318 TRIGONOCARPALES [CH. 



of Conostoma: this is seen above the sclerotesta in the apical 

 region of fig. 494, E, sa. 



Gnetopsis anglica Kidston MS. 



This species (fig. 494, H) is represented by seeds from the 

 Middle Coal Measures near Barnsley, Yorkshire, 4 mm. long with 

 apical appendages at least 2-2 cm. in length and probably four 

 in number. The appendages do not show the hairs which form 

 a prominent feature in the French specimens, but this is probably 

 the result of imperfect preservation: there are indications of 

 hairs on other specimens in Dr Kidston's Collection. The type- 

 specimen, in Dr Kidston's Collection, was generously lent to me 

 for examination. 



Gnetopsis, while agreeing with Conostoma in the more important 

 features, is distinguished by the apical plumes, the very slight 

 development of a tent-pole prolongation of the nucellar apex 

 (fig. 494, E, t), the smaller number of vascular bundles, and by 

 the presence of an enclosing cupule (fig. 506, E). In its slight 

 departure from radial symmetry Gnetopsis forms a transition 

 between the Radiospermeae and the Platyspermeae. It is 

 undoubtedly the seed of a Pteridosperm, but nothing is known 

 as to the nature of the vegetative organs of the parent-plant. 



II. TRIGONOCARPALES. 



In this group are included radially symmetrical seeds for the 

 most part belonging to members of the Medulloseae. The peri- 

 pheral zone of the nucellus is supplied with vascular tissue and the 

 nucellus is free within the integument except at the base; it is 

 superior and not semi-inferior 1 as in recent Cycads and in Lageno- 

 stomales. The ovule of Myrica Gale, in which the nucellus 

 stands free within the single integument, affords an interesting 

 parallel to seeds of this class in contrast to the usual Angio- 

 spermous type with a laterally coalescent nucellus. In Myrica 

 Gale 2 the vascular supply is confined to the integument. There 

 is a comparatively broad pollen-chamber and in some types the 

 lateral tissue of the nucellus is prolonged as a tube within the 

 micropyle. The usually ribbed testa is differentiated into an 



1 Oliver (02) p. 146. 2 Kershaw (09). 



