EXPERIMENT STATlOxN KIOl'OKT. 413 



cotyledons. A microscopic examination showed that the greater thick- 

 ness was dne to increased size of the cells instead of to a multiplica- 

 tion of the layers. The chlorophyll was excessive and the amount of 

 starch so great as to practically render them black when blanched with 

 alcohol and iodized. The roots grew to nearly market size, and had 

 .the tests been made with a turnip-shaped sort instead of a long variet}', 

 it is very likely that the roots would have been fit for the table. See 

 1, Plate IX. 



The second species was the common morning-glory {Ipomvea pur- 

 purea). Here the cotyledons are large in the seedling, but quickly 

 axe lost from sight by the development of the much larger alternate 

 true leaves. After holding on for a few days, as a rule, the cotyledons 

 lose their green color and drop from the stem. In the deplumuled 

 seedlings petioles at once begin to elongate, as was shown to be true 

 with the radish, A\hile the remarkable green develops in the blades, 

 that like^wise become double or more the normal size and l>ecome 

 the organs of photo-synthesis from the mutilated plant. Their dark 

 green is shared by the long, arched petioles (quite different in this re- 

 spect from those of the radish) and the hypocotyle. The latter be- 

 comes of t^nce the sectional area of the normal plants, that are now 

 several feet high and bearing flowers and become a store-house for 

 the starch, that is robljed of its proper use by the al^sence of any stem. 

 The root system of the deplumuled plant is not different from that 

 of the normal specimens. See 2, Plate IX. 



A third type of plant put to the test is the Hubbard squash, the 

 seedlings of which naturally have large cotyledons. In these the seed 

 leaves remain near the soil, without any apparent elongation of the 

 hypocotyle, but there is a remarkable increase in the size of the coty- 

 ledons, until they are sometimes four or more inches in length and 

 very odd, to say the least. Normally, the true leaves come forth from 

 the pumule rapidly, and, due to their large size, the cotyledons are soon 

 out of sight and quickly wither away. Dwarfed squash plants, de- 

 pending entirely upon the cotyledons, have been kept in apparently 

 healthy condition for four months, the size remaining practically the 

 same after the first four weeks. These plants, unlike those previously 

 mentioned, need frequent attention, for buds will develop in the axils 

 of the seed leaves, which, when removed, will be followed by others 

 without any determined number. If left undisturbed a whole thick 

 cluster of stems and small leaves will develop. See 3, Plate IX. 



