JOURNAL 



OF THE 



ARNOLD ARBORETUM 



OLT7ME 



JANUARY. 1921 Number 3 



BOTANICAL RECONNAISSANCE OF SOUTHERN ILLINOIS 



Ernest J. Palmer 



Most of the collecting season of 1919 was spent by the writer in making 

 a botanical reconnaissance of several of the southern counties of Illinois 

 for the Arnold Arboretum. The purpose of this extensive field work 

 was to make as complete a collection as possible of the ligneous plants, 

 noting the conditions under which they grow; and incidentally to observe 

 the physiography of the region, the influence of its various phases upon 

 the flora, and the relation of this to the forests of the Gulf coastal plain 

 on the south and to the prairies to the north of this region. In addition 

 to the collection of the woody plants for the Arnold Arboretum a large 

 series of the herbaceous species was taken for the Missouri Botanical 

 Garden, in the herbarium of which institution a full suite of both is now 



preserved. 



Most of the collecting was done in the two southernmost scries of 

 counties, and in those bordering the Ohio River on the cast side as far 

 north as the mouth of the Wabash River, or approximately in the region 

 south and east of a line drawn from Cape Girardeau to Grayville. Sev- 

 eral excursions were made beyond this area in Illinois and in the adjoin- 

 ing states of Missouri, Kentucky and Indiana, where physiographic con- 

 ditions are, of course, quite similar. 



Field work was carried on from early in April until the end of June, 

 and in fall from the middle of September to the last week in October. 

 The spring and early summer of 1919 was extremely wet in this section; 

 and following a drouth of several weeks in mid-summor there ensued a 

 period of very heavy and almost continuous rain in October. There 

 were very few days free from clouds and rain in May, and twenty-one 

 days show a record of rainfall during some part of the twenty-four hours. 

 After the middle of October the rain fell so continuously that little could 

 be accomplished, and several contemplated trips had to be abandoned. 

 Under these conditions travel, especially in the low and swampy parts of 

 the region, was disagreeable and sometimes impossible; and as no arti- 

 ficial heat was available the greatest difficulty was experienced in drying 

 specimens. 



