180 BOTANICAL GAZETTE [SEPTEMBER 
ence in cover causes great difference in physical factors. Simulta- 
neous physical factor readings show very clearly these differences. 
The following is a typical set: 
Aug. 3, 1904, 10:45 a. m. 
TEMPERATURE REL. HUMIDITY : 
Biss ie ____| WATER 
Licut poarch 
~ Soil Plant a m cm rr TEN 
S. - od cm ™ oy = I 
oil surface | surface gs 
Ope ki 6s 24° Bote| aa? 29°6 | 2874 | 40% 32°70 | 3 ¥ 
Thicket (Quercus)| 180s 18° 30° | 28°2 | 27°2 | 26°8 | 42% | 39% | 9-3A 
: ee 
So es ; A . -hya and 
Fic. 8.—Zonation at Palmer Park; frontal zone of Bouteloua oligostachya 0” 
ee : - hase: OF 
Artemisia frigida; zone near base of the bluff Andropogon furcatus; he base 
the bluff the foothill thicket (Quercus); the bluff showing pine formation (P. s¢ 
lorum). 
rope 
apart. 
These conditions existed on the same exposures and 6™ 
Arle- 
The open quadrat was dominated by Bouteloua oli gostachya an 
mista frigida; while the shaded quadrat contained Quercus utahe? 
Sande 
1515, 
