LIXXEAX SOCIETY OF LOXDOX. 31 



Sigillaria, it appears to afford slender grounds for the adoption 

 of the above view, as regards its uniting such diverse and distinct 

 orders as Cj'cadeje and Lycopodiacece. It is true that it departs 

 signally from the ordinary structure of the latter order ; hut 

 it requires stronger evidence than the more perfect structure 

 and regular arrangement of the bundles of vascular tissue to 

 ally it to Cycadea?, ■with which, in general appearance, habit, 

 fluting, markings, stigmaroid roots, absence of accompanying 

 foliage, and mau)^ other points, it has nothing in common" 

 (p. 421). Thus in the controversy which for so long divided 

 fossil botanists, Hooker at once placed himself on the side which 

 the event has shown to have been the right one. 



Hooker's account of Leindodtndron contains a much needed 

 caution on the question of species. " If the species of that 

 genus," he remarks, " were as prone to vary in the foliage as 

 are those of Lifcopodmin, our available means for distinguishing 

 them are wholly insufficient " (p. 423). He illustrates his point 

 by the Xew Zealand species, Lijcojyodium densum. The suggestion 

 that some of the Trigonocarpi were the seed-vessels (sporangia^l of 

 Lepidodendron is curious, considering that other fossil " seeds " 

 have turned out to be really of that nature. 



At that time Hooker had seen no Calamitese with structure, 

 and he refrains from expressing any opinion as to their relation- 

 ships. It is interesting to find that he looked, though in vain 

 " for evidence of their being Equisetaceae, in the presence of those 

 siliceous stomata with which that order abounds, and which 

 would surely have been preserved in the fossil state" (p. 427). 

 It is only within the last year or two that this evidence has 

 been actually found, in the stomata of Calamitean leaves investi- 

 gated by Mr. Hamshaw Thomas. 



In his concluding remarks, Hooker speaks of the abundance of 

 specimens, suggestive of most interesting points, still to be 

 worked out. He hoped that they would form the materials for 

 a succession of essays in the Memoirs of the Geological Survey, 

 but only two more were ever published, his Himalayan expedition 

 intervening. 



The first of these is his memoir " On some Peculiarities in the 

 Structure of /Stif/maria.^' The merit of this jiaper consists in 

 the excellent and well-illustrated account given of the internal 

 structure of Stigmaria, which was already known to be the root, 

 or at least the underground portion of ^ifiillaria. Only in one 

 point was Hooker seriously mistaken regarding the anatomy. He 

 allowed himself to be misled by an observation of Goeppert's, 

 and believed that the vascular strands passing out through the 

 medullary rays originated from isolated bundles occurring in the 

 pith. As "Williamson showed, nearly 40 years later, no such 

 medullary bundles exist ; Goeppert was deceived by Stigmarian 

 rootlets burrowing in the decayed pith, and took them for integral 

 parts of the structure. 



The comparison drawn between the structure of Stigmaria 



