_Prunus simonii_ has been widely grown in America both for its fruits and as an ornamental, but it cannot be said that it has become popular for either purpose and only one variety of the species is now under cultivation. As a food product the plums lack palatability and as ornamentals the trees are subject to too many pests. _Prunus simonii_ has been successfully hybridized with _Prunus triflora_ and as secondary crosses its blood has been mingled with that of some of the native species as well. Most of its hybrid offspring have more value than the parent, nearly all of them lacking its disagreeable taste. According to an article published in _Revue Horticole_[110] a new form of the _Prunus simonii_ was produced in 1890 from a bud sport, the fruit of which is elongated, a little cordate, slightly unequal, and grooved on one side. So far as can be learned this sport has no very decided merits as a horticultural plant. =10.= =PRUNUS AMERICANA= Marshall [Illustration: _PRUNUS AMERICANA_] =1.= Marshall _Arb. Am._ 111. 1785. =2.= Eaton and Wright _N. Am. Bot._ 377. 1840. =3.= Torrey and Gray _Fl. N. Am._ =1=:407. 1840 (in part). =4.= Torrey _Fl. N. Y._ =1=:194. 1843 (in part). =5.= Emerson _Trees of Mass._ 449. 1846. =6.= Nuttall _Silva_ =2=:19. 1846. =7.= Darlington _Fl. Cest._ Ed. =3=:72. 1853. =8.= Torrey _Pac. R. Rpt._ =4=:82. 1854. =9.= Curtis _Rpt. Geol. Surv. N. C._ 56. 1860. =10.= Ridgway _Proc. U. S. Nat. Mus._ 65. 1882. =11.= Sargent _10th Cen. U. S._ =9=:65. 1883 (in part). =12.= Watson and Coulter _Gray’s Man._ Ed. =6=:151. 1889 (in part). =13.= Coulter _Cont. U. S. Nat. Herb._ =2=:102. 1891. =14.= Sargent _Silva N. Am._ =4=:19, Pl. 150. 1892. =15.= Rydberg _Cont. U. S. Nat. Herb._ =3=:156. 1895. =16.= _Ibid._ =3=:494. 1896. =17.= Waugh _Vt. Sta. Bul._ =53=:59. 1896. =18.= Ibid. _Vt. Sta. An. Rpt._ =10=:100. 1896-7. =19.= Chapman _Fl. Sou. U. S._ 130. 1897. =20.= Bailey _Ev. Nat. Fr._ 182, fig. 1898. =21.= Waugh _Vt. Sta. An. Rpt._ =12=:231. 1899. =22.= Mohr _Cont. U. S. Nat. Herb._ =6=:551. 1901. =23.= Bailey _Cyc. Am. Hort._ 1448 fig. 1901. =24.= Rydberg _Fl. of Colo._ 193. 1906. Tree attaining a height of thirty feet, slow but strong in growth, often shrubby; trunk thick, sometimes a foot in diameter, short, bearing the head at three to five feet; bark one-half inch thick, dark grayish-brown, outer surface rough, shaggy with large scales, with age becoming smoother, giving a characteristic aspect; branches spreading, crooked, long, rigid, but often pendulous at the extremities, more or less thorny, with lateral, spinescent branchlets; branchlets light green, usually glabrous, sometimes much or little tomentose, at first becoming brownish and later tinged with red; lenticels numerous, large and distinct.