PLATE 7 1 * 
A-D.—Stages in the development of the branches which start from the substomatal 
mycelium, push through the stomatal pore, and by forming lobed outgrowths give 
rise to the crowded group of knoblike buds that develop into the conidiophores. 
Maize (Guam White Flint) infected by Sclerospora spontanea; exterior view of the 
epidermis showing stages characteristically found from io to n p.m. A.—Stomata 
not yet invaded; its pores closed to a narrow slit. B.—From the substomatal mycelium, 
part of which can be seen dimly beneath the epidermis at a and 6, many knoblike 
branch tips are crowding up through the stomatal pore. C.—A later stage in the 
growth of the knoblike branches, some of which have enlarged and pushed still farther 
out of the stoma. D.—A still later stage; the knoblike branches have grown into 
enlarged and lobed outgrowths which will elongate into the club-shaped conidiophore 
initials. X700. 
E. —A similar stoma seen in longitudinal section at a later stage in the development 
of the conidiophores. Above the group at a is shown the base of a conidiophore that 
has already 4 lost its conidia and begun to shrink. At b is the base of another which is 
just maturing. Below are several knoblike outgrowths that will develop into conidio¬ 
phores in their turn. From a longitudinal section of the same material cut at 2.30 a.m. 
X 7 °°* 
F. —A group consisting of outgrowths and their maturing conidiophores. Similar 
to that shown in E but dissected out from the surrounding tissue. The maturing 
conidiophore whose base is shown at a is figured in full in Plate 8, Q. 2.30 a.m. X700. 
G. —Portion of a cross section of the same material, showing in the substomatal 
chamber vigorous mycelial branches from which has arisen a group of knoblike out¬ 
growths. At a is the basal extremity of a conidiophore already matured. 2.30 a.m. 
X700. 
H. —Portion of a cross section of Saccharum sponatneum leaf heavily infected with 
Sclerospora spontanea. From the stoma, which, in this grass, is deeply depressed and 
protected by ridges, has pushed out a small group of outgrowths one of which has 
begun to elongate into a conidiophore. Their relationship to the vigorous mycelial 
branches in the substomatal chamber can be traced clearly. 2 a.m. X700. 
1 The drawings were made with the aid of a camera lucida and are from living material hand sectioned at 
night in water, the sections being immediately killed and fixed in osmic acid, stained, and mounted. 
