﻿FOLIAGE. 



IO3 



in the ferns. From these explanations the need of serial sections through a larger 

 number of terminal buds very clearly appears ; although the varied stages of foliar 

 growth already described shed much light on the appearance in life and the general 

 habits of foliar growth exhibited by the Cycadeoidece. The extent to which pro- 

 liferation is found may first be commented on. 



In Cycas there are often produced in the axils of old leaf bases of old trunks 

 numerous lateral buds made up of scale leaves, which may or may not later produce 

 foliage leaves ; and very similar buds, as apparently made up of ramentum-covered 

 scale leaves and destined to form branches, appear in the Cycadeoidese. But the 



Fig. 53. Zamia Vroomi. X \'b. Sub-spherical to slightly columnar type o( cycadean trunk of the 

 same form as various Cycadeoidean specimens from the Black Hills; but markedly differing in the presence of 

 numerous scale leaves which in direct contrast to the Macrozamias with few or no scale leaves appear to 

 exceed the foliage leaves in number. The terminal bud may especially be noted as exactly of the general 

 form seen in the large silicified branch from Minnekahta shown on Plate V, photograph I ; although in the 

 present plant scale leaves, and in the fossil trunk ramentum borne by young leaf axes, or occasional (?) scale 

 leaves, makes up the main bulk of the armor. 



point on which stress is to be laid is that so long as the scale-leaf buds of Cycas 

 consist of imbricating scale leaves only, as the)' often do, they are exactly analogous 

 in position, fonn, arrangement of parts, structure, and appearance to the young 

 fruiting branch in the Cycadeoidese. Almost the only difference is in the less pro- 



