208 University of California Publications in Botany [Vol. 5 



The extremely low pet'eentage of total germination in the ease 

 of 1912 150/07 is rather surprising, but in the table on page 212 

 it will be seen that the 1912 seeds of 53/03 and 192/08— the 

 other two N. acuminata-vsirieties cultivated in the U. C. B. G. — 

 also showed a remarkably low per cent of total germination. In 

 general no difficulty has been experienced in past j^ears in secur- 

 ing a fairly high per cent of germination in the case of N. acumi- 

 7ia^a-varieties under the germinating conditions elsewhere de- 

 scribed (Goodspeed, 1912, pages 98 and 132), although under 

 such conditions germination in X. acuminata has always been 

 slow as compared with practically all the other Nicotiana species 

 grown. In the case of 1912 53/03, 192/08 and 150/07 the 

 seed was taken from the ripe and opened capsules on the plants 

 and did not lie in the seed packets for four or five months as 

 is the rule where the seed is sown in March or April following 

 the gathering of the seed in November or December. This period 

 of ''after ripening" or further drying of the seed of N. acumi- 

 nata-vavieties may be essential for a high percentage of germina- 

 tion of their seed under experimental conditions. It is also 

 entirely possible that conditions for germination in the case of the 

 seed of N. aciiminata-varieties may be more favorable when the 

 seed is sown in soil and placed in an unheated propagating house 

 in which the variation in daily temperature covers a wide range. 

 In this connection the striking increase in germination when this 

 1912 150/07 seed is treated with 80 per cent sulfuric acid for 

 five minutes and the acid washed off for forty-five minutes in 

 running water is unusually significant. The effect of prolonged 

 washing after treatment with sulfuric acid is brought out in the 

 above table (table 2). As will be seen there in the case of 1912 

 150/07 when washed in running water for forty-five minutes one 

 of the duplicate tests showed 53 per cent germination, while the 

 other similarly treated but washed for twenty hours gave only 

 29 per cent germination. A .similar injurious effect of prolonged 

 washing after sulfuric acid treatment has been noted by Love 

 and Leighty doc. cit., p. 314). Additional tests further taking 

 up this particular point are in progress. 



It seems thus possible on the basis of these relatively few 

 preliminary tests to state that a marked benefit is to be derived 



