[161] U. S. D. A. Plant Immigrants No. 113:920. 1911.
[162] Ibid. No. 114:929. 1911.
[163] Wickson, E. J. Cal. Fruits 308. 1889.
[164] Gregory, C. T. Cornell Bul. 365:219-220. 1915.
[165] Trait. Arb. Fr. 35. 1807.
[166] Darwin Ans. and Pls. Domest. 2nd Ed. 2:217. 1893.
[167] Hedrick, U. P. Science 37:917. 1913.
[168] U. S. D. A. Plant Immigrants No. 106:858. 1915.
[169] Trans. Hort. Soc. Lond. 3:1. 1820; 4:396. 1822.
[170] See Duhamel Traite Arb. Ed. 2, IV: 112. 1809; Seringe in DC. Prodr. II: 531. 1825; Reichenback Fl. Ger. Exc. 647. 1830-32.