1915] Goodspeed: Parthenogenesis, Parthenocarpy, Phenospermy 269 



Summary 



The above report has to do primarily with a white flowered variety 

 of N. Tahacum the seed of which was received under the name "Nic. 

 tahaccum Cuba." This is the variety in which ]\Irs. R. H. Thomas 

 found parthenogenesis to be of such frequent occurrence. 



1. Over 1500 attempts to produce partheuogenetic seed on a con- 

 siderable number of species and varieties of Nicotiana have yielded 

 entirely negative results. 



2. In a considerable number of distinct hybrids made between 

 such Nicotiana species and varieties and grown in some cases through 

 five hybrid generations, no evidence has been furnished that the pos- 

 sible irritating and stimulating effect of cross-pollination has resulted 

 in the production of any partheuogenetic or apogamous seed. 



3. Approximately 800 castrations and mutilations of buds borne 

 on plants of ^'Nic. talacctim Cuba" produced over 100 normally 

 matured fruits. Following the majority of these 800 castrations and 

 mutilations, the flowers and maturing capsules, though ultimately 

 they may have fallen, remained attached to the plant for much longer 

 periods of time than is the case in other species and varieties of 

 Nicotiana when similar treatment is applied. 



4. In the majority of these parthenocarpic fruits empty seeds 

 were produced in great numbers. Some were as large as the self- 

 fertilized seed of the same plant, though the majority were smaller. 

 Few flattened or shrivelled seeds were formed. 



5. For this type of seed production, either with or without pol- 

 lination, the term phenospermy is suggested. It is taken to be 

 synonymous with the terms "abortive" and "empty" that have 

 been elsewhere applied in describing such seeds. 



6. Approximately 50 seeds were found in nine of the partheno- 

 carpic fruits, some of which exhibited normally matured endosperm 

 and embryos when the color of the seed coats was bleached out with 

 Eau de Javelle and some of which germinated normally and have 

 produced normal seedlings. Six seedlings are at present of fair 

 size from 18 seeds germinated. 



7. A small portion of the seed from the parthenocarpic fruits was 

 neither partheuogenetic nor phonnspcrmic, luit contained traces of 

 endosperm only. 



