222 



DE. AGXES AEBER ON THE 



life; the space occurs throughout the pedicel and occupies part of the heel of the 



lamina (PI. 26. fig. 43). 



When the pedicel leaves the axis, the xylem portion of its trace consists of 16 or more 

 elements. There seems to be a tendency for the smaller elements (? protoxylem) to he 

 placed internally towards the ventral side of the bundle. The general structure of the 

 pedicel is clearly shown in the case of some sporophylls bearing young or abortive 

 sporangia, which are cut tangentially near the apex of the cone (PL 26. fig. 47). In the 

 region of the junction of pedicel and lamina, the bundle is accompanied by a considerable 

 mass of large transfusion tracheides. These lie chiefly on the ventral side, but a few 

 occur on the dorsal side (PL 26. fig. 44) and also on the flanks of the bundle. 



In the upturned part of the lamina the outer tissues are dark in colour and appear 

 to consist of thick-walled cells, but the bundle traverses a clear-looking, parenchymatous, 

 central zone. The bundle is accompanied by transfusion tracheides for some distance 

 up the lamina on the ventral side. The epidermis on the inner face of the lamina 

 forms a particularly well-marked layer. 



(6) The Ligule, 



F 



A ligule and a narrow ligular pit appear to be preserved in the case of one sporophyll 

 (PL 26. filg. 45). 



(7) The Sporangium. 



■ 



The sporangium is attached directly to the upper surface of the pedicel, without the 

 Intervention of a ridge of sterilised sporangial tissue. There is, however, a delicate 

 radial plate of sterile tissue rising into the cavity of the sporangium {st.p., PL 26. 

 fig. 46) . The distal wall of the sporangium slopes sharply backward from the re£:ion of 

 its attachment to the pedicel, thus leaving a considerable space between the upturned 

 limb of the sporophyll and the end of the sporangium (PL 26. fig. 43). The sporan- 

 gium wall consists of an outer layer of columnar dark cells followed internally by one 

 or two layers of thin-walled cells. In PL 26. fig. 48 these two regions of the wall are 

 seen in succession in an obliquely tangential section. 



(8) The Spores. 



The sporangia contain spores whose greatest diameter is 0-028 to 0*03 mm., from which 

 we may infer that the cone was microsporan giate or homosporous. Some of the spores 

 are shown in PL 26. fig. 49. They were bordered in the equatorial plane and the tri- 

 radiate marking is particularly distinct. 



(9) Comparison with other Forms of Lepidostrobus oldhamius, Will, 



It seems clear that the cone under discussion cannot be assigned to the type form of 

 L. oldhamius. It differs therefrom in its relatively small size, in the backward slope of 

 the distal walls of the sporangia (PL 26. fig. 43), which show no tendency to curve over 



