202 University of California Publications in Botany [Vol. 5 



192/08 — N. acuminata parviflora (Goodspeed. loc. cit.) 

 150/07 — N. acuminata grandiflora (ibid.) 



22/02— N. Langsdorfii (Setchell, 1912, p. 15). 

 107/01— iV. sylvestris (ibid., p. 29). 

 H18— 110/05 X 78/05. 

 H20— 78/05 X 110/05. 



The germination of the seed obtained in different years from 

 single plants of the above species and varieties of Nicotiana will 

 be dealt with in the following pages with reference first to 

 the effect of sulfuric acid treatment upon germination of seed of 

 particular strains and seed of various ages, second to the relation 

 between the age of tobacco seed and its germination and lastly 

 with reference to the germination of parent versus hybrid seed. 

 The technique involved in the obtaining of "pure" seed under 

 bag and in performing cross pollinations has been described 

 elsewhere (Goodspeed, 1912, p. 126-129) as also the methods 

 employed in cleaning the seed, sowing it, etc. Pure seed from a 

 single plant only has been employed in the germination tests in 

 the greater majority of cases and unless otherwise stated. In 

 practically every instance also and unless similarly noted the 

 seed tested was a part of that used on a given year to produce 

 the plants grown in the U. C. B. G. and thus is definitely related 

 to the various breeding experiments therein being carried on. 

 In general the seed had been stored in the laboratory in boxes 

 and similarly wrapped (Goodspeed, loc. cit.) and thus any con- 

 dition that might have increased deterioration in viability acted 

 upon all the seed in the same way. 



III. METHODS 



(a) Germinating Conditions in General 



Entirely satisfactory conditions for germination were not 

 available. The seeds were counted out on to containers of the 

 type elsewhere described (Goodspeed, loc. cit., p. 96) except that 

 in most cases finger bowls rather than drinking glasses were 

 used and thus larger surfaces were secured to hold the two hun- 

 dred seeds that were tested in the case of each plant. The seeds 

 were carefully arranged in rows in groups of one hundred seeds 

 each. This arrangement made it possible to check rapidly the 



