58 



Mr. Gardner on the Origin of the 



culations of the most interesting nature in the mind of the 

 philosopher, and enable him by induction to give a definite 

 and harmonious idea of the former condition of the globe. It 

 was only from the intimate knowledge which the immortal 

 Cuvier possessed of the anatomical structure of the living 

 animals which now people the earth, that he derived the 

 power of giving all but life to a host of its former inhabitants, 

 whose existence and real characters were before totally un- 

 known. If such knowledge is requisite for throwing light on 

 the remains of animals, it must be obvious that the relics 

 which survive of the extinct vegetation of the earth can only 

 be successfully investigated by those who have attentively 

 studied the anatomical structure of that which now covers its 

 surface. To the geologist, knowledge of this kind must be of 

 the utmost value, since we now know that many tribes of 

 plants are as readily distinguished by the structure of their 

 stems, as by the characters which are given to them by their 

 organs of fructification. Thus all the individuals of the na- 

 tural order Coniferae are immediately recognized by there 

 being scarcely any mixture of vascular tissue among the woody 

 fibre of their stems, as well as by their ligneous tissue being 

 marked with circular discs, which are supposed by Kieser and 

 several other vegetable physiologists to be pores, but which, 

 from apparently good reasons, Dr. Lindley considers to be 

 semitransparent granules. Cycadece are recognized by the 

 same want of vascular tissue as in Conifera, and by their 

 wood being marked in the same manner ; but the zones of 

 wood are separated by a layer of cellular substance resem- 

 bling that of the pith, and often as thick as the zones them- 

 selves. The shrubs which constitute the natural order Caly- 

 canthece have square stems, with four woody imperfect axes, 

 surrounding the usual central one ; and the investigations of 

 those who are now devoting themselves to such inquiries may 

 probably lead to the discovery of distinguishing characters in 

 the stems of other well-marked tribes of the vegetable king- 

 dom. 



These remarks have been occasioned from reading the ac- 

 count of the anatomical structure of endogenous plants given 

 by Dr. Lindley in his c Introduction to Botany/ After stating 

 the general plan on which the stems of these plants are formed, 

 the following paragraph occurs at page 82 of the second edi- 

 tion of that work : " The investigations of Mohl appear to 

 show that this view of the structure of endogens requires some 

 modification. According to this observer, every one of the 

 woody bundles of a palm-stem originates in the leaves, and is 

 at first directed towards the centre ; arrived there, it follows 



