PRESIDENT'S ADDRESS. Ixxi. 



is well illustrated in the living Zamia Skinneri. At the summit of 

 the tree there is a conical bud covered by several bud-scales. The 

 author compares this terminal bud with Encephalartos Altenstinii, 

 both bearing a striking resemblance to each other in this respect. 

 There is no appearance of a lateral inflorescence, and it is probable 

 that the flowers, as in the recent species, were produced at the 

 apex. Mr. Seward names it Cycadeoidea ftigantea. A piece of 

 coniferous wood slightly charged with pyrites is the only repre- 

 sentative of plant-life in the Okeford Fitzpaine bed, but the only 

 elements of it which can be traced are the medullary rays and the 

 aunulations of growth. Perfect certainty in the determination of 

 Coniferae can only be obtained when they are found in conjunction 

 with the cones. Fragments of wood having the structure of 

 living conifers are found throughout the entire series of the 

 geological formations, from the Middle Devonian, and began to 

 be common everywhere as early as the Coal Measures. It is 

 difficult to distinguish the genus of a conifer by the structure of 

 the wood, the annular rings and pits. Goppart, who was the first 

 to take up this branch of research, found that it is only in the 

 rarest cases this can be obtained. He groups most of the Abietineae 

 in the family Pinites ; Araucarias and Dammaras with Araucarites ; 

 Cupressinse and Podocarpse with Cupressinoxylon ; and Taxinea? 

 with Taxites. Krauss, after a careful examination, found that the 

 breadth of the annual rings, the number of the row of pits, and the 

 height of the medullary rays cannot be accepted as distinctive 

 characters. He showed, too, that in the case of a connected stem 

 and branch from a bed of lignite, if the two had been found separate 

 they would have supplied two good species. The Abietinere probably 

 first appeared in the Rheetic beds, and continued to be abundant in 

 the Cretaceous and the Tertiary. Pinea appears for the first time 

 in the Upper Greensand. The annual rings are absent or undefined 

 in the Palaeozoic coniferous woods, but better defined in the Liassic 

 and increasingly so in the Oolitic and the Tertiary conifers. In 

 tropical countries the rings are not so well marked as in the woods 

 of trees whose period of vegetation is interrupted by seasons of 



