236 THE STHUCTUKE OF FLOWERS. 



" Branch-buds bearing female flowers have vital power 

 suflBcient to develop into branches. 



"Branch-buds bearing male flowers have not vital power 

 enough to develop into branches, but remain as spurs, which 

 ever after produce male flowers only. 



" Buds producing male flowers only, are more excited by 

 a slight rise of temperature than females, and expand at a 

 low temperature under which the females remain quiescent" 

 [i.e. when the winter temperature begins to give way to the 

 rise in early spring, the males are more easily excited into 

 maturity]. * 



As another authority, I would refer to a paper by Mr. 

 Moore, upon the appearance of male flowers on female trees, 

 such as the Papaw, etc He alludes to Dr. Wight's views, 

 in that he attributes these changes " to the modifying power 

 of the soil and climate acting on the dormant energies of the 

 rudimentary ovaries and developing them into prolific fruit, 

 but at the cost of the male organs." In another case of the 

 Papaw one fertile flower was produced, and that the first 

 which expanded, others being all male " It wonld seem 

 that fertile flowers in these instances have only been de- 

 veloped when the greatest vital energy is present in the 

 plant, which is the case when they first begin to expand. 

 Other instances," Mr. Moore adds, " might be quoted to show 

 that vigour and healthiness increase the female line of vital 

 force in vegetables, whilst weakness is more conducive to 

 the male development." 



This view was corroborated by a case of a young plant 

 of Nepenthes distillatoria, raised from seed. Mr. Moore 

 describes and figures it in the same paper, The lowermost 

 flowers of the raceme bore both stamens and pistil, the 



* On the Relation of Heat to the Sexes of Flowers, Proc Acad. Nat. 

 Sci. of Phil., 1882, p. 1. 



