116 JOURNAL OF THE ARNOLD ARBORETUM [vol. ii 



Prunus virginiana var. demissa f. pachyrrhachis, n. comb. — Prunns 



demissa var. Nuttallii f. pachyrrhachis Koehne in Mitt. Deutsch. Dendr. 

 Gesell. XX. 236 (1911). — Padus valida Wooton & Standley in Contrib. 

 U.S. Nat. Herb. xvi. 134 (1913), 



Differing from var. demissa in the cuneate or rounded base of the leaves 

 viUose pubescent below on the midrib and veins, in the stouter pubescent 

 rachis and pedicels, and in the pubescent branchlets usually becoming 

 glabrous at the end of their first season. 



Leaves oval or slightly obovate, acute or abruptly short-pointed at apex, 

 rounded at b 



green 



drib 



2.5-3.5 cm. wide; petioles stout, pubescent, glandular at apex, 1-L5 cm. 



in length; leaves of a vigorous shoot 10-11 cm. long and 5-6 cm. wide. 



Flowers not seen. Mature rachis and pedicels stout, densely pubescent. 



Probably a shrub with usually stout branchlets finely pubescent during 



their first and second seasons, and stout acute winter-buds 8 nun. or 9 mm. 

 long. 



Type Locality. Canyons. Kingston, Sierra County, New Mexico, at an alti- 

 tude of Z^im m., August 24, 1904, 0, B, Metcalfe (No. 1243 In Herb. Nat. Mus.). 



The type of this form is well distinguished by its stout pubescent branch- 

 lets, large winter-buds, thick pubescent rachis and pubescent pedicels. 

 Flowers of the type have not been seen, but the fruit and its stone are sim- 

 ilar to those of Prunus virginiana. The other Choke Cherries from New 

 Mexico, Padus -pnmicea, P. calophylla and P. mescaleria Wooton & Stand- 

 ley (in Contrib. U.S. Nat. Herb. xvi. 133, 134 [1913]), varying somewhat 

 in the shape of their leaves and in the amount of their pubescence, have 

 branchlets more or less pubescent and afford no characters by which they 

 can be satisfactorily separated. The type specimen of Padus jmmicea 

 (No. 563903 in Herb. Nat. Mus.) is a sterile branch with slightly pubescent 

 leaves and branchlets. Another specimen (No. 737183 in Herb. Nat. Mus.) 

 referred to this s])ecies from the same locality has more pubescent leaves 



pubescent 



forma 



pachyrrhachis. The type specimen of Padtis calophylla (No. 562677 in 

 Herb. Nat. Mus.) has narrow-elliptic pubescent leaves, a slender puberulous 

 rachis and branchlets; another specimen referred to this species (No. 686679 

 in Herb. Nat. Mus.) has broad-oval leaves glabrous with the exception of 

 small axillary tufts of pale hairs below, and a slender puberulous rachis and 



branchlets. 



Pad 



Nat. Mus.) has slightly pubescent leaves, a glabrous rachis and puberulous 

 branchlets. Although perhaps most closely related to the form pachyrrha- 



species 



transition 



Their connection with P. 



virginiana var. demissa is shown by a sterile specimen (No. 6042 in Herb. 

 Arnold Arboretum) collected near Valentine, Cherry County, in northern 

 Nebraska by the Reverend John Bates, with broad-oval or obovate leaves 



pubescent below and distinct.lv nubcsr-pni lir-anrTilets. ahH Kv n sn^r^Imon 



