xxxvn] WILLIAMSONIA 455 



a thick epidermis, and on the sides of the scale many of the surface- 

 cells are strongly papillose (figs. 563, 564). The rest of the inter- 

 seminal scale consists mainly of elongated cells, which in the lower 

 portion of the axis of the scale assume a tubular form, presumably 

 immature conducting elements : in one scale only was any tracheal 

 tissue found and that was represented by 2 3 scalariform 

 tracheids. The scales appear to arise from the axis like the bracts 

 as superficial outgrowths, and probably in a later stage of develop- 

 ment the centre of each scale would be occupied by a vascular 

 strand. The megasporophylls bear a close resemblance to the 

 scales, but in transverse section they appear as smaller and circular 

 organs each the centre of a group of polygonal interseminal 

 scales precisely as in other Bennettitean flowers (fig. 564; cf. 

 fig. 515). The proximal part of a megasporophyll consists of a 

 column of parenchyma (fig. 563, A, ) extending through half of 

 the length; from this column is detached a narrow cylinder of 

 small crushed cells which most likely represents the remains of 

 tissue that originally occupied the space surrounding the axial 

 column. At a higher level the axial column becomes broader and 

 its short cells more elongated and slightly divergent towards the 

 sloping sides of the conical nucellus. The loose cylinder of tissue 

 is attached to the nucellar cone and prolonged beyond its apex 

 as a broad integument enclosing a very small micropyle (fig. 563, C). 

 The apex of the integument has the form of a shallow funnel: 

 its epidermal cells are papillose (fig. 563, B, C) and the presence 

 of short transversely elongated cells is a characteristic feature of 

 the tissue lining the micropylar canal. The bracts agree generally 

 with those of Cycadeoidea Gibsoniana, Cycadeoidea Morierei, and 

 the American species. The ground tissue is composed of scleren- 

 chyma comparable with the scalariform elements in the bracts 

 of Cycadeoidea Gibsoniana (cf. fig. 520). It is in the possession 

 of long hairs like those on the leaves of Dioon and other recent 

 Cycads that Williamsonia scotica differs from previously described 

 flowers in all of which the fern-like ramental scales are a conspicuous 

 feature. It is interesting to find that similar hairs are substituted 

 for scales in some Indian stems described by Miss Bancroft 1 . 

 Lignier 2 mentions the occurrence of long unicellular hairs on 

 1 Bancroft (13). 2 Lignier (01). 



