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 
seales. 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 defined 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:—S. ariaefolia. Bosemann, 
76.—S. betulaefolia. Shirasawa, 244, pl. 4.—S. cana. Schnei- 
der, f. 175.—>» 8S. cantoniensis. Shirasawa, 246, pl. 4.—S. 
chamaedryfolia. Bosemann, 75.—S. crenata. Schneider, f. 
174.—S. discolor. Schneider, f. 179.—S. hypericifolia. Bose- 
mann, 77; Schneider, f. 175.—S. japonica. Shirasawa, 274, pl. 
