ENUMERATION OF THE SPECIES 169 



alt. 48,500 feet (No. 5788), alt. 4800 feet (No. 5790), July 1, 1920, 

 alt. 3800 feet (Nos. 5841, 5842), alt. 4000 feet (No. 5843), alt. 4500 

 feet (No. 5844), T. G. Harbison. 



This is the form of the high mountain which replaces the typical tall-growing 

 form at altitudes of from 3800 to 5200 feet. It is a low compact or wide-spreading 

 shrub, usually about 1 m. but occasionally up to 2.5 m. tall. The leaves are some- 

 what smaller and more glaucous. The corolla is rather densely villose and copi- 

 ously glandular-pilose outside, but slightly villose in Nos. 5790, 5841 and 5842; 

 the sepals are usually short, but sometimes, as in Harbison's Nos. G. 34 and D. 42, 

 they are as long as in the type; the style is densely villose on the lower third except 

 in Nos. 62, 655, 5790, 5841, 5842, and 5844, which have a glabrous or nearly glabrous 

 style; the leaves are glaucous beneath, but green in No. 5843. 



What appears to be the same form has been collected near Great Falls, Fairfax 

 County, Virginia, by Mr. W. W. Ashe (see Bull. Torr. Bot. Club, XLVII. 582 [1920]), 

 who kindly sent us a specimen which agrees in every respect with the mountain 

 form described above. 



The variety Richardsonii was introduced into cultivation in 1917 by Mr. H. H. 

 Richardson, who has in his garden at Brookline, Mass., an interesting collection of 

 spontaneous forms of American Azaleas. 



Rhododendron prunifolium Millais, Rhodod. 230 (1917). — Millais & 

 Williams in Rhodod. Soc. Notes, I. 125 (1918) .» 



Azalea prunifolia Small, Fl. S.E.U. S. ed. 2, 1356 (1913) ; in Fl. N. Am. XXIX. 

 44 (1914). 



Slender shrub to 3 m. tall with irregularly whorled branches; young branchlets 

 glabrous, dark purplish red, rarely light grayish brown at the end of the first season, 

 becoming light grayish brown or grayish the second year; winter-buds glabrous, 

 light brown or reddish brown, with broadly ovate scales rounded and mucronulate, 

 sometimes nearly aristate at the apex and ciliolate. Leaves elliptic, or sometimes 

 obovate to oblong, acute or short-acuminate and gland-tipped, cuneate or broadly 

 cuneate at base, 3 to 10 cm. or occasionally to 13.5 cm. long and 1.7 to 4 cm. broad, 

 ciliate, dark or bright green, glabrous above except the slightly villose midrib and 

 dull green, very rarely sparingly strigillose, lighter green beneath and sparingly 

 strigose on the midrib and sometimes on the veins, midrib and secondary veins 

 often rather prominent beneath and light-colored, slightly impressed above; peti- 

 oles 3 to 6 mm. long, glabrous or rarely sparingly strigose. Flowers about the 

 middle of July in 4- to 5-flowered umbel-like clusters; pedicels about 5 mm. long, 

 hirsute; sepals semi-orbicular to ovate, about 1 mm. long, long-ciliate; corolla 

 funnel-form, crimson, the tube gradually widened above the middle, 2 to 2.5 cm. 

 long, glabrous or sparingly hirsute, pubescent inside, the lobes broadly ovate, 

 abruptly acuminulate, about 1.5 cm. long and 0.9 to 1.3 cm. broad and more or less 

 finely villose and sometimes slightly glandular-pilose outside; stamens much ex- 

 serted, nearly three times as long as the tube, 5 to 6.5 cm. long, villose on and 

 below the middle; anthers 2 to 3 mm. long, ochraceous; style much exceeding the 

 stamens, about 8 cm. long, glabrous, purple above; ovary covered with long se- 

 tose, glandless hairs. Capsule ovoid-oblong, about 2 cm. long, strigose and finely 

 puberulous. 



1 Rhododendron prunifolium Forbes, Hort. Woburn, 91 (1833), is a nomen nudum 

 and cannot invalidate Millais' combination. 



