No. 5-] 1'EA A XL) XASI'L'Rrii'M SEEDS. 213 



From Table II we may collect several facts as to the rela- 

 tions in size and development between dwarf and normal 

 plants. In the first place, the ratio of height of dwarf to 

 height of normal, expressed in percentages, varies as fol- 

 lows : At two weeks, 6$'fo ; at five weeks, 36^ ; at nine 

 weeks, S 2 '/"- The ra tios between the number of leaves of the 

 dwarf and of the normal are 58'^; and 56^ for the two and five 

 weeks old plants, respectively. No readings were made of the 

 number of leaves at the third stage, because some of the plants 

 had lost leaves, and the oldest leaves of all the plants were 

 beginning to wither, so that the number had not as much 

 significance as in the earlier stages. Similar measurements 

 of height and number of leaves made on another lot of peas 

 showed similar variations in ratios, so we may consider the 

 readings here given as typical. The advantage in size, then, 

 which the normal seedlings show in the first stage becomes 

 more marked as the plants grow older, while the differentia- 

 tion, so far as expressed by the number of leaves, though 

 markedly greater in the normal than in the dwarf plant, does 

 not increase much faster in proportion in the former than in 

 the latter. The time of the first appearance of flowers is, how- 

 ever, more significant of the differentiation of the plant than is 

 the number of leaves, for the latter may depend on the size of 

 the plant, as well as on its degree of development. The time 

 of flowering was unmistakably earlier in the normal plants, for 

 the first flower appeared upon them at five weeks, whereas the 

 first flowers appeared on the dwarf plants at eight weeks. At 

 this time three dwarf plants blossomed, while during the 

 same period five of the normal plants had borne flowers, of 

 which three had developed into pods. These facts suggest 

 the conclusion that the normal plants not only are larger 

 than are the dwarf plants but develop more quickly than do 

 the latter. 



It remains, therefore, to be seen whether the foregoing con- 

 clusions to which the macroscopic examination has led are 

 supported by the examinations of sections under the micro- 

 scope. An examination of this sort may be looked to to 

 answer the following four questions: 



