[derick] two plant ASSOCIATIONS 73 



8. Artemisia fridida, Willd. 



9. Artemisia gnaphaloides, Nutt. 



10. Ratibida columniferae, (Nutt). Woot & Standi. The 

 northern golden-rod ranges from Labrador to British Columbia and 

 south to Colorado. It has spatulate, almost entire lower leaves and 

 narrow sessible upper leaves. The inflorescence in this specimen was 

 more elongated than the type form, approaching a spike in outline. 



References 



1 Britton and Brown. Illustrated Flora of the Northern States and Canada. 

 Scribners, 1913. 



- Gray's New Manual of Botany. Am. Book Co., 1908. 



^ Rydberg, R. A. Flora of the Rocky Mountains and Adjacent Plains. New 

 York, 1917. 



■* Macoun, John. Catalogue of Canadian Plants. 



^ Clements, F. E. Plant Succession. Carnegie Institution of Washington, 1916. 



^ Cooper, W. S. The Climax Forest of Isle Royale, Lake Superior, and its 

 Development. Bot. Gaz. 55:1, 1913. 



' Crocker, William and Wilmer E. Davis. Delayed Germination in Seed of 

 Alisma Plantago. Bot. Gaz., 58, 1914. 



* Cowles, H. C. The Ecological Relations of the Vegetation on the Sand Dunes 

 of Lake Michigan. Bot. Gaz. 27, 1899. 



^ Cowles, H. C. The Fundamental Causes of Succession Among Plant Associa- 

 tions. Rep. Brit. Assoc. Sci. Winnipeg, 1909. 



1° Dacknowski, A. The Successions of Vegetations in Ohio Lakes and Peat 

 Deposits. Plant World, 15:25, 1912. 



" Maze, P. Recherches sur le Rôle de l'Oxygène dans la Germination. Ann. 

 de l'Inst. Pasteur, 14, No. 5:350, 1900. 



12 Pool, R. C. A Study of the Vegetation of the Sand Hills of Nebraska. Minn. 

 Bot. Studies, 4:189, 1914. 



13 Pound, R., and F. E. Clements. The Vegetative Regions of the Prairie 

 Province. Bot. Gaz., 25:381, 1898. 



1^ Shantz, H. C. Natural Vegetation as an Indicator of the Capabilities of Land 

 for Crop Production in the Great Plain Area. U. S. Dept. Agri., Bur. PI. Ind., Bull. 

 201, 1911. 



16 Shull, G. H. The Longevity of Submerged Seeds. Plant World, 17:329, 1914. 



1^ Shull, Chas A. The Oxygen Minimum and the Germination of Xanthium 

 Seeds. Bot. Gaz., 52:433, 1911. 



Sec IV. Sig. 6 



