ROSACEAE. 



105 



Aroma. Chokeberry. 

 (Family Rosaceae). 



Shrubs: deciduous. Twigs mod- 

 erate, roundish, glabrous, brown: 

 D I pith moderate, rounded, pale, con- 

 tinuous. Buds solitary, sessile, ob- 

 long, flattened and appressed, with 

 about 5 often abruptly short- 

 pointed more or less glandular- 

 denticulate scales. Leaf-scars al- 

 ternate, U-shaped, low: bundle- 

 traces 3: stipule-scars lacking. 

 (Pyrus). 



Aronia, like Sorbus, is segre- 

 gated from Pyrus by the less con- 

 servative botanists and retained in 

 that genus by those who are more 

 conservative. In common with 

 the firethorn and several other 

 diverse types, it has found lodg- 

 ment at one time or other in the 

 genus Mespilus, now by common 

 consent restricted to the German 

 medlar, M. germanica. The only winter-character reference, 

 to A. arbutifolia, is Schneider's f. 147. 



In curious contrast with the absence of apple-pear hy- 

 brids, several crosses are known to occur between mountain- 

 ash (Sorbus) and chokeberry (Aronia) variously considered 

 to be distinct genera or sections of Pyrus: for these the 

 generic name x Sorbaronia may be used appropriately. 



1. Twigs and buds glabrous. 



(Black chokeberry). (1). A. melanocarpa. 

 Twigs more or less woolly. 2. 



2. Buds quickly glabrous. (Purple c.) A. atropurpurea. 

 Buds somewhat woolly. (Red chokeberry). A. arbutifolia. 



