THE RECEPTACULAR TUBE. 91 



and U'nihelh'fera', while Ona graced' furnish illustrations of 

 an extension of thereceptacular tube to considerable distances 

 beyond the summit of the ovary, as in Circcea, and probably 

 FucJiaia and OEfwthera are similar cases, A like prolongation 

 is seen in some Compositce with " stipitate " pappus, as the 

 Dandelion, Tragopogon, Eypochccris, etc. 



In tracing the development of the inferior ovary of the 

 GompositcE, the cavity of the ovary appears to be sunk below 

 the level of the first emergence of the corolla and stamens ; 

 and it is this which has suggested the view that the ovary 

 is part of the axis, and that only the style and upper portion 

 of the ovary which is exposed is foliar. 



On the other hand, since there are abundant cases of 

 transitional conditions ; as, for example, between species of 

 Saxifrage, — ;S^. unihrosa having an entirely superior ovary ; 

 S. granulata, one that is half-superior, and 8. tridactylites, 

 a completely inferior ovary ; and moreover, if we compare 

 the Pomece with the other tribes of Bosacece, comparative 

 morphology does not tend to favour the above view held by 

 Sachs, but rather inclines one to the impression that the basal 

 part of the ovary must be carpellary and not axial, though 

 there may be no visible line of demarcation between the 

 cauline and foliar structures.* 



The existence of the above-mentioned facts, and many 

 cases of reversion to entire freedom by "solution," supply 

 good reasons for believing that the development of the 

 carpels is more or less arrested below, wherever they are in 

 contact with the receptacular tube ; yet they retain their 

 power of developing at least one ovule, as is often the case in 



* To regard the septa of an inferior ovary " as the prolongations of 

 the margins of the carpels downwards on the inside of the ovary " 

 (Sachs' Text-Booh, p. 567), seems to be a very strained interpretation iu 

 order to fit the axial theory. 



