1916] Brandt: Notes on Trillium 59 



velops while the young shoot is growing most actively. At the time 

 of anthesis the embryo-sac is mature. In T. ovatiim the large size of 

 the ovules in midwinter and the rapidity with which the plant comes 

 into flower in spring indicate that the megaspore mother-cell divides 

 before the young shoot has appeared above ground. 



8. In Trillium grandifforum in the eastern United States and in 

 northern Germany the dormant period is approximately equal in 

 length to the dormant period in T. sessile var. giganteum in the vicinity 

 of San Francisco Bay. According to Atkinson, in T. grandiflorum 

 the pollen mother-cells are cut off and pollen may even be fully ma- 

 tured at the beginning of the dormant period, whereas in T. sessile 

 var. giganteum pollen mother-cells are cut off wdthin the dormant 

 period. In most plants of T. grandiflorum, however, maturation of 

 pollen occurs after the subterranean parts have begun to show indi- 

 cations of renewed growth. The same is true of T. sessile var. gigan- 

 teum. In T. sessile var. giganteum, just as in T. grandiflorum and 

 T. recurvatum, the megaspore mother-cell divides after the young shoot 

 has appeared above ground. In T. ovatum, on the other hand, pollen 

 is usually mature before the close of the prolonged active season, and 

 the megaspore mother-cell is apparently ready to divide two months 

 before the shoot appears above ground. 



I wish to thank Dr. T. H. Goodspeed, under whose direction the 

 work has been carried on, for his constant and valuable assistance in 

 the preparation of this paper. I also wish, among others who have 

 assisted in its preparation, especially to thank Professor W. A. Setchell. 

 I am, further, indebted to Professor R. Ruggles Gates for a number of 

 helpful suggestions and criticisms. 



Transmitted April 21, 1916. 



