5 CIRCULAR 863, U. S. DEPARTMENT OF AGRICULTURE 



H. L. Hyland and R. E. Stitt, in unpublished annual reports, have 

 noted wide variation in the number of apetalous flowers produced 

 on different plants. The percentage of apetalous flowers varied 

 from 30 to 100 of the total number of flowers produced. While 

 different inheritance patterns are evident in the plants studied, 

 it was concluded that the environmental factors, temperature and 

 light, largely govern the development of apetalous flowers. 



CLIMATIC AND SOIL ADAPTATION 



To delimit precisely the climatic and soil adaptation of this crop 

 is not yet possible. It has survived several seasons in southern 

 Vermont and southern Michigan and has been known to survive 

 winter temperatures of —17° F. On the other hand, it has gone 

 out or has been severely injured in sections with less severe winter 

 conditions. The variation in results may be due to differences 

 in heaving, or in ground cover, snow, or debris. It has been ob- 

 served that plants in cultivated rows suffered more than those 

 in broadcast stand. Buds that are stimulated by warm days 

 in February may be killed by a subsequent drop in temperature. 

 Sericea is as sensitive to cold while in a growing condition as any 

 species of lespedeza. In the South a stand may start growth 

 early and become several inches high only to be cut down by a 

 late freeze. This does not kill the plants, however, but cuts down 

 the new growth. 



Sericea is also affected by length of day. It does not seed 

 where the days are too long, as in Oregon. In southern Michigan 

 it has been known to seed sparingly. In an experiment by the 

 Bureau of Plant Industry, begun March 4, 1936, at Washington, 

 D. C, three plants, originally the same size, were grown under 

 different lengths of day. One plant was grown under artificial 

 light until 11 p. m. ; a second under a normal day; and a third 

 under a short or 8-hour day. In 1 month the first plant grew to 

 17 inches, the second to 9 inches, and the third to 6 inches. 

 Figure 4 shows the results after 9 months. 



While sericea will endure extreme drought when well estab- 

 lished, it is in no sense a dry-land plant. The fact that it makes 

 little growth during the cool, moist spring subjects it to extreme 

 hardships caused by droughts in summer. At Hays, Kans., it 

 has lived for several years but has not made growth enough to 

 compete with sweetclover and alfalfa, which can take full ad- 

 vantage of the spring moisture. As far as present knowledge 

 goes, therefore, sericea would appear to be a plant for the territory 

 from perhaps a hundred miles north of the Ohio River to the 

 Gulf of Mexico and from the Atlantic to central Kansas and 

 Oklahoma. 



Sericea thrives best on clay and silt loams but has made good 

 growth on sands and sandy loams and has done well on some acid 

 muck soils. Its best growth is apparently made on soils on 

 which it is most needed, namely the poor, eroded clays, clay 

 loams, or silt loams of the Piedmont and on similar soils else- 



