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 cauline 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 environmental 
changes. In dry sandy soil it flowers and fruits when only to cm. 
high, but in moist loam it becomes 50cm. 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 F;, F2., AND F; PROGENIES OF FORMA typica 
The original wild mother plant designated as Lexington E did 
not give a progeny in any way peculiar when it was first grown 
in 1913. A casual inspection of the F, seedlings disclosed no 
mutations. The majority of the plants of this first culture were 
discarded as very young seedlings and only 30 were brought to 
maturity. These 30 plants were entirely typical. In 1914 the F, 
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 
