U)8 



I^nnnis ji/di/i/a. representing the endemic element iilonu tlie 

 hike. 



A coiniiarisdii with the Hnra of the sand-iiilis of Nebraska, 

 on the otlier liand. shows some striking similarities. Kydherg 

 ('95) lists 85 species as characteristic of the sand-hill region, 

 and of these, 15. or nearly one half, grow also in the central- 

 Illinois sand region, and this includes a numhei- of the most 

 abnudant species. Of the IS.S species ennmerated in t:his paper. 

 75. or 40 percent, are included also in Kydberg's list. 



It is evident fi-ointhe preceding paragraphs that as a whole 

 the flora is essentially western in its relationships. Its position 

 within the Prairie province, as definetl by Pound and t-lements, 

 can not be (juestioued, and the region may well be regarded as 

 an isolated portion of the sand-hill division of the Prairie prov- 

 ince, formed under ])eculiar conditions, but closely resemi)ling 

 the main body in its ecology and vegetation. 'J'he species found 

 only in the black-jack oak forest are almost entirely eastern in 

 their distribution, and have usually a wide range through the 

 .state in different plant as.sociations. 



Of especial interest from a phytogeographical stand[>()iiit 

 are Cristdfclhi JdiHi-sii and Lisiiiicir/i'i xjxtfluilittd. This is 

 the first report of their occurrence in Illinois, and. so far 

 as known, at any station east of central Nebraska. The form- 

 er ranges through the sand-hill region from Neln-aska south 

 into Texas, and according to Britton's Manual into Louisiana. 

 In Nebraska it lives in almost precisely the same conditions as 

 in this state; that is, in the bottoms of Idowonts. where there 

 is a comparatively rapid shifting of the sand In 19(18 it was 

 fouml in i)nt a single lilowout near Havana, and the total num- 

 ber of individuals was i)robal)ly less than Hve hundred. In 1904 

 it had spread to two other blowouts in the .same field, and it 

 was also found in great profusion in a large blowout about 

 ten miles northeast of Havana. Li si/Kirc/ld sji/i//iii/ti/)i. de- 

 scribed in bS9() from the Plack IHlls. i-anges. according to 

 Britton, from Nebraska to Montana and the Northwest Terri- 

 tory. Kydberg's original plants I ■9() ) grew on dry hilltops, a 

 habitat paralleled by its growth in Illinois in the binich-gra.ss 



