a 
HARPER: PINE-BARREN VEGETATION OF MIssISsIPPI 557 
‘ January July Annual | = Pexceaiage = 
Stations | |, Pasnpeentste Teaching Rainfall | ee eee 
WVAVRESDOLO ... 6 sic sce cas es | 47.2 80.9 50.50 35-9 47.2 
J OTe ie dea cod. Pn kes 47-3 | S15 50.57 30.7 42.4 
Brookhaven. . oc .c6s- 500. |. gio 81.6 58.42 33 | 44.4 
RGIS Winn, itu aE 49.8 | 81.8 54.59 31.9 | 43.2 
COs al | 50.1 | I.4 59.55 B55. cae 
Weatlington. ..... 4. oss | g2.0. 4 Beg 57.92 4r.8. ‘| ‘52.4 
Ov St) LOUIS... aie ce eck | 50.8 81.4 59.82 ALS - | SES 
EST ei ee ee ee. 60.75 42.9 53.8 
the summers are relatively drier west of the Pearl River, where 
the soils are richer, than in the more typical pine-barrens to the 
eastward. It is easy to imagine how the seasonal distribution of 
rainfall might affect the soils somewhat, as suggested on a pre- 
ceding page, but in this case the loess near the Mississippi River 
must owe its location and character to geological causes rather 
than to any local climatic factors; and it may be that the soil 
itself, perhaps through the vegetation, influences the rainfall 
reciprocally to some extent.* 
VEGETATION 
From the notes taken in the five different years above men- 
tioned a rough quantitative analysis of the vegetation has been 
derived.¢ The 1913 trip has furnished more data than all the 
others combined, partly because of its greater duration (over four 
days), and partly because it was made at a season when the 
number of flowers in the pine-barrens is near its maximum. 
Uae 
* See Bull. Torrey Club 37: 415-416. 1910; Torreya 12: 140-141. 1912; Geol. 
Surv, Ala. Monog. 8: 19, 24. 1913 
T One of the objects of this paper is to show how a botanical reconnoissance 
survey of an essentially homogeneous area of 13,000 square miles can be made in 
less than a week. At this rate a person sufficiently familiar with the flora could cover 
an area the size of New England, New York or Michigan in about a month, or the 
whole United States in five years, even if the country were made up of two or three 
hundred quite dissimilar areas of the size of the one here treated. Or five interested 
Persons could cover the country in one year, or twenty persons (if so many phyto- 
8eographers could be found) in one summer. Even such hasty work brings out some 
fundamental and significant facts not previously known, and if more time can be 
devoted to it the results of course are still more satisfactory. (In view of these 
county or other restricted area, and publishing a list of them, which usually establishes 
no general principles and is therefore of very little scientific value.) 
