1916] Brandt: Notes on Trillium 57 



tinues in this binucleate condition for two weeks or more {loc. cit., 

 p. 20). 



h. Trillium ovatum 

 As noted above, T. ovatum matures its pollen earlier in the season 

 than T. sessile var. giganteum. In general the pollen mother-cells 

 divide during August and September, and pollen is apparently mature 

 in all plants by the first of November. By the latter part of December 

 nucellus and integuments apparently have attained nearly their mature 

 size, and it seems probable that growth of the female gametophyte 

 begins before the shoot appears above ground. As in T. grandiflorum, 

 the megaspore mother-cell in T. ovatum^ becomes centrally located in 

 the nucellus. 



V. Summary 



1. The underground structures of a Trillium plant consist of a 

 stout subterranean stem, or rootstock, bearing perennial roots and a 

 large terminal bud. As the rootstock adds live tissue at its growing 

 end from year to year the basal end decays. Thus at any one time 

 the rootstock, instead of representing the actual age of the plant, rep- 

 resents only a portion of its age, three to fifteen years, according to the 

 rate of decay. 



From two to five or more roots are sent out each season, according 

 to the size and vigor of the plant, and live from two to ten years. By 

 contraction they draw the rootstock down into the ground, and, usually 

 in the case of T. ovatum Pursh, sometimes in T. sessile var. giganteum 

 H. & A., orient it in a horizontal direction. 



The terminal bud in September contains not only the young stem- 

 buds for the next growing season but also two or more young stem- 

 buds for the second season in advance. Usually the first of these 

 stem-buds, which already has cut off the primordia of lateral organs, 

 fails to develop farther. Each stem-bud is formed in the base of a 

 fleshy scale-like body which in turn arises in the axil of a bud-scale 

 or sheath. At least a rudimentary stem-bud is found in the axil of 

 every bud-scale. 



The rootstock of T. sessile var. giganteum bears lateral branches or 

 offsets, which in time become separated by decay of tissue from the 

 parent plant, thereby affording a ready means of vegetative repro- 

 duction. Such offsets are rarely found in T. ovatum. 



