300 



GYMNOSPERMS 



he regards as a second integument. In PJicrosphacra^^' (fig. 303 B) 

 Lawson says the single erect ovule is borne on the sporophyll, close 

 to the axis of the cone. There does not seem to be any structure 



which could be called an ovu- 

 lif erous scale. In Saxagolhca^'^ 

 (fig. 303 D), the ovulif erous 

 scale is comparatively small, 

 and the nucellus protrudes 

 from the micropyle and is 

 more or less glandular, like 

 a stigma. In Microcachrys,^^" 

 also, the ovuliferous scale, in 

 early stages, is rather small 

 (fig. 303 C). 



Dacrydium elaticm, a Suma- 

 tran species recently described 

 by Hagerup, seems to bear 

 the ovule on the adaxial face 

 of a sporophyll, which is the 

 homologue of the male sporo- 

 phyll (fig. 305). Hagerup"* 

 claims that both microspo- 

 rangia and megasporangia are 

 borne on the upper (adaxial) 

 face of sporophylls, just as 

 sporangia are borne in lyco- 

 pods. The "cone" consists of 

 only two sporophylls, and, be- 

 tween them, the sterile tip of 

 the branch which sometimes 

 proliferates. The fact that 

 Hagerup describes and figures an "epimatium" may mean that 

 there is something representing the ovuliferous scale. A detailed 

 study of the development would be interesting. 



When ovules are terminal on the axis, as in Taxus, there is no 

 sporophyll or ovuliferous scale to confuse the interpretation (fig. 

 304 A,B). However, in this case, there is an aril, which many regard 



Fig. 304. — Ovules of conifers: A and B, 

 Taxus baccata — A, at time of pollination and 

 B, somewhat later: i, integument; n, nucellus; 

 a, aril; XiS- C, Crypiomeria japonica: b, 

 bract; 0, ovuliferous scale; i, integument; n, 

 nucellus; X22. D, Thuja occidentalis: i, in- 

 tegument; n, nucellus; X3S. — All after 

 Hagerup."* 



