290 Wisconsin Academy of Sciences^ Arts, and Letters. 
scopic characters while similar macroscopically. In the former the 
sporules are borne in pycnidia, are obtuse, continuous 40-55x about 
4:11. In the latter they are borne in acervuli, are acute, 1-septate, 
17-33x2-3/a. Examination of specimens, however, shows that the 
matter is not as simple as it appears. To illustrate I give some 
notes of various specimens. 
On Fraxinus pennsylvanica lanceolata. 
7-22-21. Pycnidia distally imperfect (hemispherical); sporules 
subacute to obtuse, becoming 1-septate, 27x50x3ju. 
7-21-22. Pycnidia more or less imperfect; sporules continuous, 
40—60x3/x. 
7-7-20. Distal portion of pycnidia imperfect; sporules obtuse or 
acute at one end, continuous, 30-50x2%-4/a. 
On Fraxinus nigra. 
7-29-20. Pycnidia more or less imperfect; sporules acute, con¬ 
tinuous, 27-33x3jLt. 
7- 1-18. Pycnidia distally imperfect'; sporules acute, continuous, 
23-32x2jLt. 
9-3-15. Pycnidia distally imperfect; sporules acute, continuous, 
23—33x3jLi. 
8- 10-15. Spore bodies ranging from prominent acervuli to innate 
pycnidia; sporules acute, continuous, 24-36x2-3jLi. 
Fungi Columhiani 1526 on Fraxinus pennsylvanica lanceolata 
from Kansas, issued as Cylindrosporium fraxini E. &. K., bears 
sporules which are obtuse, tapering toward one end, becoming 
1-septate 33-45x3jii and apparently belongs in this duplex. The 
character of the spore body in such groups as this appears to de¬ 
pend upon its position in the leaf. The beginning of a spore body 
is a spherical mass of hyphae in the leaf tissue. A wall develops 
on the periphery of the hyphal mass and under this protection a 
sporuligerous or hymenial layer is developed on the inner surface 
of the wall which gives rise to the reproductive bodies. Normally 
the pycnidium is globular and the entire inner surface of the wall 
is lined with hymenium except a small opening for the discharge 
of the sporules, the ostiole. When, however, the primary hyphal 
mass is in contact with the epidermis or by destruction of interven¬ 
ing host tissue becomes pressed against it no wall or hymenium is 
formed by the portion in contact with the epidermis. This results 
in a pycnidium the distal portion of which is defective. If the 
