ERICACEAE 115 



LEDUM. Labrador Tea. 



Small evergreen bog-shrubs with slender terete twigs; 

 somewhat 3-sided brown continuous pith; alternate minute 

 crescent-shaped or 2-lobed leaf-scars with a single bundle trace; 

 no stipule-scars; minute round sessile lateral buds and larger 

 ovoid terminal buds with several exposed scales; elliptical- 

 oblong leaves, revolute and rusty-tomentose beneath in the 

 eastern species; small open perfect nearly polypetalous white 

 flowers in short terminal clusters; and small many-seeded 

 capsules dehiscent at the base. 



Leaves subelliptical, rather broad. L. groenlandicum. 



Leaves linear, narrow. L. palustre. 



RHODODENDRON. 



Evergreen or deciduous 1 shrubs or small trees with hard 

 brownish wood with minute ducts, rather more crowded in 

 spring, and fine medullary rays; rounded slender or stout 

 twigs; rounded or angular continuous pith; alternate crescent- 

 shaped or transverse leaf-scars with 1 bundle-trace; no stipule- 

 scars; ovoid sometimes very large buds with a number of 

 exposed scales; entire or ciliate lanceolate petioled leaves; 

 perfect showy clustered mostly gamopetalous flowers; and 

 small more or less elongated capsules. Azalea and Rhodora are 

 considered separate genera sometimes. 



1. Leaves thick, evergreen. (Rhododendron). 2. 

 Leaves thin, mostly deciduous. (Azalea; Rhodora). 4. 



2. Leaves tapering to apex and base: pedicels glandular. 3. 

 Leaves rounded at ends; pedicels downy. R. catawbiense. 



3. Flowers rosy-white, spotted. R. maximum. 

 Flowers white. . R. maximum album. 

 Flowers purplish. R. maximum purpureura. 



4. Bud-scales two to four. 5. 

 Bud-scales many. 6. 



5. Leaves deciduous. R. indieuin. 

 Leaves evergreen. R. Simsii. 



