SPHENOPH YLLEA E. 345 



in which the leaves are of like form, but of somewhat greater length, 

 though we must not omit to say that fructifications occur at the same spot 

 which very probably belong to the stems in question, and which, though 

 imperfectly preserved, yet show some resemblance to those known to have 

 belonged to Sphenophyllum. This is why the plant is considered in this 

 place. If it really belongs to our group, we shall be able to follow the type 

 of Sphenophylleae much farther back than the limits usually assigned to 

 it. An equally strong splitting of the repeatedly forked leaf-blade is 

 figured by Zeiller l in the plant which he has named Sphenophyllum 

 saxifragaefolium. 



As abnormal form, whose connection with the group appears not to be 

 entirely free from doubt, may be mentioned first, Sphenophyllum Thonii 2 , 

 hitherto found only in the highest beds of the Carboniferous formation 

 at Ilmenau and in France. According to Zeiller 3 this plant is distinguished 

 essentially from other species of the genus only by the size of its parts, and 

 by the strength and prominence of the nervation of its leaves, in which the 

 anterior margin is slit up into narrow fringe-like teeth. More decided 

 differences appear in the doubtful remains described as Trizygia speciosa 4 , 

 which, as belonging to the Damuda group of the Lower Gondwana system 

 of India, comes from a higher level than that of the Carboniferous formation, 

 perhaps from the Trias. O. Feistmantel 5 has given a description and 

 figures of this plant, and has also collected the literature. I have seen 

 specimens only in the Botanical Department of the British Museum. The 

 thin filiform stems which are swollen at the nodes bear six-leaved whorls, 

 which appear to be regularly superposed. The roundish wedge-shaped 

 leaves in each node are arranged in three pairs, two of which are exactly 

 opposite to one another, while the third, formed of much shorter members, 

 occupies the interval between them on one side. The arrangement of the 

 leaves is thus unilateral, and there is in all the whorls a broad interval 

 opposite the smaller pair of leaves. Branching has, as far as I know, 

 not yet been observed on the plant. The genus Sphenoglossum found 

 in the blue shales of the apparently Triassic coal-field of Deep River in 

 North Carolina, and described by Emmons 6 , is less known, and as the 

 verticillate broadly wedge-shaped leaves are in fours it can scarcely belong 

 to our group. 



Here again it is to Renault 7 more than to anyone else, and next to 

 him to Williamson 8 , that we owe our knowledge of the inner structure of 

 the Sphenophyllae. This structure has proved to be highly remarkable, 

 and not directly comparable with that of any other plants. A primary 



. ' Zeiller (3), t. 161, ff. 3, 4, 6. 2 Mahr (1), t. 8. 3 Zeiller (3), p. 34, t. 161, f. 9. 



1 Royle (1), t. 2, ff. 1-7. 5 Pal. Ind. ser. xn, Pt. II, p. 69, tt. n, 12. e Emmons (1). 



7 Renault (2), vol. ii, p. 91, and vol. iv, Introd., also (16) and (20). 8 Williamson (1), v and ix. 



