° 
ENDOTHIA PARASITICA AND RELATED SPECIES. 29 
Development of the stromata.—The writers have not followed the 
development of the stromata in culture, but an examination of nu- 
merous sections of E'ndothia singularis, E. gyrosa, E’. fluens, and E. 
parasitica and a study of the three latter species under field condi- 
tions on various hosts shows that their development is by no means 
as uniform as indicated in Anderson’s description (1). 
According to Anderson, the pycnidium develops first, and about 
the young pycnidium the stroma is quickly formed, while the 
perithecia arise later, usually in the lower portion of the stroma. 
This may perhaps be considered the typical course of development, 
and pycnidia are often found above the perithecia, but all variations 
occur. <A large stroma may be developed without a sign of a pyc- 
nidium (Pl. XV, fig. 2). In some cases there is a considerable por- 
tion of the stroma above the pycnidial cavity (Pl. XIV, fig. 2), or 
the pycnidial cavities may be surrounded by a thick stroma (Pl. 
XIV, fig. 4, and Pl. XV, fig. 1). Sometimes, on the other hand, 
they are large and irregular, with little stroma (PI. XV, fig. 3). 
The. perithecia by no means uniformly arise below the pycnidia, 
but the two often occur side by side in the same stroma (PI. IX, 
fig. 2; Pl. XIV, fig. 3; and Pl. XII). Sometimes, even, the 
perithecia are above the pycnidia (Pl. XIV, fig. 2). There seems 
to be no constant relation either as to the relative number of pyc- 
nidia or of perithecia in a single stroma. Sometimes the pycnidial 
portion is much larger (Pl. IX, fig. 1); sometimes the perithecia 
predominate (Pl. X, fig. 2); and sometimes the two portions are 
practically equal (Pl. XII). 
A like variability apparently occurs in the sequence of the fruit- 
-ing bodies. As the figures show, the pycnidia sometimes develop 
after the perithecia; the reverse order is frequent; while-in several 
sections (Pl. XII, and Pl. XIV, fig. 3) the two types of fruiting 
bodies were side by side and were producing mature spores abun- 
dantly at the same time. Just what factors determine the produc- 
tion of each type of spore or prevent or delay spore production is 
unknown. It seems probable, however, that climatic influences may 
prevent the development of ascospores in many cases. The action 
of climate may be very indirect, however, for no ascospores of any 
species have yet been obtained in artificial cultures, though £'n- 
dothia fluens, E’. fluens mississippiensis, FE’. tropicalis, and E’. para- 
sitica produce pycnospores abundantly on a variety of media. Cer- 
tainly, climatic factors would not account satisfactorily for the fact 
that pycnidia and perithecia are produced at the same time in ad- 
jacent stromata, or even in different parts of the same stroma. 
The size of the perithecia is rather uniform in the various species 
(Pl. X, fig. 3, and Pls. XI and XVI), being about 0.35 mm. in diame- 
ter. They are typically globose to pyriform, but are usually more or 
