266 FRANCIS RAMALEY 



TABLE 4 

 Geographic and altiludinal distribution of the dry grassland species 



Number of species ranging chiefly to the north 79 



Number of species ranging chiefly to the south 7 



Number of species ranging to both north and south 46 



Number of species ranging chiefly to higher altitudes 10 



Number of species ranging chiefly to lower altitudes 43 



Number of species ranging about equally up and down 79 



FREQUENCY OF OCCURRENCE OF DIFFERENT SPECIES 



The plants already mentioned as prominent at the different 

 seasons and those designated as important in the various socie- 

 ties are the ones most noticed in any examination of the dry 

 grassland here considered. Quadrat studies,^^ to determine the 

 relative frequency of different species show that Muhlenber- 

 gia is the grass which occupies the greatest amount of ground, 

 while Carex stenophylla is of most importance among the sedges. 

 Koeleria and the species of Danthonia, Festuca, and Poa, are 

 prominent. Dicotyledonous plants may be mentioned in about 

 the following order: Artemisia frigida, Aragallus spp., Anten- 

 naria spp., Cerastium occidentale, Mertensia hakeri, Chrysopsis 

 foliosa, Sedum stenopetalum. The relative standing of less im- 

 portant members of the vegetation is difficult to determine 

 and varies much in the different societies or aspects. The only 

 pteridophyte, Selaginella densa, is found in nearly every quadrat 

 except such as are in the Vaccinium society. 



DURATION OF INDIVIDUAL PLANTS 



Nearly all the dry grassland plants are perennials; most of 

 them live for many years. Only 12 species, aggregating about 

 9% of the flora, are annuals or biennials, and even some of these 

 may endure more than two years. They are the following: 

 Festuca octoflora, Hordeum juhatum, Polygonum engelmannii, 

 Capnoides aurea, Arabis connexa, Arahis divaricarpa, Thlaspi 

 purpurascens, Micranthes rhomhoidea, Gayophytum ramosissimum, 



^^ Ramaley, Francis, The relative importance of different species in a moun- 

 tain grassland. Bot. Gaz., 60: 154-57, 1915. 



Ramaley, Francis, Quadrat studies in mountain grassland. Bot. Gaz., 62: 

 70-74, 1916. 



