296 



THE STRUCTURE OF FLOWERS. 



Bceckia diosmcefoUa ; * but as tliej grew on the interior of 

 the wall and not on an axile placenta, as is the normal con- 

 dition in the Myrtacece, I expect that it was due to the 

 staminal vascular cords branching off and coming out of the 

 tissue within instead of at tlie summit of the hollow recepta- 

 cular tube, the carpels being more or less arrested. A not 

 uncommon instance is to find the pistils of Willows with 

 open ovaries and bearing one or more anthers on the margins 

 (Fig. 78, a). I have met with a similar occurrence in 

 Banunculus auricomus (Fig. 78, b). Pistils of other flowers 



Fig. TS.— Stameniferous carpels of 'Willow 

 (a) and Banunculus auricomus (Jb). 



Fig. 79.— a, Petaliferous placentas of Car- 

 damine pratensis; b, of Rhododendron. 



have been known to bear anthers in a similar way, as 

 Chamoerops humilis, Prunus,f etc. 



Pollen within ovules has been met with occasionally, as 

 in Passiflora and Bosa arvensis-X 



In some members of the Cruciferce, as Cardami7ie pratensis 

 (Fig. 79, a), round pods are formed instead of the usually 



* Teratology, p. 184. Possibly the ovary was entirely absent, and the 

 stamens would then be growing on the interior of a closed receptacular 

 tube, just as carpels grow upon the i aside of the hip of a rose. 



t See Weber, Verhandlung des Nat. Hist. Vereines der Preuss Bheiu' 

 und Westph., 1860, p. 381. 



X Teratology f p. 185. 



