lU JOURNAL OF THE ARNOLD ARBORETUM [vol. ii 



men collected by Dr. Edward Palmer at Lerios, Coahuila. Tlie Big-tree 

 Plum has thick leaves usually broad and rounded at base with more or less 

 prominent reticulate veinlets, villose-pubescent on the midrib and veins 

 below, glabrous pedicels and globose or rarely short-oblong dark red fruit 

 covered with a bluish bloom, the stone nearly round to obovoid, turgid, 

 usually pointed at base and rounded at apex. 



Pruniis mexicanay which is distributed through Arkansas to southeastern 

 Kansas, eastern Oklahoma, western Louisiana, and eastern and southeast- 

 ern Texas into northwestern Mexico, and occurs in eastern Louisiana, never 

 produces suckers from the roots, and is a tree up to 14 m, in height with a 

 single trunk often 3 dm. in diameter, covered with dark, nearly black or 

 light gray bark, exfoHating in plate-like scales on young stems and large 

 branches, and becoming rough and furrowed on old trunks. With more 

 knowledge of the Big-tree Plum than I had when I described it in 1911 it 

 seems better to consider varieties of P. mexicana the related species which 

 I described at that time as P. reticulata^ P. polyandra and P, Julionensi^. 

 These three then become: 



Prunus mexicana var. reticulata, n. var. — Prunus reticulata Sargent 

 in Trees and Shrubs, ii. 151, t. 162 (1911). 



Differing from the type in its thicker leaves more often narrowed at base, 

 with more prominent reticulate veinlets, pubescent pedicels, smaller glo- 

 bose fruit ripening late in September or in October, with thin bitter astrin- 

 gent flesh, and dark deeply furrowed bark. 



Distribution. Uplands and along the margins of river-bottom lands; In the 

 neighborhood of Dallas and of Sherman, Grayson County, northern Texas. 



Prunus mexicana var. polyandra, n. var. — Prunus polyandra Sargent 

 in Trees and Shrubs, ii. 155, t. 164 (1911). 



DifTering from the type in the narrower base of the leaves, the more numer- 

 ous stamens (up to 36), in its earlier ripening fruit with an obovoid com- 

 pressed stone pointed at apex, and gradually narrowed and acute at base. 



Distribution. Rich woods, Fulton, Hempstead County, Arkansas. 



Prunus mexicana var. fultonensis, n. var. — Prunus fultonensis Sar- 

 gent in Trees and Shrubs, ii. 248 (1913). 



Differing from the type in its thinner leaves i)ubesccnt below over the 

 whole surface, with more obscure reticulate veinlets, and in its smaller 

 dark bluish purple fruit ripening in June, with thin flesh and a compressed 

 stone pointed at apex and gradually narrowed and acute at base. 



Distkibution, Ilieh woods near Fulton, Hempstead County, Arkansas. 



Prunus virginiana L. Attempts have been made by different authors to 

 separate the Choke Cherry of North America into several species, but a 

 careful examination of the large amount of material preserved in the her- 

 barium of the Arboretum and a study of the trees growing in a considerable 

 part of the region which the Choke Cherry inhabits and in cultivation fails 



to show characters in the different forms sufficiently stable to justify their 



