268 SEMI-CENTENNIAL OF TORREY BOTANICAL CLUB 
Мате вир а, Ph UV TTL SUN 58.7 3.69 
Тае ee Nue d TE 67.8 3.02 
Дао А Ж M oS UE m UL ci ds 53.3 4.04 
НЕПЕР de IE LS o ear о 21] 4.14 
и а (Cocos VO 41 T edu 65.5 3-47 
CODD CU атын in Ss ok ааа 54.8 3-84 
ЧОМЕ ЕНН eta аш Noi ga ha 44.1 3.85 
December. УЛ E Е ee RA 34-5 3.83 
PRU coro coa es lets wy Sep 51.3 45.28 
The average growing season, or period free from killing frost, 
is from April то to November 7, 211 days. In this respect our 
area compares favorably with some places five hundred miles 
farther south, say in Georgia and Alabama. June is the driest 
month by a small margin, but it would be hard to find a place 
with a more evenly distributed precipitation. There are no accu- 
rate data on wind, sunshine, evaporation, humidity, or snowfall; 
but the average annual amount of the last is probably something 
like two or three feet. 
VEGETATION 
Habitats. The natural vegetation may be divided into two 
habitat groups: that of uplands and that along watercourses. 
In a more detailed study the gravelly slopes of the valleys with 
the beds of the dry ones might make a third group, but the vegeta- 
tion of such places, though differing a little in composition, is so 
similar in aspect to that of the level uplands that it is hardly 
worth while to separate it. 'There is also a characteristic weed 
vegetation along roads and in abandoned fields, which will be 
discussed briefly farther on. The upland vegetation is by far 
the most extensive, but that of the valleys is (or was) a little 
richer in species. The next few pages will deal with the natural 
upland vegetation exclusively, unless otherwise indicated. 
spects. The prevailing aspect of the vegetation is a moder- 
ately dense growth of coarse grasses and other herbs, averaging 
about two feet tall, with a sprinkling of shrubs of about the same 
height, and a few trees, either solitary or in small open groves. 
All the woody plants are most abundant eastward, except the 
commonest shrub, which is pretty uniformly distributed. "There 
are no stout broad-leaved herbs like the Silphiums of the Middle 
Western prairies, but on the other hand there are few evergreens 
