342 
GENETICS: T. H. GOODSPEED 
sions.' Certain species-crosses in Nicotiana made by Gartner, also, gave 
seed that produced the mother species as well as true hybrids. These 
latter observations have been explained by the assumption that cross 
pollinations, 'by the extraordinary irritation of foreign pollen' (East, 
I.e.), may induce an apogamic or parthenogenetic development of a 
portion of or all of the ovules affected. Wellington, by a variety of 
stimulations and irritations of immature tobacco flowers was able to 
produce 'some abortive seed without embryos' while from a consider- 
able number of simple castrations of buds, viable seed was produced 
in only one doubtful case. Our own results, based upon over 1500 cas- 
trations of tobacco flowers, borne on many species and varieties of 
Nicotiana in the University of California Botanical Garden, are entirely 
negative. No viable seed without pollination has been produced and 
in the appearance of numerous hybrid progenies we have, in no case, 
had reason to assume the production of apogamic or parthenogenetic 
seed as a result of cross pollination. 
On the assumption, then, that errors of technique will not entirely 
account for the results which Mrs. Thomas obtained, it appeared pos- 
sible that the production of viable seed without pollination was actu- 
ally peculiar to certain of the particular strains of tobacco which she 
possessed. Faulty technique has been the only explanation offered to 
account for the unusual results which Mrs. Thomas reported while, so 
far as I know, no one has attempted to repeat her experiments with the 
strains of tobacco she used. Seed of the Nicotiana Tahacum variety, 
described in her paper as a frequent producer of seed without pollina- 
tion, was kindly sent me by Mrs. Thomas. On plants from this same 
seed Bateson^ confirmed Mrs. Thomas' results. The seed was received 
under the name ' Nic. tahaccum Cuba' and represented a portion of the 
original seed 'gathered in the Garden of Casa Loring at Malaga in 1908.' 
Ninety-five plants were grown from this seed during 1914. The stand 
was entirely uniform and the plants were taller than and as vigorous 
as any of the N. Tahacum varieties in our cultures (cf. SetchelP). As 
described by Mrs. Thomas (loc. cit.) they are white-fiowered plants, 
considerable numbers of four-parted flowers being produced especially 
at the opening of the flowering season. In vegetative characters they 
resemble the commercial types collectively known as 'Cuban Tobacco.' 
Eight hundred buds on these ninety-five plants of ^Nic. tahaccum 
Cuba' were treated according to one of the following methods — (1) 
simple emasculation of the flower by picking off the anthers near the 
tops of the filaments, (2) castration of the bud plus the pinching off, 
with the forceps, of the stigma at the very top of the style and (3) pinch- 
