POSITIVE DEDOUBLEMENT. 



97 



found flowers with the usual pair of transversely- 

 placed stamens and a pistil between them. 



Giard describes male flowers of the sedge {Gar ex 

 praecox) becoming hermaphrodite owing to infection by 

 the fungus Ustilago caricis, those of the grass Buchloe 

 dactyloid-es infected with Tilletia buchloeana, and Andro- 

 pogon provincialis with Ustilago andropogonis. 



Leake describes the reappearance of carpels in the 

 male flower of the date-palm [Phoenix dactylijera) 

 (fig. 108). 



Robbins found that the peloric ray-florets of Gail- 

 lardia arista ta, which in their normal zygomorpliic 



Fig. 108. — Phoenix dactylifera (Date-palm). Hermaphrodite flower 

 due to the reappearance of carpels (cp) in the male flower. 

 st, stamens. (After H. M. Leake.) 



condition are neuter, produced both stamens and pistil 

 in perfect development. 



b. Ovules. — The ovules, here regarded as lateral 

 segments or appendages of the carpel, may be increased 

 in number. One or two instances of this may be given. 

 Masters describes a carpel of Ranunculus Ficaria 

 which, in place of the normal single one, bore two 

 ovules, placed not, as usually is the case, on the car- 

 pellary margins, but on the surface of the carpel some 

 little way from the edge. Small mentions an ovary 

 of the groundsel (Senecio vulgaris) containing two 

 laterally-situated ovules. Masters figures a leafy carpel, 

 of the " green rose " bearing two ovules, one on each 



VOL. II. 7 



