T.EKIOPHYLLEiE— TiENIOPHYLLUM. 249 



of pliyllotaxy. These cicatrices, several of which are indicated in the 

 figure Last mentioned, are the points of origin of small leaflets, fragments 

 of which are noticed on the large slab. Usually these leaflets are found 

 still attached to the larger leaf. The form of the scars of the small leaves, 

 as well as the irregular sinuosity of the axis within the larger leaves, suggests 

 that the latter, when uncompressed, are cylindrical or rounded, a suggestion 

 that is demonstrated by a number of cross fractures, two of which are 

 obliquely seen in PI. LXXI. It is probable that the main body of the 

 tissue within the relatively thin wall of the leaf is composed of delicate 

 material, such as thin-walled parenchyma cells, perhaps with cavities, 

 environing the central fascicle or axis, so that during- the maceration attend- 

 ing fossilization the interior often became hollow or partially so, thus 

 releasing the unsupported axis, which lies somewhat flexuose between the 

 walls of the collapsed leaf In No. 644 these axial fascicles, which may 

 also be found in the leaflets, are plainly seen, as is also the nervation. 

 Specimen No. 645 shows a rather slender segment of what appears to be a 

 slender branch, 10 cm. long and 8 mm. wide near the base, bearing several 

 leaflets, seemingly without system, and terminating in a tuft of leaves. 



The mutual relation of the leaflets is better indicated in Fig. 4, PI. 

 LXIII. Here we find a segment which seems by its texture, nervation, 

 striation, the presence of "the rather lax fascicle, and its size to represent an 

 isolated leaf or small axis from which pass several leaflets. The latter have 

 the characters of the larger leaflets. At both upper points of division we 

 see the bases of two leaves, apparently oi'iginating at the same or approxi- 

 mate points. This feature, as well as the general aspect of the large 

 segment, may be compared with the figure of Besmiopliyllum gracile given by 

 Lesquereux in the Coal Flora.^ The type of the latter species and genus 

 is now No. 9251 in the Lacoe collection, it ha\dng formerly rested in the 

 Lesquereux collection. As noted by Lesquereux,^ the round points showing- 

 scars of bundles of leaves are seen all along the stem. This fasciculate 

 habit of the leaves in some places, while at other points they were single, 

 seemed anomalous to him. In fact, this character appears to have consti- 

 tuted the essential basis for the separation of this type from Tmiiophyl- 

 Imn, with the leaves of which the leaves of Desmiophyllum were said to 



' PI. Isxxii, fig. 1. Proc. Amer. Phil. Soc, vol. xvii, 1878, pi. liii, fig. 1, p. 333. 

 ''Coal Flora, vol. ii, p. 556. 



