SOME FERNS FROM THE CARBONIFEROUS FORMATION. 141 



Fossil Flora, is the small woodcut given by the late Hugh Miller in the 

 Testimony of the Rocks. This example is refigured on PI. IX. fig. 16. Another 

 figure, showing well the form of the pinnae and pinnules of C. bifida, is given 

 by Stur in his Culm Flora, under the name of Toclea Lipoldi. The pinnules are 

 divided into 3-7 very narrow linear segments, in each of which is a simple central 

 vein. The limb of the pinnule is very narrow, forming only a slight border 

 to the nerve. 



On PI. VIII. fig. 1, the specimen has so suffered from decay, that nothing of 

 the pinnules now remains but the veins, the specimen being in fact reduced to 

 the same state of imperfection as that of Lindley and Hutton's original type of 

 the species. This example, however, is specially interesting, as it shows the posi- 

 tion of the fruit on the frond, which is here seen to be situated in the neighbour- 

 hood of the bifurcation of the main axis. From the specimen drawn at fig. 2, it 

 is shown that in the fruiting pinnae the synangia are borne at the extremities 

 of the little branches resulting from a third or fourth series of dichotomies. 



On the surface of the sporangia are generally seen, in well-preserved 

 examples, a few longitudinal fine ridges. At figs. 6a and 3a, two of the 

 synangia are exhibited in profile. At fig. 4, and also in figs. 2 and 3, are 

 represented flattened out groups of sporangia. 



The sporangia individually are slightly fusiform, and united in their basal 

 portion.* 



The affinities of this fern seem to be undoubtedly with the Marattiacew, 

 and in the genus Kaulfussia the sporangia are united to each other round a 

 common point, an arrangement with which the fruit of C. bifida closely 

 corresponds. 



In C. bifida the synangia differ from those of Kaulfussia in the sporangia 

 being free for a considerable portion of their length and in the position of 

 the synangia on the fern. In Kaulfussia the synangia are scattered on the 

 back of the frond. In the more essential structural characters of the fruit, 

 however, the close analogy between the fruit of C. bifida and Kaulfussia is 

 very striking. 



Specimens showing the bifurcation of the rachis are not uncommon, and on 

 the main axis below the bifurcation there are a few barren pinnae, which are 

 usually much smaller and less divided than those above the bifurcation. The 

 pinnae within the fork, formed by the dichotomy of the axis, are at the base of 

 the two arms much shorter than those on the outer side of the fork, but they 

 gradually increase in size as the arms of the fork separate from each other. 

 The fronds never seem to have attained to large dimensions. 



* In one or two sporangia I think there can he detected a small elongated pore a little below the 

 apex, but defer positively affirming its presence till I have more frequently seen its occurrence, and so 

 convince myself that this appearance is not accidental. 



