No. 557] PABTHENO GENESIS IN NICOTIAN A 291 



celluloid covers, the latter covering was soon discarded. 

 The advantages of the paper bags are, first, they cover 

 a great many buds and, second, they are put on and re- 

 moved very easily. 



Clusters of buds that had been emasculated as well as 

 those that had been decapitated were also ringed a few 

 inches below the buds. The operation was performed 

 with the hope that the food stored above the injury would 

 upset the natural equilibrium of nutrition in such a way 

 as to cause the development of the ovules. In these ring- 

 ing experiments only negative results were obtained, al- 

 though Ewert found that injuries to gooseberry branches 

 favored the development of parthenocarpic fruits. 



Neither the tickling of N. tabacum buds, varying in 

 size from small to large, with a camel's hair brush every 

 half hour for five consecutive hours, nor the cutting of 

 the bases of N. suaveolens and N. commutata buds, with 

 the point of a scalpel, gave results. Professor East has, 

 however, produced a slight swelling in the capsules, but 

 no seeds, by occasionally tickling the buds of the follow- 

 ing species with a sharp-pointed instrument— N. tabacum 

 (vars. fasciated, Sumatra, broadleaf, and Havana), 

 A 7 , alata, N. Bigelovii, N. Forgetiana, N. glutinosa, 

 A 7 . Langsdorffii, N. Langsdorffii var. grandifora, N. long- 

 iflora, N. paniculata, N. plumb agini folia, N. quad rival- 

 vis, N. rustica (vars. hum Ms, brazilica, and teocana). 



Stimulation was also attempted, as already noted, by 

 burning or rather singeing buds varying in development 

 from very young to nearly mature, with a heated plati- 

 num wire. The hot wire was applied to various portions 

 of the buds, namely, to the base, to the top of the ovary, 

 the stigma, and to both the stigma and the ovary. When 

 the pistils were not injured, the blossoms were covered 

 with bags, but covering was not considered essential 

 when the pistils were made functionless. A 7 . Langsdorffi 

 var. grandiflora and A 7 , plumb a gini folia gave no results, 

 but one capsule of A 7 , tabacum produced fifty-six appa- 

 rently normal seeds— none of which germinated after a 



