18 PHYLLOTHECA. 



leaf-sheath seen between the ridges at the node in favourable 

 specimens in which the leaf-sheath is absent. Nodes sometimes 

 slightly tumid, and ridges of the internodes often puckered at the 

 node. Large branch- scars occur occasionally above the node. 

 Pith (?)-casts imperfectly known, apparently more coarsely ribbed 

 than casts of the external surface. Leaf-sheaths usually shorter 

 than the internodes, and generally closely appressed to the axis, 

 sometimes rather lax. Free segments linear, uninerved, 14 to 24 

 or more, often reflexed. Fructification imperfectly known. 



The size of the leaf-sheath varies greatly in different specimens. 

 Those of the main axes, with internodes 2*5 or 3 cm. long, and 

 6-28 mm. across, are 13 mm. in length, and the free segments 

 3'8 cm. long. In the case of branches with internodes of 13 mm. 

 in length, the leaf -sheaths are smaller and less than 7 mm. long, 

 and the free segments average about 6 mm. in length. These small 

 leaf-sheaths commonly occur detached and isolated. (PL II, 

 Figs. 7 and 8.) 



The evidence as to the fructification of Phyllotheca australis is very 

 scanty. The best known cone is that of P. Rallii, a Carboniferous 

 species from Asia Minor, described a few years ago by Professor 

 Zeiller. 1 In this case the strobilus consists of alternating verticils of 

 sterile bracts, and sporangiophores. The latter arise perpendicular 

 to the axis, and bear four ovoid sporangia on the inner side of 

 a peltate, distal expansion. It must be confessed that the general 

 character of this cone is singularly like that of the Calamitean 

 fructification Calamostaehys ; an indication of the close affinity of 

 these two gonera. 



McCoy 2 has figured a specimen from Newcastle, New South 

 Wales, now in the Sedgwick Museum, Cambridge, which may 

 possibly be a fructiferous branch of Phyllotheca australis. A careful 

 re-examination 3 of this specimen has not added anything further 

 to our knowledge, as the preservation is far from good. It consists 

 of an axis, segmented into a number of short internodes, without 

 any definite evidence as to the presence of leaf-sheaths, or of 

 sporangiophores ; but on either side of the axis bunches of small 



1 Zeiller (99), p. 65, pi. v, figs. 2-12. 

 - McCoy (47), p. 155, pi. xi, fig. 1. 

 3 Arber (02 1 ), p. 10. 



