STUDY OF SPIRAEA 455 
es of preparations. Shortly thereafter the peripheral layer 
the hypodermal mass may be distinguished by its lighter 
rand incipient periclinal division, which results in two narrow 
s of cells derived from the archesporial tissue, as shown in 
8, the latter showing this division of the gdeteds wx: layer 
¢ chance of posi- 
keepsthe former : 
