334 BOTANICAL GAZETTE [November 



In a hawthorn society at the mouth of a small canon at an altitude 



r 



of 1710^, observations were made at three stations. One of these 

 was in the center of the thicket, close to a small stream; this I shall 

 designate as Station E. A second station, which I have called E,, 

 was chosen about midway between the center and edge of the thicket; 

 and the third, or Station E,, was taken just at the edge of the thicket. 

 The results obtained for these three stations follow: 



Temperatures 



Station E (Observations June 12,7P.M.; 13, 6 p. m,-, July i, 8: 15 A. M.', 8,10:30 A.M.; 17,9:10 A.M.; 



August 26, 9:45 A. M.) 



■ 



— 22. 5=™ — il.2sc"> o*^^ +7.5°°" ' +9''™ +1.8"* 



Minima 14^2 13° 14° 12° * 12° t ^^^ t 



Maxima 19^ 20^75 25^ 26^5=^ 26?5 f 28° f 



* Five observations, 

 t Four observations. 



Station E, (Observations June 13, 6 p. m.; July i, 8:45 A. M.; 8, ii A. M.) 



Minima i3?6 i3?4 13*^ 



Maxima. i5?2 15^5 i6?8 



Station E3 (Observations June 13, 7 p.m.; July i, 9:15 a.m.; 8, 11:15 a.m.) 



-23. 5C™ —11.25="* o*^"" 



Minima. ^4^75 ^5^ 14*^6 



Maxima. i7?6 17^ I9?5 



Water content 



F 



Observations 1 1 . 25*=™ 22 . 5 — 1 1 . 2 5*=°* 



Station E June 14 22.8 per cent. 30.8 per cent. 



July I 25.3 per cent, 33.3 per cent. 



July 8 (raining) 25 .8 per cent. 35 .6 per cent. 



July 17 II per cent, 16.7 per cent. 



August 26 6.2 per cent. 9.6 per cent. 



Station Ex July i 14.4 per cent. 15 .4 per cent. 



July 8 (raining) 18 .6 per cent. 13 .3 per cent. 



Station Ea July i 6.2 per cent. 13 .3 per cent. 



July 8 (raining) 10.2 per cent. 16.3 per cent. 



Relative humidity 



Station E (Observations, June 12, 7 p.m.-, 13, 6 p.m.; July i, 8:15 a.m.", 8, 10:30 a.m.; 17. P^io a.m.; 



August 26, 9:45 A. mO 



7,5cm j^dm i.gm 



Minima 45 per cent. 42 per cent. 21 per cent. 



Maxima 80 par cent. 77 per cent. 77 per cent. 



Light value 

 Station E August 26 9 : 45 a. M, = 5 : 300 



(2) THE POPULUS ANGUSTIPOLIA-SALIX NUTTALLII FORMATION (fig. l) 



The transition between this and the preceding formation is a wholly 

 gradual one, the narrow-leaf cottonwood occurrinsr. as already noted, 



