106 N. C. AGRICULTURAL EXPERIMENT STATION. 
the ascophore. From 3 to 35 ascophores were produced from each 
sclerotium. 
The Ascophore .—The Ascophore may he regarded as composed of 
two portions, the stalk or stipe, and the disk, though no sharp line of 
demarkation can he drawn between these parts. As many as thirty- 
five stipes have been noted from a single sclerotium, but usually there 
are not more than eight or ten. There are no particular points upon 
the sclerotium from which they arise, hut in case the sclerotium lies 
upon the surface of the ground, they usually spring from the sides of 
it nearest to the soil. Their length depends upon the depth of the 
sclerotium in the soil. If the sclerotium is upon the soil surface, the 
stipe is just long enough to allow the disk to expand. When the 
sclerotium is buried the stipe becomes a sufficient length to reach) 
the surface, sometimes attaining a length of 3 to 5 cm. In thickness 
the stipes vary from about 0.5 to 1.2 mm. The color of the shorter 
stipes is almost universally brownish yellow, but the longer ones while 
brownish yellow just below the disk are dark brown to almost black 
at the sclerotial end. 
In cross section the stipe is seen to be hollow and to possess an 
outer cortical region composed of two or three irregular layers of 
black thick-walled cells, encasing a tissue of parenchymatous appear¬ 
ance. In longitudinal section, cells of the outer cortical layers appear 
about three times as long as wide, while the rest of the tissue appears 
as a mass of ordinary mycelial threads with rather more than the 
usual number of septa. 
The disk is borne upon the end of the stipe. It is at first very 
small and deeply cup shaped. This cup gradually expands at the rate 
of one-half to 1 mm. per day and forms the flat or concave circular 
disk, which sometimes attains a diameter of 16 mm. It is composed 
of two distinct parts, the stro?na and the hymenium. The stroma 
or basal part consists of a mass of closely interwoven hyphse with an 
outer cortical parenchymatous layer two or three cells thick which 
forms the under surface of the disk. The stroma supports the hy¬ 
menium composed of asci (Fig. 6) and sterile hyphse lying between 
them, the paraphyses (Fig. 6). The asci are cylindrical with a grad¬ 
ually narrowing base. They measure about 82 x 2 mu and bear 8 
spores in their distal half. The asci are very numerous, there being 
about 30,000 in a single disk of usual size. Between the asci and 
more numerous than the asci are the very fine thread-like paraphyses 
which are slightly longer than the asci, and not more than one-third 
as thick. The paraphyses do not differ materially from the ordinary 
hyphse of the mycellium. 
The spores found in the asci are hyaline, oblong, elliptical with 
somewhat pointed ends, and when mature bear two vacuoles. They 
measure 5.8 x 8.7-11.6 mu. 
In a single disk there are about thirty-one million spores; in a sin¬ 
gle sclerotium of average size about three hundred and ten million 
spores. Allowing a fair number of sclerotia to each diseased lettuce 
plant it is seen that it can produce as many as five billion spores. 
