* 





1917] CURRENT LITERATURE 243 



varied types, presenting ecological problems of peculiar interest. The more 

 xerophytic type of such grassland has been studied in South Boulder Park by 

 Ramaley 5 and by him designated "dry grasslands' ' in contrast to the more 

 mesophytic "meadow." One of the most interesting problems of the park is 

 the relationship of these two phases of grassland, and one must regret that it 

 has been so slightly touched upon in the present paper. Another deficiency 

 is the limited number of data regarding the environmental factors. Some soil 

 moisture studies seem to show that the growth water is not abundant in any 

 association, although unfortunately the relationship of the soils of which wilting 

 coefficient determinations were made and those whose water content were 

 studied is not clearly apparent. Wilting coefficients ranging from 3.5 to 7.6 

 indicate to some extent the coarse texture and low water-retaining power of the 

 soil which, combined w r ith such climatic factors as short summers, high winds, 

 and an annual rainfall of 28 inches, tend to retard the development of meso- 

 phytic vegetation. 



A most interesting seasonal succession is described, ranging from a pre- 

 vernal period extending from May 1 to June 15 and characterized by the bloom- 

 ing of Mertensia Bakeri and Thlaspi purpurascens, through well marked vernal, 

 early and late aestival, to an autumnal in which the bloom is almost entirely 

 limited to late grasses and blue gentian. 



The series of associations involved in the xerarch succession here in progress 

 proceeds from one characterized by Erigeron multifidus and Selaginella densa 

 on recently exposed soil, through others in which Carex stenophylla associated 

 with certain Leguminosae and Compositae such as Aragallus Lambertii and 

 Chrysopsis villosa gradually give place to others in which grasses become 

 increasingly abundant and important. The author regards the ultimate 

 grassland vegetation as an association in which the grasses represented by 



Muhlenh 



Whether 



this will pass eventually to the more mesophytic meadow, and it in turn be 

 replaced by forest, seems at present to be a probability not demonstrated. In 

 spite of this and other unsolved problems, the present discussion, together with 

 the careful analyses of the same author 6 previously published, very greatly 

 advances our knowledge of these interesting grasslands.— Geo. D. Fuller. 



Taxonomic notes. — Berry 7 has described a new species of Zamia (Z. 

 mississippiensis) from the Lower Eocene of Missisippi. It has "slender, 

 graceful leaves and much reduced oinnules suggestive of Z. floridana" 



« Ramaley, F., Dry grasslands of high mountain park in northern Colorado. 

 Plant World 19:249-270. figs. 6. 1916. 



, The relative importance of different species in a mountain grass-land. 



# - — 



Bot. Gaz. 60:154-157. 1915. 



grassland. Bot. Gaz. 62:70-74. 1916. 

 ^ Berry, E. W., A Zamia from the Lower Eocene. Torreya 16:177-179- 



mountain 



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