THE PRINCIPLE OF ADHESION. 79 



has suggested the term ejnsepaloics. In the Rose, however, 

 which secretes no honey, the sepals are almost, if not 

 entirely free, and articulate readily ; whereas, in other 

 rosaceous plants, if the receptacular tube does not itself fall 

 off, as in Prunus, the calyx remains persistent. 



Although it is usual to regard perigynous petals and 

 stamens as episepalous as well — that is, "upon the sepals" 

 — when the receptacular tube is well pronounced, it is more 

 strictly in accordance with anatomical structure to i-egard 

 the former as brought into close proximity to the calyx, 

 rather than being really inserted upon it. In many other 

 cases, as in Lythnim and JDapline, the whole of the tube has 

 all the appearance of being truly calycine and not recepta- 

 cular; so that "episepalous" will then best describe their 

 condition of adhesion. 



It is rare to find a gamopetalous corolla adhering to the 

 calyx, but it is so in Cticurbitacece, as in the genera Cucumis 

 and Bnjonia, where the two outer whorls are united. 



Ph. Van Tieghem observes* that the union may be the 

 result of the fusion of the respective parenchymas alone, 

 leaving the cords proper to each organ distinct. I think, 

 however, that it will be found to be more frequently the 

 case that when the cords are superposed, they are fused 

 together below, but separate when the organs become free. 

 This is well seen in Prunus. The sepaline and petaline 

 cords branch, by tangential chorisis, about half-way up the 

 receptacular tube, and thus give rise to ten stamens. Each of 

 the petaline cords branches on either side again, at a different 

 level, by radial fission, and gives rise to ten more.t So that if 

 we retain the term " episepalous " for the stamens, we must 

 understand that, while the actual stamen is practically free 



* Traile Botaniqiie, p. 390. 



t This -will be described more fully below (see Fig. 28, p. 95). 



