STUDY OF SPIRAEA 453 
of more than two carpels in the latter species. Once the 
f the carpel is established, a rather uniform enlargement 
parts gives the necessary room for the many ovules. At 
we indicated in fig. g the last cycle of floral parts, that of 
corolla, has appeared, the petals alternating with the sepals, 
ing just within their edges. 
Sperene Japonica. a 
G. 7.—T: ransverse section of flower at the base of = o - 
the carpellary layer. X 54- : : 
Fic. 8.—Section of same Sones at point ae maximum 
develmmennt of placenta; aa, bb, of 
ridges enlarged, thickened, and curved 
Fic. 9.—Transverse section im 
plane of insertion of stamens and | 
