﻿TRUNK STRUCTURE. 



6 9 



illustrated, Nos. 216, 243-246 are cut successively at a distance of from 1 to 3 mm. 

 apart, these numbers thus tracing nearly 1 centimeter of the outer cortical course 

 of the peduncle and leaf traces. Each of these sections is cut obliquely to the 

 stem, so as to strike the bundles at approximately a right angle to their outward 

 and upward course through the cortex. 



216 



243 



245 







Fig. 36.— Cycadeoidea Wielandi Ward. T. 393. S. 216. 243-245. X \. 



Transverse sections through xylem, cortex, and basal portion ol ai.nor, cut at successively lower levels from 1 to 3 mm. 

 apart, beginning with S. 216. Series continued in the next and succeeding figures, which are uniformly lettered. 



la, lb. Peduncular bundle as traced directly from a seed-bearing cone (1 1 ; II, peduncle trace of a second cone : L, axillary leaf trace 

 of peduncle trace I ; L. B., a lateral leaf trace which finally appears to fuse with a branch of peduncle trace I ; 3-6, leaf or 

 peduncle traces near their origin on the woody cylinder ; x, c, and p, xylem, cambium, and phloem of the collateral bundles or 

 wedges forming the woody cylinder of trunk ; m, medulla ; r. ramentum at base of armor. Parenchyma stippled. 



A longitudinal section numbered 249 was next cut through the adjacent 

 flattened peduncular bundle ill) at exactly a right angle to No. 246, and in the 

 position denoted by the line S S in figure 37 (S. 246). This section thus cuts part 

 of the peduncle bundle supply throughout its remaining course, being a nearly true 

 radial longitudinal section. Following section 249, a further series of transverse 

 sections was cut parallel to and beneath S. 246. These sections, therefore, also lie 

 at right angles to and on the right-hand side of 249. Of these, Nos. 247, 250, 



