PIN US S YL VESTRIS. 1 63 



by an ovary ; whence the entire group of plants having 

 this character are called gymnosperms. Latterly, there 

 has been much controversy as to the nature of the 

 carpellary scale and whether the ovule is really or 

 only apparently naked. The latter question involves 

 the determination of the nature of the integument 

 of the ovule. It is held on the one hand that the 

 ovule consists of nothing but a nucellus, and that 

 the coat surrounding this nucellus is the homologue 

 of the wall of the ovary. On the other hand it is 

 contended that this structure is the true integu- 

 ment of the ovule and that the scale which bears 

 the ovule is an open carpel or pair of carpels. 17 In 

 the laboratory directions we have adopted the latter 

 view, calling the organ which bears the ovules a carpel- 

 lary scale. This carpellary scale is theoretically " com- 

 posed of two leaves of an arrested and transformed 

 branch from the axil of the bract, which are in the 

 normal manner transverse to the subtending bract, 

 : * * each bearing an ovule on its dorsal [as to 

 position, upper] face; the two are coalescent into one 

 by the union of their posterior edges, and the scale 

 thus formed is thus developed with dorsal face pre- 

 sented to the axis of the cone, the ventral to the bract. 

 It is therefore a compound open carpel composed of 

 two carpophylls. This character of being fructiferous 

 on the back or lower side of the leaf occurs in no other 

 phaenogamous plants." 18 



11 References to extensive literature of this discussion may be found in 

 Gray, Struct. Bot., p. 272. For a general statement of views and 

 summing up of argument see Eichler, Sind die Coniferen gymnosperm 

 odernicht? Flora, 1873, p. 241. Consult also Sachs, Text-book, 2nd 

 Eng. ed., footnote, p. 507. From references in these places the whole 

 subject may be traced. 



18 Gray, Struct. Bot., p. 273, footnote. 



