566 Journal of Agricultural Research voi. xviii, no. n 



of them measured nearly 4 inches in diameter while its rosette of leaves 

 measured 30 inches from tip to tip. Flower stems did not develop. The 

 controls grew more rapidly from the outset, and all except three or four 

 to be considered later formed flower stems in June, the first blossom 

 appearing June 21. See Plate 75, B. 



CARROT (DAUCUS CAROTA L,.) 

 OXHEART:' 



Exposed to light from 9 a. m. to 4 p. m. Planted June 4 and at once 

 placed in dark house. The test plants made a uniform but slow growth, 

 and the roots, which were very small, appeared to be devoid of the yellow 

 pigment, carotin, since they were almost snow-white in color. The con- 

 trols grew and developed normally, the roots showing the normal yellow 

 color. On August 1 9 the average height of the test plants was 8 to 9 

 inches and that of the controls 18 to 20 inches. See Plate 79, B. 



LETTUCE (ivACTUCA SATIVA h.) 



BiyACK Seeded Summer:^ 



Exposed to light from 9 a. m. to 4 p. m. Planted in dark house 

 June 4. Germination was satisfactory, but the seedlings made very 

 little growth, and after a time all died. The controls grew vigorously 

 but under the stimulus of the long day the plants soon sent up flowering 

 shoots and blossomed. 



HIBISCUS MOSCHEUTOS L. 



A wild perennial in marshes, ranging from Ontario to Florida and 

 Texas. Normal blooming period July to September. Exposed to 

 light from 9 a. m. to 4 p. m. Planted in November in greenhouse. Seed 

 did not germinate till the following March. Seven plants transferred to 

 i2-quart iron pails on June 6, three of which were placed in dark house 

 June 7. The test plants did not blossom nor did they make any growth 

 during the summer. The controls grew vigorously, and the first blossoms 

 appeared August 22 to September 10. The average height of the test 

 plants was 12 inches and that of the controls 29 inches. 



CABBAGE (bRASSICA OEERACEA CAPITATA h.) 



Early Jersey Wakefield:^ 



Exposed to light from 9 a. m. to 4 p. m. Observations based on 

 four test plants and four controls. Transplanted and placed in dark 

 house on June 7. The test plants grew slowly but uninterruptedly 

 throughout the season, although they showed little tendency to form 

 heads. The control plants grew normally and formed large heads which 

 eventually burst open, followed by the formation of new heads of small 

 size. 



' Horticultural variety. 



