1916] Goodspeed-Brandi: Notes on Trillium 33 



flowers is thus tentatively assigned to a lack of sufficient development 

 of flower parts at the period when the products of metabolic activity 

 stored in the rootstock are for a time shifted almost wholly to the 

 reproductive tissues for their rapid development. A seedling root- 

 stock or young offset is thus to be thought of as capable of maintaining 

 nothing more than a vegetative existence above ground, a balance of 

 available food properly to mature floral organs being accumulated 

 in small amounts each year until after a variable but usually con- 

 siderable number of years a normal in place of an undeveloped flower 

 is produced. This explanation apparently covers such a case as that 

 of rootstock 39 in table 2, since a rootstock which has successfully 

 produced shoots should, other things being equal, be successful in 

 passing from the condition of undeveloped to normal flower more 

 rapidly than a seedling rootstock or offset which has never succeeded 

 in producing a normal flower. The abrupt transition from normal to 

 undeveloped flower production may be taken to be due similarly to 

 a disturbance of metabolic relations, the most obvious of which is 

 the taking up of a normally flowering rootstock during the height 

 of its active period above ground. Such treatment almost invariably 

 results in the production by it of an undeveloped flower in the follow- 

 ing season. 



In general, of course, the production of undeveloped flowers may 

 be taken as an extreme instance of the sterility commonly seen in 

 normally flowering plants of T. sessile var. giganteum, which produce 

 very little viable seed and in which the pollen may be highly defective 

 or the development of the pistil entirely suppressed. That the sterility 

 found in normally flowering plants and expressed in its extreme form 

 in the production of undeveloped flowers may be assigned to condi- 

 tions of nutrition and available food-supply is at least suggested by 

 a comparison of the reproductive methods of two distinct Californian 

 species — T. sessile var. giganteum and T. ovatum. In the former, 

 as we have seen, undeveloped flower production and sterility in 

 normal flowers is common and here vegetative reproduction is im- 

 portant and very vigorously carried on (cf. Goodspeed and Brandt, 

 1916). In T. ovatum, on the other hand, viable seed is formed in 

 a majority of the normal flowers ; and undeveloped flowers, while 

 common, are not produced in such amount, and finally we have hardly 

 succeeded in finding a single instance of vegetative reproduction by 

 offsets. 



A variety of experiments are contemplated in an attempt to gain 



