No. 5.] PEA AND NASTURTli'M .S7-V-./AS'. 211 



of the nasturtiums vary from 10 to 41, with more than half 

 the individuals between i6'/i. and 25'^, and nearly three- 

 quarters between i6'/(, and 30'^. The chances, then, that 

 from (>5'/ to 74'^ of the bulk of any pea seed has been 

 removed, are even ; and the chances are three to one that 

 from /o'/r to 84/1- of any nasturtium seed has been removed. 



The variation in the amount of cotyledon removed appeared 

 to influence the rate of growth of the seedling, but the num- 

 ber of plants of which a quantitative record of the develop- 

 ment was kept was too small to justify an attempt to lay down 

 a rule concerning the extent of this influence. The seedlings 

 will therefore be regarded as belonging to only two classes, 

 the normal and the dwarf, the latter composed of plants 

 growing from seeds that have been reduced by removing part 

 of their cotyledons. Plants of the two classes sprouted at 

 about the same time, and for a short time the differences 

 between them were not striking. As soon, however, as 

 leaves began to develop, the normal seedlings shot ahead, 

 surpassing the dwarf seedlings not only in size, but also in the 

 number and size of their leaves. A comparison of two groups 

 of pea plants, as given in Table II, from readings taken at 

 three different times, shows the relative rate of develop- 

 ment. The figures represent the height of the plants in 

 millimeters and their number of leaves, while at the foot of 

 each column is placed the average of the readings in that 

 column. The readings from the dwarf seeds are arranged in 

 the order of the fraction of the seed that is used for planting, 

 and the readings from the normal seeds, in the order of the 

 weight of the seeds, the smallest fraction and the smallest 

 weight being at the top of their respective columns. The first 

 period, two weeks after the seeds were planted, corresponds to 

 an early stage of development ; the second, five weeks old, is 

 the stage just before the production of flowers by the normal 

 plant ; and the third period, nine weeks old, is the period of 

 maturity, when the plants are bearing flowers and seeds. The 

 letters fl. and the word pod in the column marked "leaves," 

 mean that the plant against which they are placed has a flower 

 or a seed-pod. 



