬ 
cut 1895.) 
— and S e a t o n , H. E., Contributions from the Gray Herbarium of Har¬ 
vard University. III. Additions to the Phaenogamic Flora of Mexico, 
discovered by C. G. Pringle in 1891—1892. (Proc. Amer. Acad. XXVIII. 
Boston 1893.) 
Sprengel, C. (Linne, C.), Systema vegetabilium. Ed. (18.) 16. Vol. III. 
Gottingae 1826. 
Sweet, R., The British Flower Garden. Vol. III. London 1823—1838. 
T o r r e y , J. and Gray, A., A Flora of North America. Vol. II. New York 
1841—1843. 
W a t s o n , S., Contributions to American Botany. 2. Descriptions of new 
Mexican species, collected chiefly by Mr. C. G. Pringle in 1889 and 1890. 
(Proc. Amer. Acad. XXVI. Boston 1891.) 
— Contributions to American Botany. 2. Descriptions of new species of plants, 
from Northern Mexico collected chiefly by Mr. C. G. Pringle, in 1888 and 
1889. (Proc. Amer. Acad. XXV. Boston 1890.) 
