xxxviii KEYS LEAVES ALTERNATE 



418. Twigs with narrow low ribs. 419. 

 Twigs deeply corrugated or grooved. 420. 



419. Twigs sharply zig-zag. p. 152. Coronilla. 

 Twigs not conspicuously zig-zag. p, 154. Caragana. 



420. Leaf-cushion without prominent ribs. p. 146. Cytisus. 

 Leaf-cushion 3-ribbed. p. 147. Genista. 



421. Freely resiniferous when cut. p. 184. Pistacia. 

 Without free-flowing sap or resin. 422. 



422. Scales 2: bundle-trace C-shaped. p. 303. Diospyros. 

 Without this combination of characters. 423. 



423. Buds not scaly: leaf-scars round. p. 138. Ceratonia. 

 Without this combination of characters. 424. 



424. Leaf-scars usually deltoid, as high as broad. 425. 

 Leaf-scars usually broader than high. 432. 



425. End-bud not enlarged if present. 426. 



End-bud distinctly larger than the lateral buds. 430. 



426. Twigs glabrescent. 427. 



Twigs sparingly pubescent. 429. 



427. Buds slightly glaucous: twigs red. p. 269. Elliottia. 

 Buds not glaucous. 428. 



428. Twigs reddish, becoming buff. p. 270. Zenobia. 

 Twigs brown: buds very glossy. p. 288. Oxydendrum. 

 Twigs gray. p. 286. Pieris. 



429. Twigs moderate: evergreen or deciduous, p. 286. Pieris. 

 Twigs very slender: evergreen. p. 291. Pernettya. 



430. Outer scales of end-bud shorter than the bud. 431. 

 Outer scales as long as the bud. p. 268. Clethra. 



431. Bark shredding: capsules bristly. p. 275. Menziesia. 

 Without this combination. p. 272. Rhododendron. 



432. Soft-wooded or aromatic, deciduous, quickly 



branching. 433. 

 Without this combination of characters. 435. 



433. Buds solitary. 434. 



Buds often superposed: with stipules. p. 176. Securinega. 



