1916] Brandt: Notes on Trillium 47 



leaves are imbricated in the bud, in others convohite, the species ap- 

 parently not adhering to one arrangement. The characteristic colors 

 of the various aerial parts are variable in the time of their appearance. 

 As the shoot emerges, the leaves and sepals rapidly change from deep 

 yellow to green, while the petals attain their full coloration only -when 

 entirely exposed to the light and free from the enveloping sepals and 

 leaves. The stamens are heavily pigmented, showing almost their full 

 coloration a short time before the flower unfolds. 



From the first appearance of the tip of the shoot above ground 

 to the complete emerging of the tightly rolled cone of leaxes approxi- 

 mately a week intervenes. Thereafter growth is rapid until the 

 maximum length of stem is reached. Measurements made on devel- 

 oping plants in the University of California Botanical Garden, and 

 field notes, provide the basis for this statement. Almost with the 

 start of this rapid growth to increase the length of the stem a loosening 

 of the cone of leaves is evident, and as growth proceeds the unfolding 

 of the leaves is sufficiently rapid so that they are completely flattened 

 shortly after the maximum height is attained. This gradual unfolding 

 and flattening of the leaves is accompanied by a sufficient increase in 

 size so that they are nearly mature, so far as growth and expansion 

 are concerned, when the stem has attained its full height. In general 

 it might be said that this period of rapid growth occupies, in average 

 cases, a little more than two weeks. 



The significant stages in the development of the flower take place 

 subsequent to the complete unfolding of the leaves. The sepals are 

 practically full size at this time and are pushed apart by the rapid 

 growth of the petals, which are hardly in sight within the sepals when 

 the leaves first unfold. The petals are fully mature and the flower 

 unfolds approximately three weeks after the shoot first appears. 

 Owing to the method of dehiscence of the pollen sacs, anthesis may 

 follow immediately or after an interval of more than a week, according 

 to atmospheric conditions. Dehiscence is accomplished by the mere 

 straightening of the walls of the locules, caused by the epidermis 

 contracting more than the endothecium. The locules may remain 

 distinct until anthesis, in which case a zone of small-celled tissue is 

 developed between the locules (see pi. 10, fig. 2), or they may become 

 fused into one by the disintegration of the parenchyma between and 

 back of them, but this is not essential to dehiscence. It can be shown 

 that anthers from unopened flower-buds may dehisce within an hour 

 in the dry air of the laboratory. 



