428 BOTANICAL GAZETTE [December 



characters in common. Before flowering they can be distinguished 

 with certainty only when the environmental conditions are the 

 same for both. Thus, mut. revoluta grown in a rich, moist soil is 

 as large as mut. formosa grown in a dry, sandy soil. Under such 

 conditions they might be indistinguishable until they flowered, 

 when the latter would produce large capsules, filled with good 

 seeds, and the former would produce few seeds or none in the 

 shriveled ovaries. Grown under identical conditions, however, the 

 two mutations differ at every stage of development. In some 

 features mut. setacea also appears to be a reduction derivative in 

 the same series with mut. formosa and mut. revoluta. In compari- 

 son with the latter, however, it shows a partial resumption of fertil- 

 ity. Its large, strong capsules are well filled, although the seeds 

 are for the most part empty. In this characteristic, as also in its 

 simple inflorescences and thick-tissued buds and flowers, it resembles 

 mut. albicans. Mut. setacea is different from the other three muta- 

 tions in its strong tendency to produce dimorphic foliage. The 

 rosette leaves and young cauHne plants have narrowly linear, 

 grasslike leaves, which are succeeded above and on the inflorescence- 

 bearing lateral branches by leaves much like those of mut. revoluta, 

 which nearly always show the setiform terminal appendage. Like 

 the latter mutation, mut. setacea responds greatly to enviroiunental 

 changes. In dry sandy soil it flowers and fruits when only lo cm. 

 high, but in moist loam it becomes 50 cm. high and has quite a 

 different aspect. The comparatively broad-leaved mut. albicans 

 is totally unlike the other mutations at every stage of development. 



THE Pi, F2, AND T, PROGENIES OF FORMA typica 



The original wild mother plant designated as Lexington E did 

 not give a progeny in any way pecuHar when it was first grown 

 in 1913. A casual inspection of the Fi seedlings disclosed no 

 mutations. The majority of the plants of this first culture were 

 discarded as very young seedhngs and only 30 were brought to 

 maturity. These 30 plants were entirely typical. In 19 14 the F2 

 of the strain was found to show mass mutation. The remaining 

 seeds of the original collection were therefore sown, in order to 

 detect any mutability which, on account of the use of insufficiently 



