6 PROF. MARGARET J. BENSON ON 



III. Details of Structure. 

 1. The Outer Integument or Cupule. 



The cupule is probably a youth organ which did not accompany the ovule when it 

 separated from the parent plant. In some sections it is represented by fragments, but 

 seems to owe this preservation to the fact that parts had adhered to the slimy surface 

 of the inner integument. The tissue is far more uniform than that of the inner integu- 

 ment, and the vascular bundles more rounded in transverse section. 



The preservation does not admit of a decision as to the relative position of the 

 phloem and xylem in each strand, nor have I been able to ascertain the number of 

 the latter, but the distribution of those which can be made out is such as to suggest 

 there are eight, which is also the number of the strands in the inner integument 

 (text-fig. 2, c, v.b.). 



It is possible that, at the apex, the cupule was lobed like that of Lagenostoma 

 Lomaxii* but most of the transverse sections passing through it show it as a continuous 

 sheath (PI. I. fig. 5). 



In the specimen shown in fig. 2 of the same plate, there are at the base of the 

 cupule a few longitudinally disposed fibres of cylindrical form, which are similar in 

 character and position to those in the neighbouring petioles of Heterangium Grievii. 

 With the exception of these and the tracheides of the vascular strands, the only tissue 

 elements preserved in the cupule are parenchymatous. 



2. The Inner Integument. 



The inner integument is only free from the nucellus in the upper part, where it 

 corresponds in many respects with the so-called canopy of Lagenostoma. In the 

 basal three-fourths of the ovule there is no distinct layer of demarcation between 

 the nucellus and the peripheral vascular part commonly regarded as the part of the 

 integument adherent to the nucellus. The whole of the ovule, irrespective of the 

 cupule, is surrounded by a remarkably well-differentiated epidermis, which eventually 

 becomes secretory for the most part. On the exposed surface of the inner integument, 

 from the pedicel up to the margin of the micropyle, the epidermal cells are longitudin- 

 ally disposed, brick-shaped bodies. Each cell bears peripherally a small papilla, which 

 later increases in size and eventually ruptures near the apex — a hemispherical cap being 

 pushed aside by the emerging mucilage as in Lagenostoma Lomaxiif (text-fig. 3, 

 a, b, and c). 



Near the micropyle the epidermal cells change their character. Outside, they 

 form the structure to which I have referred as the "frill." It is seen in PI. I. fio-. ]. 

 There are several sections which demonstrate that the "frill" is not continuous. In 



* Olivbb and Scott, " On the Structure of the Palneozoic seed Lagenostoma Lomaxii," Trans. Roy. Soc. 

 (Lmd.), 1904 (]>. 217). 



, t (>uvi:ii and Scott, loc. cit., pi. x. fig. 28 B. 



