Ainus BETULACEAE Carpinus 



Key to the Genera 



Nut without leaf-like involucre, small and compressed 1. Ainus 



Nut with a leaf-like involucre. 



Fr. in pendulous spikes 2 . Carpinus 



Fr. in dense clusters: staminate catkins formed in the autumn 3. Corylus 



1. Ainus B. Ehrh. Alder ||^M (Ch'i Mu Shu) 

 Staminate catkins drooping, much longer than the erect pistillate ones: fr. a very 

 narrowly winged nutlet, developing in the axils of woody persistent scales of an 

 oblong cone. 30 species, widely distributed in the northern hemisphere; 7 in China. 

 (The Latin name.) 



Key to the Species 



Lvs. narrow-elliptic to oblong-lanceolate, without prominent cross-veins 



between the lateral nerves: frtg. cones 12-15 mm. long \. A. japonica 



Lvs. elliptic to obovoid, with cross-veins between the lateral nerves 



prominent beneath : frtg. cones 20-25 mm. long 2. A. trabeculosa 



1. Ainus japonica Sieb. & Zucc. Japanese Alder ^]f (Ch'ih Yang; Red Poplar) 

 (R.M.138). Tree, to 25 m.; fls. II— III ; fr. X. Northeastern Asia; locally in Che., 

 Ku. Planted, ornamental. Fig. 52. 



2. Ainus trabeculosa Hand.-Mazz. (A. jackii Hu) (R.M.138). Tree, to 10 m.; fls. 

 II— III ; fr. IX-X. China; locally in An., Che., Hun., Ki., Ku. Swampy woodland. 



2. Carpinus Linn. Hornbeam =f&MM (Ch'ien Chin Yu Shu) 

 Lvs. more or less 2-ranked: both staminate and pistillate catkins pendulous: fr. 

 a ribbed nutlet in the axil of a large leaf-like bract. About 20 species in the 

 northern hemisphere; 12 in China. (The Latin name.) 



Key to the Species 



a. Frtg. bracts densely imbricated, ovate, completely covering the 



nutlet : lvs. with 15-20 prs. of veins, cordate \. C. cordata 



aa. Frtg. bracts laxly arranged, oblique, not completely covering the 

 nutlet : lvs. with 10-15 prs. of veins, 

 b. Frtg. bracts distinctly lobed at the base, outer margin obtusely 

 toothed. 

 Lvs. ovate-oblong to lanceolate: bracts about 5mm. apart. 2. C. viminea 

 Lvs. ovate to ovate-oblong : bracts closer. 



Lvs. 4-5 cm. wide: base rounded or nearly cordate 3a. C. laxiflora 



var. maerostachya 

 Lvs. 2-3 cm. wide; base rounded, obtusa or broadly cuneate. 3b. C. laxiflora 



var. davidii 



bb. Frtg. bracts with inner margins not distinctly lobed at the 



base, slightly indexed : lvs. ovate 4. C. turczaninowii 



1. Carpinus cordata Blume T^Hc (Ch'ien Chin Yu; Thousand-coin Elm) (R.M.141). 

 Tree, to 15 m. Northeastern Asia; locally in An. Mixed forest. 



2. Carpinus viminea Wall. W&M (Lei Kung Li; God-of-thunder Oak) (Mete. F. 49). 

 Tree, to 10m.; fr. VII-IX. Eastern Asia; locally in An., Ki. Mixed forest. 



3a. Carpinus laxiflora (S. & Z.) Blume var. maerostachya Oliv. jRQftMl (C. fargesii 

 Franch.) (Hsi Ssu Li; Fine-grained Oak) (R.M.140). Tree, to 16 m. Central and 

 western China; locally in An., Che., Ki., Ku. Mixed forest. 



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