46 I' nii'( r.silij of Calif orn'ui l*uhUcations in Botunij [Vol. 7 



stock. Plants with three or four slioots are always in ihc minority, 

 whereas there seems to hv no limit to the inmihei- of shoots that a 

 single rootstock of T. sessile var. giganteum may send up, eight having 

 been seen in one specimen. 



In addition to tlie ])ai'ts eninneraled al)Ove, the i-ootstock of T. 

 sessile var. giganteum very frequently has one oi- more young root- 

 stocks growing out from it as lateral branches or ''offsets." These 

 increase their diameter from year to year, build up their own root 

 systems, and by decay of the older portions of the rootstock soon be- 

 come independent plants. In this way a single plant often in time 

 produces a clumj) of a dozen or more. On the other hand, T. ovaium 

 very rarely produces an otTset (cf. Kerner and Oliver, 1895, pp. 452- 

 454). The general significance of vegetative reproduction in Trillium 

 species has been fully discussed in a previous report (Goodspeed and 

 Brandt, 1916, o). 



Foerste (1891) states that the Eastern or type form of T. sessile 

 L. is characterized by a horizontal rootstock, and refers to the orien- 

 tation of the rootstock by the contraction of the roots. He also states 

 that in early wdnter there are buds present in the rootstock crow'n for 

 tw^o active seasons in advance. 



III. The Active Period, February to July 



1. ABOVE GROUND 

 a. Trillium sessile var. giganteum 



In a previous report (1916, a) we have fully outlined the climatic 

 conditions under which plants in western middle California pass their 

 annual life-cycles. A number of the points there emphasized are of 

 importance in the following discussion and will be briefly referred to. 



Trillium sessile var. giganteum appears above ground in the latter 

 part of January and in February. This species has withered and in 

 almost all cases disappeared by the end of July. For convenience 1 

 have chosen to regard this period — February to July — which includes 

 the life of the plant above ground as equivalent to th(^ ''active" period. 

 It is of course obvious that the active period of growth and flowering 

 occupies a considerably shorter interval. How-ever, the period chosen 

 covers the interval fi-om the appearance of the green shoot to the 

 shedding of seed, and therefore marks the life-cycle above ground. 



When the young shoot first appears above ground the leaves are 

 tightly rolled into a cone about lln^ flower-bud. In some plants the 



