CONIFERALES 297 



nitely organized as cones, except in the taxads and some of the podo- 

 carps, where it is possible that a cone is present, but so reduced or 

 modified that botanists fail to recognize it. 



There is a single integument. Only by interpreting the epimatium, 

 the aril, or the ovuliferous scale as an integument, can there be two 

 integuments. We should interpret the epimatium as an ovuliferous 

 scale. The nucellus is free from the ovule, at least in early stages of 

 development. Where the two structures are not free from each other, 

 there is said to be a union or fusion. Probably there is not a single 

 case of fusion in the order, but, rather, the same phenomenon appears 



Fig. 301. — Araucaria bidwilli: the ovuliferous structures: h, bract; /, the "ligule"; 

 0, young ovule in the spore-mother<ell stage; /, integument; X7. 



which gives rise to perigyny and epigyny in angiosperms. A growth 

 below the free portions carries them up, and, throughout this region 

 of common growth, the nucellus and integument are said to be 

 united. In this sense, there is considerable union in the Abietaceae, 

 where nucellus, above the level of the megaspore, is free from the in- 

 tegument. In the Taxodiaceae there is some union at the base. In 

 the Cupressaceae the two are free, or are more or less united at the 

 base. In the Araucariaceae the nucellus and integument are very 

 free, in Agathis australis the ovule even being stipitate. In Taxus the 

 nucellus and integument are free, even in later stages; but in Torreya, 

 chalazal growth is so extensive that, in later stages, only a small part 

 of the nucellus is free. 



Ovules are orthotropous, as in Taxus; or anatropous, as in Podo- 

 carpus; or may have intermediate positions. Approximately half of 



