92 BOTANICAL GAZETTE [august 



pubescent with stellate hairs. It is scarce and its small white flower 

 inconspicuous, so in no respect does it influence the floral tone. 

 Ranunculus is even more restricted, occurring sparsely on lowest 

 slopes and in depressions on the higher slopes, and is apparently 

 related to a high water content of the soil. Its yellow petals soon 

 fall, and its presence might easily be overlooked in a casual survey 

 of the formation. It is a perennial and is an index of mesophytic 

 conditions. Astragalus, with its racemes of violet-purple flowers, 

 is easily marked in the formation. While generally distributed, its 

 abundance is sparse to subcopious, yet frequently it assumes a gre- 

 garious habit. It is a perennial of thickened tap roots which branch 

 above and eventually fragment behind, establishing new individuals. 

 Its migration is slow; dispersal is effected mainly by gophers, which 

 store the fruits for winter consumption. However, ecesis is very 

 certain. 



Vernal floral aspect 



Toward the last of the first or the beginning of the second week in 

 May there is a floral outburst inaugurated by the blooming of Notho- 

 calais cuspidata and Lithospermum angust [folium, closely followed 

 by Castilleja sessiliflora, Lithospermum canescens, Viola pedatifida, 

 and Oxalis violacea, which marks the inception of the vernal floral 

 aspect. Forms are now progressively added up to about the first 

 week of June, when the aspect is distinctly terminated by the general 

 blooming of certain sod-formers. Astragalus crassicarpus and Ranun- 

 culus ovalis have extended over into this aspect, the former reaching 

 its maximum flowering about the second week in May, thus entering 

 conspicuously into the vernal period. The fruiting scapes of Pcu- 

 cedanum nudicaule enter into the tone, while Antennaria campestris 

 with its white fruiting heads is now more noticeable than earher. 

 The deadened brown tone of the prevernal aspect is at last relieved 

 and replaced by the green of the grassy sod, which is rendered some- 

 what bizarre by the very general distribution of some twenty-eight 

 flowering forms, the largest number occurring in any aspect. No 

 floral facies is developed except in the case of Poa pratensis at the 

 base of slopes, and then only in the later part of the aspect. ]\Iost 

 of the prairie annuals have by the later part of the aspect appeared 



