228 



DE. AGHES AEBEE ON" THE 



(7) The Sporangium. 



The extreme tangential width of the sporangium is 3 mm. and its radial length is 5 to 

 6 mm. As already pointed out, it appears to have been shallow in its vertical dimension. 

 A pad of sterile tissue occupies the floor of the sporangium, and from this a plate-like 

 process arises into the cavity in the median plane. The sporangium wall consists of 

 the usual columnar outer layer, with a lining of soft tissue. 



(8) The Spores. 



I 



The spores are about 0'023 mm. in diameter. They have a narrow border in the 

 equatorial plane, and in some cases the characteristic triradiate marking is visible 

 (Text-fig. 2, C). 



(9) Comparison with other forms o/* Lepidostrobus oldhamius. Will. 



m 



The dimensions of the whole cone, the axis, the vascular cylinder, and the sporophyll 



* 



traces of Jj. oldhamius f. pilosus agree closely with those of the form which Maslen 

 distinguishes as L. oldhamius. Will. (a). It differs from the latter, however, in several 

 respects. The number of xylem elements in the sporophyll traces is somewhat greater, 

 and the traces cut across in any given transverse section are more numerous. The 

 thick continuous zone of protoxylem, the relatively small amount of metaxylem, and 

 the absence of peripheral barred tracheides are also features in which the form which 

 we have described diverges from Maslen's (a) form. 



When we compare L. oldhamius f. pilosus with the type form of L. oldhamius 

 (Maslen's (/3) form) we find that the cone of the former is more fragile and the sporangia 

 considerably smaller and shallower, while the free overlapping laminae of the sporophylls 

 form a more conspicuous feature. The anatomy also offers a marked contrast, since the 

 metaxylem, instead of being massive as in L. oldhamius^ hardly forms a continuous 

 zone. 



It should be jjointed out, however, that all the characters which distinguish 

 X. oldhamius f. pilosus from the other forms of i. oldhamius^ including even the 

 occurrence of hairs upon the laminae — a unique feature as far as petrified material 

 of Lepidostrobus cones are concerned — may possibly be due to the fact that the sections 

 of this form, which we have described, are all cut near the apical region of the cone. 



5. On a Case of Yariation in the Anatomical Chaeacters of Different Regions 



IN A Single Cone. 



In his memoir on Lepidostrohus , Maslen f drew attention to the need for ** 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." No series of 

 preparations, so far as I am aware, has yet been made with this object definitely in view; 



♦ Maslen, A. J. ('99), p. 361. 



C 



