3 go THE POPULAR SCIENCE MONTHLY. 



most frequently broken, and especially in those flowers having an 

 indefinite number of stamens and petals. In such plants in the 

 wild state there is usually no established uniform number for 

 eit her of these parts, and it may be that they vary as circum- 

 stances determine. In such cases it seems more natural to sup- 

 pose that one gives place to the other, than that there is an inde- 

 pendent development of a new part. However, when we come 

 to the cultivated plants, this seeming chasm between petals and 

 stamens is bridged, and the difficulty now turns upon deciding 

 whether a certain organ is more or less stamen than petal. 



As seen from both a physiological and morphological point of 

 view, the pistil is considered the most highly differentiated part 

 of the flower, the stamen next, petal next, and sepal least. Under 

 the conditions obtaining with the cultivated rose, stamens are less 

 important than petals, and probably less easily produced. Instead 

 of the slender filament surmounted by the two lobes of the anther, 

 bearing thousands of expensive pollen-grains, there is a broad, 

 loose-celled, showy petal. When a stamen is replaced by a petal, 

 it is naturally termed retrograde metamorphosis. In the rose, as 

 in many other cultivated plants, all gradations may be found, 

 from a normal stamen, with a slight color-line along one side of 

 the slender filament, to the perfect petal, which may have a small 

 notch at the tip, marking where the anther might have been. So 

 long as the demand for self -propagation is met in other ways, the 

 tendency to produce seed may be overcome, and the plant spends 

 its energies in the formation of showy blossoms, possibly losing, 

 for the time at least, the power to ripen seed. If the selective 

 power of the rosarian is now withdrawn, while at the same time 

 the stimulation of high culture remains, the inference is not un- 

 warranted that the retrogression would continue so far that no 

 flowers develop. It may be that the so-called green roses some- 

 times met with furnish solid ground for such a view. At any 

 rate, they are forcible examples of the throwing off of floral dis- 

 guises, and the true nature of the parts becomes evident to the 

 most skeptical. 



Rosaceous flowers furnish examples of the simplest form of 

 doubling. In many others the struggle between the two forces 

 seems to have been more violent, and the results are far from uni- 

 form, even in the same flower. In some species the broadening of 

 the stamen takes place above the anther, as if the filament had 

 become prolonged and petaloid. Frequently with such structures 

 the rudimentary anther is at the base of the petal, or one half is 

 midway upon one side, and the other opposite it, the connective 

 having broadened out into the body of the petal. It is not un- 

 usual to find one half of the organ petaloid, while the other is 

 contracted, contorted, and bears an anther-lobe containing fully 



