INTRODUCTION 111 



and its introduction would be in that case prior to 1789. In 1811 

 Willdenow (Berl. Baumz. ed. 2, 49) described from cultivated 

 plants A. speciosa identical with one of Aiton's varieties of 

 A. nudi flora and the following year Loiseleur Deslongchamps 

 (Nouv. Duhamel. V. 224) described A. rosea also from culti- 

 vated plants. Pursh in 1814 describes as a new species A. 

 arborescens and raises three of Aiton's varieties of A. viscosa 

 and one of A. nudiflora to specific rank. In 1822 D. Don (in 

 Edinb. Philos. Jour. VI. 47) transferred, like Salisbury twenty- 

 six years before, the species of Azalea except A. procumbens to 

 Rhododendron. In this he was followed by Torrey, G. Don, 

 Endlicher, Maximo wicz, Bentham & Hooker and most recent 

 authors, except that Maximowicz, Bentham & Hooker and 

 later authors took up Desvaux's name Loiseleuria for Azalea 

 procumbens. In 1827 Reichenbach, who like the two Dons and 

 Endlicher retained the name Azalea for A. procumbens, proposed 

 the genus Anthodendron (in Moessler, Handb. Gewachsk. 

 I. 244) for A. pontica, A. nudiflora and A. viscosa. G. Don (Gen. 

 Syst. III. 84) in 1834 was the first botanist to subdivide the 

 genus Rhododendron into sections and he proposed the sections 

 Pentanthera and Rhodora with which we are here concerned. 

 After 1814 no new species were added until the year 1855, 

 when A. calif ornica Torr. & Gray (Rh. occidentale Gray) from 

 California was described; it was introduced by Lobb about 1850. 

 The very distinct R. Vaseyi was discovered in 1878 by George 

 Vasey and described the following year by A. Gray; it was in- 

 troduced into cultivation about the same time. In 1891 Greene 

 (m.Pittonia, II. 172) described R. sonomense as a new species, 

 but this is only a form of R. occidentale. In 1892 Otto Kuntze, 

 who took the year 1737 as the starting point for generic nomen- 

 clature and consequently considered Azalea the older generic 

 name, transferred all the species of Rhododendron known to him 

 to Azalea. In 1901 Small (in Bull. Torr. Bot. Club, XXVIII. 

 360) described as a new species A. Candida now referred to 

 R. canescens as a variety, and in 1903 (Fl. S. E. U. S. 883) he 

 described A. oblongifolia and A. serrulata and separated R. 

 Vaseyi as a distinct genus under the name Biltia. In 1913 (I. c. 

 ed. 2, 1356) he adds two new species A. austrina and A. pruni- 

 folia, and in 1914 (in N. Am. Fl. XXIX. 42) A. prinophylla 

 identical with A. rosea Loisel. (R. roseum Rehd.). In 1917 Ashe 



