312 BOTANICAL GAZETTE. [ December, 
Development of cork-wings on certain trees. III. 
EMILY L. GREGORY. 
(WITH PLATE XXV.) 
Of the genus Euonymus, the species now known as alatus, 
formerly described as Celastrus alatus Thunb., presents the 
most marked and striking example of what is known as cork- 
wings. The first important consideration on taking up the 
study of the wing in this genus is, that we have no longer to 
do with large trees, but with small ones and shrubs. One 
of our own native varieties, E. Americanus var. obovatus, 
Gray describes as trailing with rooting branches. Another 
species has small rootlets scattered over the branches. 
Closely connected with this fact is another of equal import- 
ance, that is, the lasting nature of the epidermis, or the length 
of time that some part of the surface of the stem performs the 
function of assimilation. Of the thirteen kinds of Euonymus 
