6 
Mas see. — A Monograph of 
hymenial surface in the present group than in the Hymeno- 
mycetes, in fact, so far as relates to the earliest condition, it 
may be said that there is but one plan. The first sign of dif- 
ferentiation observable in the young gleba is the appearance 
of numerous minute rifts in the hitherto homogeneous weft of 
hyphae. These rifts increase in size with the growth of the 
sporophore, and eventually form a complicated labyrinth of 
sinuous cavities. The walls separating the cavities consist of 
branched septate hyphae which in the middle portion usually 
run more or less parallel to the surface of the walls and con- 
stitute the trama. The free surfaces of the walls enclosing the 
cavities become converted into the hymenial layer, the basidia 
being terminal branches of the hyphae of the trama (Fig. 54). 
The walls of the gleba are at first always continuous with the 
inner surface of the peridium, and in the Hymenogastreae and 
the Sclerodermeae are persistent, as they are also to some 
extent in the Nidularieae, whereas in the Lycoperdeae and 
the Phalloideae, the whole of the trama and hymenial layer 
disappear after the formation of the spores. Further details 
relating to the structure of the gleba will be given under the 
respective orders. The basidia are much more variable in 
form, and the number of spores by no means so constant as in 
the allied Hymenomycetes. In the Hymenogastreae the num- 
ber of spores borne on a basidium varies from one to four, two 
being the most usual number, and it is by no means unusual 
to meet with bisporous and tetrasporous basidia in the same 
hymenium. In the Phalloideae the very minute spores vary 
from four to eight on different basidia. According to De Bary 1 
the large clavate basidia of Geaster hygrometricus produce 
eight sessile spores. In the genera Bovista and Lycoperdon 
the basidia are tetrasporous, the spores being supported 
on very long sterigmata, which in most species break off close 
to the basidium and remain permanently attached to the 
spores, which explains the term ‘ spores stipitate,’ sometimes 
used by systematists (Fig. 62). In all the examples hitherto 
1 1. c. p. 63-. 
