1912] Goodspeed: Nicotiana Ilyhrids 91 



III. DIVISION OF F, HYBRID SEED 



The technique and methods in obtaining pure seed, perform- 

 ing the cross-pollinations and the cleaning and sowing of the 

 seed, has been fully described elsewhere in this combined paper 

 (pp. 126-131). The parent plants were crossed during August, 

 1909, and the hybrid plants produced from the seed of this 

 cross, and which yielded the experimental material, w^ere grown 

 during the summer and fall of 1910. 



When the seed, produced by self- (close) fertilizing one of 

 the plants of this hybrid, was" cleaned in January, 1911, there 

 were five ripe and well-seasoned capsules in the bag. During 

 February, 1911, the seed of this one plant was examined for 

 size, color and weight as follows. 



1. Size and Shape 



Under the lens the seed presented a characteristic appearance 

 in all instances. The shape was more or less oval to flattened 

 pear-shape, with the funiculus often forming a little hook at 

 the smaller end of the seed. In most cases, also, a seam was 

 to be seen running from the short funicle for some distance 

 around the seed soon to fade, however, into the pimply seed- 

 covering. This pimply appearance is caused by a great number 

 of sharply raised points occuring on the surface of the seed 

 coat, which thus appears quite rough under a low magnifica- 

 tion. Under a considerable magnification these raised points were 

 seen to be connected with one another by fine, much curved and 

 twisted, thread-like lines. Under the lens an arbitrary division 

 was made according to size into (1) large, (2) intermediate, 



(3) small — all of these were w^ell filled out, plump seed — and 



(4) ill-formed, flattened and wrinkled seed. The seed placed 

 in division 4 presented a great variation in appearance, from large 

 seed coats, so flattened as to appear empty, to very small seeds 

 with simply much wrinkled coatings. The average length, 

 breadth and the length-breadth index for the seed of grades 

 1, 2 and 3 are given in the following table: 



