94 



ROSACEAE. 



Spiraea. 

 (Family Rosaceae). 



Shrubs, usually low and little 

 branched or else with wandlike 

 branches: deciduous. Twigs ter- 

 ete or angled from the nodes, often 

 very slender, more or less zig-zag: 

 pith small, roundish, continuous. 

 Buds small, solitary or in a few 

 cases collaterally multiplied, ses- 

 sile, globose to subfusiform, mostly 

 with some half-dozen exposed 

 scales. Leaf-scars alternate, half- 

 round or crescent-shaped, minute, 

 often much raised: bundle-trace 1: 

 stipule-scars not evident. 



Spiraea, like Pyrus and Prunus, 

 is a genus which has been very 

 differently denned by different 

 botanists, for some of whom it in- 

 cludes the plants here considered 

 under the genera Neillia, Physo- 

 carpus, Sorbaria and Stephanan- 

 dra. The most concise winter-key to any considerable num- 

 ber of its species is that of Bosemann, which treats it in this 

 broader and older sense. The comparatively few species that 

 enter into ordinary American planting? and are considered 

 here differ for the most part in several distinctive ways, and 

 their buds belong to several unmistakable types. 



Winter-character references: 8. ariaefolia. Bosemann, 

 76. 8. betulae folia. Shirasawa, 244, pi. 4. 8. cana. Schnei- 

 der, f. 175. X 8- cantoniensis. Shirasawa, 246, pi. 4. 8. 

 chamaedry folia. Bosemann, 75. 8. crenata. Schneider, f. 

 174. 8. discolor. Schneider, f. 179. 8. hypericifolia. Bose- 

 mann, 77; Schneider, f. 175. 8. japonica. Shirasawa, 274, pi. 



