100 EXPLANATION OF PLATE 62. 



most beautifully preserved, and the integuments of 

 the petiole b, longitudinal vessels e, and gum vessels 

 j\ correspond with those in Fig. 1. See V. I. p. 375, 

 Note. (Original.)* 

 Fig. 3. Transverse section of a portion of the lowest 

 Petioles, in PI. 61. Fig. 3, b, c, magnified four times. 

 The disposition of the bundles of vessels is nearly 

 parallel to the integument of the Petiole.f 

 d, Magnified portion of the double woody circle, within 



the Embryo bud, PI. 61. Fig. 3. 'd. 

 d'. More highly magnified portion of the embryo double 



woody circle d. 

 c\ More highly magnified section of one of the bundles 



of vessels, adjacent to c. 

 These bundles of vessels, exhibit, in their transverse Sec- 

 tion, a series of minute tubes, arranged in rows, and be- 

 tween these rows, opaque plates of compressed cellular 

 tissue, resembling portions of medullary rays. 



The fibrous structure of the integument is preserved in 

 several parts of b. See V. I. p. 376, Note. (Original.) 



* Mr. Robert Brown has noticed in the cellular tissue of a silicified 

 trunk of Cycadites, portions of Calcedony bearing the form of extrava- 

 sated gum within the trunks of recent Cycadese. He has also recog- 

 nised spiral vessels, in the laminated woody circle of a mature trunk 

 of fossil Cycadites, and also in the laminated circle within a silicified 

 bud of the same, near its origin. 



t A familiar example of a nearly similar disposition of bundles of 

 vessels, passing into the Petiole or leaf-stalk, may be seen in the base 

 of the fresh fallen leaves from a horse-cbestnut tree, or in the scars on 

 a cabbage-stalk, from which leaves have fallen off. 



