Fig. 233.
Agaricus campestris.
Longitudinal section through stem and pileus.
a, pileus; b, portion of veil on margin of pileus;
c, gill; d, fragment of annulus; e, stipe.
Fig. 234.
Portion of section of lamella of Agaricus campestris.
tr, trama; sh, subhymenium; b, basidium;
st, sterigma (pl. sterigmata); g, basidiospore.
Fig. 235.
Portion of hymenium
of Coprinus micaceus,
showing large cystidium
in the hymenium.
421. Fruiting surface of the mushroom.—The surface of these gills is the fruiting surface of the mushroom, and bears the gonidia of the mushroom, which are dark purplish brown when mature, and thus the gills when old are dark in color. If we make a thin section across a few of the gills, we see that each side of the gill is covered with closely crowded club-shaped bodies, each one of which is a basidium. In [fig. 234] a few of these are enlarged, so that the structure of the gill can be seen. Each basidium of the common mushroom has two spinous processes at the free end. Each one is a sterig′ma (plural sterig′mata), and bears a gonidium. In a majority of the members of the mushroom family each basidium bears four spores. When mature these spores easily fall away, and a mass of them gives a purplish-black color to objects on which they fall, so that a print of the under surface of the cap showing the arrangement of the gills can be obtained by cutting off the stem, and placing the pileus on white paper for a time.
Fig. 236.
Agaricus campestris.
Soil washed from “spawn” and “buttons,” showing the minute
young “buttons” attached to the strands of mycelium.