No. 557] PARTHENOGENESIS IN NICOTIAN A 301 



cock— previously fastened to the rubber tubing— was 

 released and the liquid flowed into the stem as rapidly as 

 it could be used by the plant. The injection was assisted 

 by the weight of its own column, and, in the most cases, 

 by the addition of a short column of mercury, suspended 

 by the surface tension of the liquid. The use of the mer- 

 cury required considerable care, for when the surface 

 tension was overcome by a jar, the mercury sank to the 

 bottom and plugged the capillary tubes. 



The treated species were: N. tabacum var. fruticosa, 

 N. paniculata, N. Langsdorfji var. grandiflora, N. Langs- 

 dorffii, N. alata var. grandiflora, N. attenuata, and N. 

 Sandarce. 



The materials used for the injections are : Sodium phos- 

 phate, butyric and valeric acids, ethyl acetate, acetone, 

 benzol, chloroform, formaldehyde, methyl blue, saffranin 

 and thiazin. The last three are simply stains and were 

 used to trace the course of the liquids. The coloring 

 matter was found to follow the vascular bundles of the 

 stems and the leaves for several inches, and yet the 

 slightest trace was not discovered in the buds. Acetone, 

 butyric, and valeric acids of .5 per cent, strength caused 

 severe injury, formaldyhyde at 2 per cent, caused a 

 slight injury to the foliage, but no other liquid caused a 

 noticeable disturbance. 



All the treated plants, as in the previous experiments, 

 had at least one cluster of buds emasculated and bagged, 

 but all to no purpose, since not even one abortive seed 

 developed. 



Summary 



1. Seed giving plants true to the maternal species in 

 the Fj generation accompanied by aborted seed prob- 

 ably hybrid in nature, was found when certain Nicotiana 

 species were cross-fertilized. Hybrid plants and plants 

 purely maternal were obtained from the same capsules in 

 other crosses. 



2. The capsules of several Nicotiana species were 



