60 EQUISETITES. 



respectively recall the slender branches and leaf-sheaths of the 

 English species. 



Numerous examples of Equisetites columnaris are met with in 

 practically all collections of Inferior Oolite plants. The smaller 

 forms, formerly spoken of as Equisetites lateralis, are less common, 

 but good specimens may be seen in the museums of Cambridge, 

 Oxford, Manchester, York, Scarborough, and elsewhere. 



The large stems of the recent species, Equisetum giganteum, L., 1 

 which grows in the marshes of tropical America, may be compared 

 with the still larger plant, which must have formed a prominent 

 feature in the landscape of the low-lying marshy ground bordering 

 the Jurassic sea in the north-west of Europe. 



V. 26130. PI. XIX. Fig. 1. 



This small specimen shows two nodes with the short stumps of 

 two alternating whorls of branches. The knobs or branch-scars 

 occur at regular intervals on each branching node, and the members 

 of each whorl are situated midway between those of the next 

 whorl. 



In this cast the pointed tips of the leaf-segments have not been 

 preserved, but the form of the sheaths is clearly indicated. 



40,681. PL XIX. Fig. 3. [Also in Seward (98), p. 265, 

 fig. 58B.] 



The large cast, of which the figure represents a portion of one 

 node, measures 49 cm. in length, and affords a good example of 

 the large type of branch with long intemodes. The organic 

 substance of the stem has been replaced by a thin film of 

 carbonaceous material encircling the sandstone cast ; the bulk 

 of the specimen being no doubt the cast of a large hollow pith. 

 The breadth of the branch is 5 '5 cm., and the internodes have 

 a length of 13-14 cm. The leaf-sheaths consist of 70-80 teeth, 

 usually truncate at the margin of the sheath, but in the portion 

 represented in Fig. 3 the acuminate distal ends of the teeth are 

 faintly indicated. The leaf -sheath projected slightly from the 

 surface of the branch, the intervening space being filled with 



1 Hooker (61), pi. Ixxiv. 



