80 Cayley. — Some Observations on the Life-history of 
by cross-inoculations, that copper beech could be infected by conidia of 
N. ditissima , Tub, isolated from canker on apple. He also showed that, 
although N. ditissima was generally considered to be a wound parasite, it 
was possible to infect uninjured shoots with conidia and ascospores, if the 
shoots were cut off and left without water. Under these conditions infection 
took place chiefly through the lenticels. 
Since Tulasne, a considerable amount of work has been done on the 
fungus at various times by many different investigators, the most prominent 
being Willkomm (35), Hartig (20, 21), Goethe (14-18), Lapine (24), Ader- 
hold (1, 2), Appel (3, 4), Wollenweber (3, 4, 36), Weese (33, 34), and others. 
Willkomm (35), in 18 66 , was the first to show that canker on beech trees 
was due to a fungoid parasite, but unfortunately his discovery led no 
further, as he did not definitely identify the fungus. He observed the 
conidial stage on beech and called it Fusidium Candidum. Hartig (21), 
took up the investigation in 1877 , and showed that beech canker was mainly 
due to N. ditissima , Tub, although cankerous disorganization of bark could 
be caused by frost and insect injury. On the other hand, Weese (34), one 
of the more recent investigators, who has studied the Nectriaceae from the 
systematic point of view, is of the opinion that canker in fruit and timber 
trees is due to N. galligena , Bres., and not N. ditissima , Tub (syn. 
N. coccinea ), as held to be the cause by Hartig (20, 21), Goethe (14-18), 
and Aderhold (2), and that the two fungi are biologically and morpho- 
logically distinct. Nectria galligena causes definite cankers, whereas 
N. ditissima , Tub (syn. N. coccinea), only breaks out of the bark and does 
not give rise to cankers. Weese (34) considers the most important 
characteristics which determine the variety are the formation of the 
perithecial wall and spore differences ; that the presence of a stroma or 
subiculum is not of such systematic importance as was formerly held, and 
that one and the same fungus can occur, with or without a stroma, on the 
same piece of bark. Variations as to the presence or absence of stroma 
in Hypocreaceae have also been noted by Theissen (30), v. Hoehnel (23), 
and Wollenweber (36). 
It is the opinion of the present author that the Nectria with which 
those workers were dealing — Hartig, Goethe, Aderhold, and others, who 
proved by inoculations that it gave rise to definite cankers on apple, 
beech, and other trees, and which they described under the name of 
N. ditissima , Tub — must have been N. galligena, Bres., and that the slight 
differences between the two fungi were probably overlooked. Goethe 
had doubts as to whether the fungus* with which he was concerned was 
really N. ditissima. 
The fungus described in this communication was obtained from canker 
on apple, and agrees with the description of N . galligena given by Weese (33), 
except that the ascospores, obtained from dehiscing perithecia, and measured 
