296 



THE STRUCTURE OF FLOWERS. 



BcecMa diosmcefoUa ; * but as tliey 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 the summit of the hollow recepta- 

 cular tube, the car^Dels 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 

 JRanunculus auricomus (Fig. 78, h). Pistils of other flowers 



Fig. 78. — StameniferoTis carpels of 'Willow 

 (a) and Ranunculus auricomus (b). 



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, Frunus,-f etc. 



Pollen within ovules has been met with occasionally, as 

 in Passijlora and Uosa arvensis.X 



In some members of the Cruciferoe, as Cardamirie 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 inside of the hip of a rose. 



t See Weber, Verhandlung des Nat. Hist. Vereines der Preuss Rhein. 

 und Westph., 1860, p. 381. 



X Teratology, p. 185. 



