INTRODUCTION 113 



ary; the most southern species are R. serrulatum which reaches 

 middle Florida and R. canescens which extends in Texas nearly as 

 far south. In the North R. canadense is found as far north as 

 Labrador. The western limit of the Atlantic Azaleas runs from 

 southern Quebec to northeastern Ohio, then through southeast- 

 ern Indiana, extreme southeastern Missouri, central Arkansas and 

 extreme eastern Oklahoma to the coast of eastern Texas. The 

 greatest development of the group is on the Appalachian 

 Mountains and as the centre of segregation we must consider 

 Georgia, where eight species, half of all American species, occur. 

 The Azaleas are shrubs from one half to two metres or rarely 

 to 7 metres in height and are essentially inhabitants of the 

 temperate deciduous forest; they are mostly moisture and shade 

 loving shrubs and most species are found on the wooded slopes 

 of hills and mountains growing in scattered individuals inter- 

 mingled with other shrubs and trees. Like most Ericaceae they 

 are calciphobous and therefore are absent from limestone 

 regions, although R. roseum is found in western New York and 

 R. oblongifolium in Oklahoma on limestone soil. In spring when 

 in bloom they form a most conspicuous feature of the woods, 

 particularly species like R. calendulaceum on the mountains 

 from Pennsylvania to Georgia with its brilliant orange or scarlet 

 flowers and R. speciosum in Georgia with bright red or scarlet 

 flowers; also R. nudiflorum, R. roseum and R. canescens with 

 white to pink flowers are conspicuous, the latter being widely 

 distributed in the woods of the southern coastal plain. The late 

 flowering species, as R. viscosum and R. serrulatum, are less showy 

 but deliciously fragrant and inhabit chiefly swamps and moist 

 woods of the coastal plains from New England to Louisiana, 

 though the northern species R. viscosum also grows on the 

 mountains. The related R. arbor escens with white and fra- 

 grant flowers is likewise a mountain plant. Only R. atlanticum 

 is a predominant feature over large areas as it grows in open 

 pine woods of the coastal plain chiefly in North and South 

 Carolina. Most species have a wide distribution, particularly 

 R. nudiflorum, R. canescens, R. viscosum and R. serrulatum', 

 others, like R. speciosum, R. oblongifolium and R. atlanticum, 

 occupy an area not more than about two to three hundred 

 miles in length and R. Vaseyi, R. alabamense and R. pruni- 

 folium are more limited in distribution. 



