Periodical Literature. 189 



bramania Tyer in a recent article, describes the ecological adap- 

 tations of numerous native sand binders. The underground 

 stems and branches of some extend to enormous lengths. For 

 example, Cyperus arenarius sends out branches to a length of 

 fifty feet with innumerable side branches and branchlets, while 

 those of Ipomea bilboa and Canavalia obtusifolia may extend 

 forty-two and thirty-five feet respectively. It seems that the 

 families represented are practically the same as those found on 

 American sand dunes. 



C. D. H. 

 Indian Forester, February, 1909, pp. 82-07. 



Reference has already been made in this 



Ecological Journal (F. Q. VII p. 74), to studies on 



Studies the vegetation of Colorado, under the title 



in of Studies in Mesa and Foothill Vegetation. 



Colorado. This is the first of a series and includes 



Geology and Physiology of the Mesas near 



Boulder by Gideon S. Dodds; Climatology of the Mesas near 



Boulder by Francis Ramaley; Distribution of Conifers on the 



Mesas by W. W. Robbins and Gideon S. Dodds ; Distribution of 



Deciduous trees and Shrubs on the Mesas by W. W. Robbins. 



The Mesas studied are Horse Mesa and Long Mesa about two 

 miles south of Boulder, Colorado. They have been carefully 

 mapped with reference to geology, topography, soils and the dis- 

 tribution of woody species. Soil moisture seems to be the most 

 important physical factor affecting plant distribution on the 

 mesas. The upper stratum of soil on the top of the mesas is 

 coarse in texture and dries rapidly after a rain. The slopes are 

 dry except in the bottoms of ravines and along seepage areas. 



Pinus scopulorum is the dominant tree of the foothill and mesa 

 region. The woody species on the slopes of the mesas, however, 

 are chiefly deciduous shrubs and small trees. The pines on the 

 mesa fall into three well-marked age-classes. The oldest (150- 

 200 years) are distributed on the higher portions of the mesa top 

 and are relatively few in number and far apart. The middle 

 class (80-100 years) is found among the oldest trees and its 

 members extend farther out toward the end of the mesa. The 

 youngest (20-30 years) are the most abundant and grow farther 

 out than the preceding groups but do not extend entirely to the 



