344 BOTANICAL GAZETTE [APRIL 
no little value in practical agronomic tests. But he is not prepared to accept 
the author’s idea that the proposed method affords a reliable means of ‘‘ measur- 
ing the effect of crossing apart from other factors that influence yield.” The 
method does not afford a comparison between the hereditary yielding power 
(effect of genetic factors influencing yield) on the one hand, and on the other 
the effect of these same genetic factors plus the effect of crossing (heterozy- 
gosis ?). Since pronounced individual diversity exists in all ordinary maize 
varieties, the comparison offered is in reality between (1) the effect of certain 
genetic factors plus the effect of crossing between somewhat unlike individuals 
(an unknown degree of heterozygosis ?), and (2) the effect of the same genetic 
factors plus the effect of crossing between individuals presumably, though not 
necessarily, more unlike (a presumably considerable though wholly unknown 
degree of heterozygosis ?).—R. A. EMERSON. 
Aspen in reforestation.—Experimental evidence is presented by PEARSON” 
of the extent to which the aspen assists in reforestation by promoting the 
vigor of conifer seedlings. The experiments were conducted by comparing the 
survival and condition of young Douglas fir (Pseudotsuga Douglasii) planted 
on similar areas with and without aspen cover, the results being decidedly 
better in the former localities. Measurements of the evaporating power of 
the air in the two situations show it to be decidedly less among the aspens, and 
to this is ascribed the better success of the young Douglas firs. Data upon 
soil moisture are less convincing, particularly from the absence of any constant, 
such as the wilting coefficient, to determine the availability of the moisture 
which is present. Ancidentally, attention is directed to the importance of 
tati 1 in t of the aspens.—Geo. D. FULLER. 
So 
porophyte of liverworts.—Using the sporophyte of Hepaticae as a basis 
of classification, DourIn” would make three groups as follows: those with the 
sporophyte reduced to a capsule (Ricciales); those with foot and capsule only 
(Anthocerotales); and those with foot, seta, and capsule (all of the rest of the 
liverworts). Although regarding the Anthocerotales as a very natural group, 
he objects strongly to making them coordinate with Hepaticae and Mu sci. 
e reviewer’s recent studies of Mexican and Polynesian Anthony e 
especially a form from Samoa, most emphatically bear out DovumN’s vie 
OUIN concludes that the Jungermanniaceae Acrogynae, although 
divided very artificially by various writers, are a far more natural assemblage 
than are the Anacrogynae, which as now arranged are the most artificial assem- 
blage among Hepaticae.—W. J. G. LAnp 
now 
PEARSON, G. A., The réle of the aspen in the reforestation of the mountain 
burns in Arizona and New Mexico. Plant World 17:249-260. 1914. 
2 Dour, Rosert, Le sporophyte chez les Hepatiques. Rev. Gén. Botanique 24: 
403-413, 453-463. pls. 18-21. 1912. 
