Index. 



25 



INDEX TO VOLUME TWELVE. 

 Bergen, J. Y.— The Light Requirement of Plants 201 



Blumer, J. C. — An Arizona Mesa 7 



Observations on Cacti in Cultivation 162 



Brown, H. B. — A Peculiar Specimen of Arctium 135 



Cannon, W. A. — The Parasitism of Orthocarpus Purpurascens 259 



Coker, W. C. — A Double Flowered Sarracenia 25" 



Crocker, W. M. and Knight, L. I. — Effect of Illuminating Gas and its 



Constituents upon Flowering Carnations.. 83 



Drinkard, A, W. — See Price and Drinkard. 



Duncan, L. N. — Natural Alternation of Vegetation in its Relation to 



Permanent Pasturage 181 



Ellet, W. B.— See Fred and Ellet. 



Fred, E. B. and Ellet, W. B. — The Fixation of Nitrogen by Means of 



Bacillus Radicicola Without the Presence of a Legume.... 131 



Harshberger, J. W. — Bogs, Their Nature and Origin 34, 53 



Herre, A. W. — Suggestions for Lichen Studies 255 



Humphrey, H. B. — The Plant Societies of Monterey Peninsula. .79, 152 



Kirkwood, J. E. — Some Mexican Fiber Plants 25 



Knight, L. I. — See Crocker and Knight. 



Livingston, B. E. — Present Problems of Physiological Plant Ecology.. 41 



Roles of the Soil in Limiting Plant Activities 49 



A Repeated Cycle in Assimilation 66 



An Advance in Root Physiology 127 



The Heath of Lueneburg 231 



Lloyd, F. E.— Perennial Dodder 65 



Overlapping Habitats 73 



MacDougal, D. T. — Darwinism and Experimentation in Botany.. 97, 121 

 Influence of Aridity Upon the Evolutionary Develop- 

 ment of Plants 217. 



McCallum, W. B. — The Reciprocal Influence of Scion and Stock 281 



Parish, S. B. — Parry and Southern California Botany 158 



