156 HISTORY OF BOTANY 



metamorphosis was retrogressive. The school that took 

 Engler for its leader regarded the primitive flower as 

 composed of one or more naked sporophylla, flowers of 

 higher type arising from them by differentiation of these 

 sporophylla into stamens and carpels and by the addition 

 of a perianth. The school that followed Bower, on the 

 other hand, regarded the primitive flower as a strobilus 

 provided with a perianth which had arisen by sterilisation 

 of the outer or lower sporophylla. 



The morphological nature of the female cone of such 

 a plant as Pinus was another of the debated questions of 

 the last fifty years of the nineteenth century, and the 

 matter was again given prominence to by Lotsy in his 

 monumental Stammesgeschichte, which is still in course of 

 publication. I do not think, however, that there is 

 much to be gained by detailing all the, often fanciful, 

 interpretations that were put forward. Perhaps the 

 explanation advanced by Sachs and Eichler was the one 

 most generally accepted, viz. that the cone is a single 

 flower consisting of an axis with many sporophylla 

 arising from it, each sporophyll being a carpel bearing 

 on its upper surface a large placental scale on which are 

 developed two ovules. It is well, however, that you 

 should bear in mind that Lotsy does not accept an 

 explanation so simple as this. In the volume of his 

 great work entitled Cormophyta Siphonogamia, 1911, he 

 says : " Closer examination shews that the female fructifi- 

 cations met with in this group (Coniferae) belong to two 

 distinct morphological types. ... In Cupressus we have 

 a cone whose axis bears one type of bract or scale only. 

 This scale bears on its upper surface the ovules or mega- 

 sporangia, and hence is the equivalent of a sporophyll, 

 and the cone is consequently a strobilus or flower. The 

 conditions are quite different in a cone of Abies. Instead 

 of carrying only one kind of scale, the cone axis shews 

 two types of scale, viz. sterile, pointed, narrow scales, 

 the bract scales, and fertile, broad, obtuse scales, the 



