STRUCTURE OF LEPIDOSTROBUS. 371 



where the preservation is sufficiently good for such points to be determined, and must, in 

 my opinion, be regarded as an essential character of the genus " *. 



The ligule has been described and figured in a former contribution to the ' Annals of 

 Botany,' and but little need be said about it here. Its position, quite close to the distal 

 extremity of the line of attachment with the sporangium, and its distance (about 

 1'5 centim.) from the periphery of the axis of tbe cone, are of course consequent 

 on the great elongation of the sporangium in the radial direction so characteristic 

 of Lepidostrobws. Thus the whole of the horizontal (sporangium-bearing) portion of 

 the sporophyll appears to be the homologue of the short leaf-base or cushion of the 

 vegetfitive stem. 



Passing to tlie free portion of the sporophyll, Williamson's figures already quoted show 

 that at the periphery of the cone it expands in all directions, forming a somewhat peltate 

 extremity. The downwardly-directed lobe is thick, and covers and protects the sporangia 

 below. The upw^ardly-directed scale is represented in Williamson's and Binney's figures 

 as being comparatively short. PL XXXVIII. fig. 34 shows, however, that each sporophyll 

 extends for a considerable distance upward, and that the sporangia are therefore 

 protected in a very complete manner. 



The peltate extremity of the sporophyll is of course traversed by the leaf-trace bundle, 

 associated w ith which are many short tracheides (" barred cells ") forming a kind of 

 transfusion-tissue, probably compensating somewhat, physiologically, for their uninervate 

 character. Some of these short tracheides, which occur also in the vegetative leaves, are 

 shown on PI. XXXVIll. fig. 35. 



Lepidostrobus OLDHAMIUS (y). 



PI. XXXVII. fig. 21 is a photograph of the transverse section of a cone wiiich, although 

 clearly of the same general type as the forms already described, yet differs in certiiin 

 details of its structure. W^hether these differences are sufficient to constitute it a distinct 

 species or not seems impossible to determine until more material is at hand. What is 

 particularly needed is complete cones which can be cut up throughout their entire 

 length so as to show what variations in structure, if any, take place in different regions 

 in the same cone. 



However, whether this be a distinct species of Lepidostrobus or only a variation 

 dependent on the part of the cone from which the section was cut, or other reasons, it 

 seems advisable, provisionally, to give it some special designation, and I therefore 

 propose to call it the y form of Lepidostrobm oldhamius. 



The Williamson Collection contains several slides (C.N. 571, 578, &c.) referable to 

 this form, as does also the collection of palseo-botanical sections recently transferred 

 from the Botanical to the Geological Department of the Natural History Museum. 

 l)r. Scott has also kindly allowed me to examine several slides in his collection (S. 75, 

 76, 77, 610, 615), from one of which (S. 610) the photograph, copied in PI. XXXVII. 

 tig. 21 , was taken. 



• Phil. Trans. B. 1898, p. 99. 



