TORREYA 



June, igi6. 

 Vol. i6 No. 6 



ECOLOGIC NOTES ON DROSERA ANNUA 



By E. L. Reed 



In the spring of 1914 while on a field trip, near College Station, 

 Texas, the writer observed some specimens of Drosera growing 

 in an open oak wood that is invading an abandoned field. The 

 habitat was a gentle slope of what appeared to be a comparatively 

 dry, sandy soil. The Drosera in question, upon further examina- 

 tion, proved to be a new species to which the name D. annua 

 was given.* Later a number of other stations of the same 

 general character were observed and D. annua was found to be 

 quite common in the vicinity of the college. In this region the 

 plant was never found in or near ponds or streams; in the eastern 

 part of the state, however, it sometimes grows in moist sand near 

 ponds but has not been reported as growing in or at the edge of 

 bodies of water. Since such a habitat for species of Drosera 

 was unusual, an ecologic study was begun, in order to determine 

 the environmental conditions under which it grows. 



The climate of this region is warm temperate, or perhaps, 

 subtropical, and is divided generally into a wet and a dry season. 

 The former begins about the middle of November and extends 

 well into March. It in turn may be divided into three periods, 

 two of heavy rainfall separated by one of light rainfall. The 

 first period of heavy rainfall extends to about the beginning of 

 January; in January the precipitation is light, while the second 

 wet period is from about the first of February to the end of Alarch. 

 The summer season is usually one of slight rainfall. The early 



[No. 5, \'ol. 16, of ToRREYA, comprising pp. 103-124, was issued 24 May 1916.] 



* Reed, E. L., Drosera annua, sp. nov. Torreya, \'o1. 15, Xo. 11, November. 

 1915- 



125 



