No. 423-] NORTHERN. POLYPETALOUS FLOWERS. 225 
mark an advance upon the Rosales in that the cyclic arrangement 
prevails and there is an imperfect union of the carpels. The 
families of the Sapindales differ widely and have been divided 
into numerous subseries. |The Empetracez, Buxacez, and 
Limnanthacee are represented in the northern states by only 
four species. The flowers are small, and probably partly 
primitive and partly reduced. 
The Anacardiaceze and a number of allied families are of much 
interest, as the inflorescence has been but little modified by 
insects. The species are mainly trees and shrubs with green, 
white, and greenish-yellow flowers, which are visited by- Diptera 
and the smaller and less-specialized Hymenoptera. The Ana- 
cardiaceze, or sumac family, have small, regular flowers in dense 
panicles. Both the sepals and petals are present, but the flowers 
are greenish or greenish yellow, though sometimes tinged with 
red as in the smoke tree.: They secrete honey and are attractive 
to flies and Andrenide. On the smoke tree, Cotinus cotinus 
(Rhus cotinus), there have been collected six flies, one beetle, 
and ten Hymenoptera. . The species tend to become dicecious, 
and Cofzmus cotinus (Rhus cotinus) shows all transitional stages - 
between staminate, hermaphrodite, and pistillate flowers. While 
the visits of insects have not developed bright colors, the leaves 
of Rhus radicans and the fruit of Re aromatica are red in 
autumn, and the wood of several species is orange yellow. 
R. glabra sometimes has the whole or a part of the flower 
cluster changed into-small leaves. 
The various species of Illicaceze, or holly, have small white 
flowers, with freely exposed honey. . The berries of Merx verti- 
ciliata are bright red, or rarely yellow, or even white. |The visit- 
ors are similar to those of the preceding family. The Celastraceze 
is composed of trees and "abes with small, — green, yellow, 
and purple flowers. | 
Five species are. green, | theod edis ind one nti in the 
Aceracez, or maple family. The green flowers of Acer saccha- 
rinum are without petals:. In A. rubrum (red maple) the diœ- 
cious flowers are crimson, and-the visitors are Andrenida and 
Diptera. There is no reason to:suppose that the crimson color- 
ing has been developed by insects, for.the entire flower, the leaf 

