^64 Journal of Agricultural Research voi. xvm. no. n 



ASTKR UNARIIFOUUS L. 



A common wild aster found in dry, open situations from Maine to 

 Wisconsin and southward. The normal blossoming period begins about 

 September i and extends over a period of two or three months. 



(i) Exposed to light from 9 a. m. to 4 p. m. Six individuals taken 

 from the field May 13 and transplanted to boxes of the type used for 

 soybeans, three plants to the box. One box of the plants placed at once 

 in the dark house. The control plants soon resumed vegetative develop- 

 ment, throwing out numerous axillary branches on the upper portion 

 of the stems as the normal limit in height was approached, thus following 

 the regular course of development in the field. The test plants, on the 

 other hand, made little additional growth and by June i were showing 

 tiny flower heads. First blossoms appeared June 18 on test plants and 

 September 12 on controls. Average height of test plants on June 24, 

 8 to 10 inches and that of controls 14 to 15 inches. Test plants were 

 permanently returned to normal light on June 20. See Plate 72, B. 



(2) Exposed to light from 6 a. m. to 6 p. m. Three individuals trans- 

 planted from field to each of two 8-gallon iron cans June 10 and those in 

 one can placed in dark house June 12. Tiny flower heads were showing 

 on the test plants by July 2. First blossoms appeared July 19 on test 

 plants and September 20 on controls. Average height of test plants 8 

 to 9 inches and that of controls 14 to 15 inches. 



(3) Exposed to light from daylight to 10 a. m. and from 2 p. m. to 

 darkness. Three individuals transplanted from the field to each of two 

 8-gallon iron cans on June 14 and those in one can placed in dark house 

 June 16. Flower heads were showing on both test plants and controls 

 by August 20. First blossoms appeared September 16 on test plants 

 and September 18 on controls. Average height of test plants 11 to 12 

 inches and that of controls 14 to 15 inches. 



CLIMBING HEMPWEED (mIKANIA SCANDENS, L.) 



A climbing composite, ranging from southern Maine to Florida and 

 westward to Ontario, Mississippi, and Texas. The normal blooming 

 period extends from late July to the latter part of September. The 

 aerial summer growth perishes in the fall, and the plants are carried 

 over the winter period by perennial underground shoots. 



(i) Exposed to light from 9 a. m. to 4 p. m. A number of roots were 

 transplanted from the field to 6-inch pots and placed in the greenhouse 

 in November, 191 8. These roots threw up shoots which made con- 

 siderable growth during the winter months but did not blossom. On 

 June 3 one plant was transferred to each of six 12-quart iron pails, three 

 of which were placed in the dark house at once. The controls began 

 blossoming in late July and continued to blossom profusely till the latter 

 part of September. Some of the plants which had been left in the green- 



