38 



may extend their roots to depths of from 2 to 5 meters. 1 

 Goff 2 reports grape roots at 13 feet (4.1 m. ) and roots 

 of a seven-year-old apple tree at 9 feet (2.7 m. ). Corn 

 roots are reported at 7 feet (2.1 m. J by iing3 and by 

 Georgeson and Payne 4 * The latter authors report the 

 roots of cow-pea at 6 feet (1.8 rn.O 5 * According to 



l7 Gannon,- Car. Inst, of Wash., Yearbook y.: 

 62 (lylO); Car. Inst, of Wash., Pub. 131 . pp. 60, 75, 77, 

 80, 81, 82, 92 (1911 J. On deep roots of desert plants 

 see: Yolkens,- Flora der agypt.-arab. Wuste, pp. 

 (1887); Aitchinson,- Trans. Linn. 3oc. (2) g: (1887); 

 Schinz,- Coloniales Jahrb. 6: (1893); Warming, - 



Oecology, pp. 117-118 ( 1909 ) ; Cannon,- Car. Inst, of 

 Wash., Yearbook, 10: 61 (1911). On deep roots of dune 

 plants see Warming loc . ci t . supra and Vid. Lfeddel. 

 naturh. For., Kjobenhavn : (1891). 



2. Wise. Agr. Exp. Sta., Report 189 7 : 286-298. 



3. Wise. Agr. Exp. Sta., Report 1891 : 131-134. 



4. Kans. Agr. Exp. Sta., Bull. J75: 212-222 

 (1898). 



5. loc. cit. 



