1915] Goodspeed: Parthenogenesis, Partlienocarpy, Phenospermy 263 



nection Avith the efforts of Wellington to stimulate the production of 

 parthenogenesis and parthenocarpy. These two references will be 

 mentioned below in greater detail. 



Viable seed supposedly parthenogenetically produced has been 

 obtained by Professor East in the case of the following crosses: 

 N. panicidata X N- alata var. grandiflora, N. rustica X N. Tahacum, 

 N. Tahacum X ^- Bigelovii, N. panicidata X ^- Langsdorfii, N. pan- 

 icidata X ^ ■ longiflora, N. panicidata X N. Forgetiana, N. Bigelovii X 

 N. sylvestris, and N. Tahacum var. lanciflora X ^- alata var. grandi- 

 flora (Wellington, 1913, and East, 1910). The supposition that these 

 cross-pollinations induced, by the "extraordinary irritation of foreign 

 pollen" (East, loc. cit.), the production of apogamic or partheno- 

 genetic seed was suggested by the fact that certain of the seeds pro- 

 duced plants "like the mother species and also true hybrids" and 

 that certain of them gave plants "like the mother species and no 

 true hybrids" and that certain others of them gave "no true hybrids 

 on one occasion but did produce true hybrids on other occasions" 

 (Wellington loc. cit.). Species crosses made by Gartner also gave 

 seed in a few eases that produced the mother species and also true 

 hybrids (Burbridge, 1877). This phenomenon has apparently occurred 

 a sufficiently large number of times to preclude the possibility that 

 errors in technique were the cause. Wellington in his experiments 

 produced ' ' abortive seed probably without embryos ' ' by singeing young 

 buds, by exposing young plants to chloroform gas, "cutting away a 

 portion of the pistil and pollinating the stub both with and without 

 the accompaniment of a germinative fluid" and by "shortening the 

 pistils (?) of a flower and grafting the stigma end of another pistil 

 on to the stub and pollinating the same." In only one doubtful case 

 was seed produced "by the simple methods of emasculation and 

 decapitation of blossoms." 



As a result of the very numerous castration experiments of Howard 

 (loc. cit. 1910) on a plant of N. Tahacum — Type 9 (cf. Howard and 

 Howard, 1910) — one castrated flower produced a capsule "the seed of 

 which germinated and produced plants similar to type 9." "In 1911, 

 again, on a plant of type 9, one capsule containing seed was found in 

 about 100 castrated flowers." Three other capsules in every way 

 normally matured and apparently containing seed were produced, in 

 Howard 's experiments, as a result of castrating flowers of another type 

 of N. Tahacum. These capsules were, however, lost before any definite 

 determinations were made as to their contents. 



