526 The Trees of Great Britain and Ireland 



Carpinus and Ostrya are very similar in foliage ; and the following key, based 

 upon the characters of the leaves and branches (Plate 201), distinguishes all the species 

 of both genera which are in cultivation in England. Carpinus laxifiora, though not 

 yet introduced, has been included, as it has been much confused with the other 

 Japanese hornbeams. 



Key to Carpinus and Ostrya 



I. Leaves not exceeding 2 inches in length. 



1. Carpinus orientalis, Miller. South-eastern Europe, western Asia. 



Leaves i\ inch long, acute, deeply plicate. 



2. Carpinus polyneura, Franchet. Central China. 



Leaves 2 inches long, acute, smooth and only slightly plicate. 



n. Leaves exceeding 2 inches in length. 



A. Leaves lanceolate. 



3. Carpinus japonica, Blume. Japan. 



Leaves about 4 inches long, much longer in proportion to their width than 

 in the other species, with numerous (eighteen to twenty-four pairs) nerves. 



B. Leaves ovate, acute at the apex. 



4. Carpinus yedoensis, Maximowicz. Central China. Cultivated in Japan. 



Leaves 2\ inches long, rounded at the base, with conspicuous bands of 

 appressed pubescence on the upper surface. Branchlets pilose. 



C. Leaves ovate, acuminate at the apex. 

 ^^ Leaves deeply cordate at the base. 



5. Carpinus cordata, Blume. China, Korea, Manchuria, and Japan. 



Leaves 4 to 5 inches long, broad in proportion to their length, with fifteen to 

 twenty pairs of nerves, 



** Leaves rounded or only slightly cordate at the base. 

 t Under surface glabrous between the tterves. 



6. Carpinus laxiflora, Blume. China, Japan. 



Leaves 2\ inches long, rounded at the base, abruptly contracted into a very 

 long acuminate apex. Branchlets with scattered long hairs. Buds minute, 

 ^ inch long. 



7. Carpinus Betulus, Linnaeus. Europe, western Asia. 



Leaves 3 inches long, slightly cordate at the base, turning yellow in autumn. 

 Branchlets with scattered long hairs. Buds fusiform, ^ to ^ inch long. 



8. Carpinus caroliniana, Walter. North America. 



Leaves as in C. Betulus, but turning red in autumn. Branchlets with 

 scattered long hairs. Buds ovoid, \ inch long. 



ft Under surface pubescent between the nerves. 



9. Ostrya carpinifolia, Scopoli. Southern Europe, Asia Minor, Syria. 



Leaves 3 inches long, not velvety to the touch above, rounded at the base. 

 Branchlets with dense appressed pubescence. 



