170 
SIMARUBACEAE. 
AILANTHUS. 
Tree of Heaven. 
(Family Simarubaceae). 
Rather smooth-barked loosely 
branched trees with persistently 
prominent lenticels: deciduous. 
Twigs coarse, somewhat 3-sided: 
pith large, homogeneous, round- 
ish, becoming colored. Buds sol- 
itary, sessile, hemispherical, rela- 
tively small, with 2 or 4 exposed 
scales, the end-bud fallen, leaving 
a large scar. Leaf-scars alter- 
nate, cordately  elliptical-shield- 
shaped, slightly raised, large: 
bundle-traces about 9: _ stipule- 
sears lacking. 
Winter-character references:— 
Ailanthus glandulosa. Blakeslee 
& Jarvis, 334, 524, pl.; Bosemann, 
61; Hitchcock (3), 9; Otis, 170; 
Schneider, f. 35, 99; Shirasawa, 
236; Ward, 1:118, f. 59. 
Like Gymnocladus, Ailanthus 
offers exceptionally good opportunities for recognizing that 
year after year the branches of certain trees are continued 
by development of axillary or lateral buds, the tip of each 
year’s growth disappearing early by a clean-cut abscission. 
Mr. Swingle, after reviewing the early European history 
of Ailanthus, shows that the commonly cultivated species 
should be called A. altissima, in the Journal of the Washing- 
ton Academy of Sciences, of August 19, 1916. 
1. Twigs prickly. 
2. Twigs puberulent. 
Twigs glabrescent. 
A. Vilmoriniana. 
(1). A. glandulosa. 
A. glandulosa pendulifolia. 
