OF THE WOODY ZONE IN CALAMITE. 181 



portions of these appendages must have been slender. 

 At the same time I infer that they were something 

 more than leaves^ from the arrangement of the vessels of 

 these bundles when seen in a transverse section; they 

 exhibit^ as is seen in fig. 17^ the radiating arrangement 

 of a woody twig^ rather than what we should expect in 

 vessels merely destined to supply a leaf. The only wonder 

 is^ that lateral appendages so freely supplied with vascular 

 tissues should ever be deciduous, which those of the Cala- 

 mites seem to have been_, or we should frequently find them 

 in situ J which has not yet been done. The difiiculty is 

 partially surmounted by the supposition that such small 

 branches were jointed, and exceedingly slender, especially 

 at their points of attachment to the stem; and we find 

 such slender-jointed twigs in the Asterophyllites, to which 

 so many observers have referred as probably constituting 

 the branches and foliage of Calamites. With this deci- 

 sion I am strongly disposed to agree. For the above rea- 

 sons I regard the restorations of Dr. Dawson as approach- 

 ing nearer to the truth than those of M. Deslongchamps. 

 But of course I differ from Dr. Dawson when he regards 

 his restorations as representing an Equisetaceous type of 

 plant distinct from Calamodendron. 



During this investigation I have been forcibly impressed 

 with the almost universal occurrence,, within the interiors 

 of other plants, of the cylindrical rootlets of Stigmaria ; 

 they appear to have penetrated every thing that was pene- 

 trable. They have forced their way most abundantly into 

 the interior of the lax piths of Calamodendra, Lepido- 

 dendra, and Dadoxylons, often making the interpretation 

 of sections of these plants difficult to the eye unfamiliar 

 with the aspect of these ubiquitous rootlets. Their pene- 

 trating tendency has culminated in one of Mr. Butter- 

 worth^s specimens, in which one rootlet has forced its way 



