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with the shelled rhizopod Difflugia, states that most of the work on uni- 
parental reproduction has yielded the result that during such reproduction 
the hereditary constitution (genotype) appears not to change though the 
organism may differ much in outward character. Many papers cited 
support this view though some are opposed. Jennings says with regard to 
his own results: ‘After many generations of descent from a single progenitor, 
such a single family . . . . has differentiated into many _he- 
reditarily diverse stocks.’’ These diverse stocks differ hereditarily not only 
with respect to particular single characters but also with respect to the 
combination of characters. Many individuals of uniparental reproduc- 
tion have shown a marked permanence of hereditary character in single 
lines of descent, all the progeny being like the parent in hereditary consti- 
tution; and further, many such lines, diverse in hereditary constitution may 
exist in a population, and the effects of selection consist mainly, if not 
entirely, in the isolation of such diverse lines. 
East sees no reason to believe bud variation different from germinal 
mutation and says that it may be progressive, digressive, or retrogressive. 
Bateson (10) holds that bud variations are due to qualitative cell-division 
in somatic tissues, giving somatic segregation of unit factors. East points 
out that in the large majority of cases of bud variation there has been 
simply the loss of a dominant character and hence the appearance of a re- 
lated recessive character. In some cases there is absolute disappearance 
of the dominant character; in other cases it appears to be latent, and it may 
reappear. Variations in color constitute over 70% of all bud variation. 
Colony color in Helminthosporium is also a very common variable but 
this is, in all probability, entirely incomparable with color variation in 
flowering plants. 
Brierley (28) holds, for Botrytis, that even if sexuality occurs, the 
fungus is “‘on all evidential criteria, an asexual homozygotic organism in 
which the isolation of a single spore strain necessarily implies the isolation 
of a ‘pure line’’’. Aan A genotypic change in a pure line is a 
mutation.”’ Similarly, Shear and Wood (105) regard individuals orig- 
inating from single spores of Glomerella as homozygous, though on reason- 
ing differing somewhat from that of Brierley. Crabill (36) also holds that 
since his fungus “‘reproduces asexually segregation from heterozygous 
parents cannot explain the origin of the strains.’’ Accepting Brierley’s 
criteria, my Helminthosporium single-spore isolations are equally homo- 
zygotic. In at least three forms on cereals Helminthosporium is known 
to be the conidial stage of the ascigerous genus Pleospora. As ascigerous 
