Frey—Physiology of Yenturia Inequalis. 
327 
dium is formed and abstricted the conidiophore grows further and 
produces another conidium, leaving a shoulder or node where 
the former was cut olf. In culture several shoulders may be 
grouped; apparently the interspaces between the shoulders are 
extremely short, causing the conidia to appear in groups. The 
conidia are two-celled in most cases, each cell being uninucleate. 
The conidia measure about seven to ten microns in diameter and 
twenty-eight to forty microns in length. The color of the conidium 
is olive or brown. 
Perithecial development, as previously stated, begins in autumn. 
The first evidence of perithecia was obtained from leaves fixed 
November 14, 1916, At that time the perithecia were approxi¬ 
mately forty to seventy-five microns in diameter. Sections showed 
that considerable internal differentiation had occurred as each 
perithecium contained several large cells which stained more heav¬ 
ily than the surrounding tissue. The perithecia are spherical in 
form, each consisting of a dense mass of closely interwoven dark 
colored hyphae. The diameter of a mature perithecium varies but 
may exceed 150 microns. The perithecium may be formed in any 
part of the leaf but generally on the side lying uppermost. The 
perithecium is generally embedded in the spongy parenchyma and 
may be seen with the hand lens as it pushes up forming a small 
papilla or dome just before it discharges its spores. The spores 
are discharged through the opening known as the ostiole, but 
when ripe and suddenly wetted the whole upper portion of the 
perithecium may be lifted off. The discharge is produced, so far 
as could be ascertained, by the hydration of a colloidal gelatinous 
mass surrounding the asci which swells enormously. 
The organism was grown in culture and observations were made 
to determine the course of development. Oatmeal agar proved 
to be a satisfactory medium for growth. Potato agar failed to pro¬ 
duce perithecia. It was necessary to keep the cultures in the re¬ 
frigerator to produce perithecia. The observations on the effect 
of temperature were first made by Jones (1913). A tube was inoc¬ 
ulated and allowed to remain at room temperature for several 
weeks and then placed in the refrigerator which was held at a 
temperature of about 8° C. 
Various fixatives were tried but Flemming’s medium proved to 
be the most satisfactory. Urea was added to increase the rate of 
penetration when the perithecia were large and gelatinous. Fixa¬ 
tions were made twice each week. 
