308 DIVISION II.—COURSE OF DEVELOPMENT OF FUNGI. 
GASTROMYCETES. 
Section LXXXIX. The Gastromycetes include the chief groups of the Hyme- 
nogastreae, Lycoperdaceae, Nidularieae, and Phalloideae; to these are joined 
a few smaller divisions composed partly of forms intermediate between them and partly 
of divergent genera and some small groups. 
The compound sporophores in these Fungi spring from a simple filamentous or 
from a compound mycelium (see page 22). They are for the most part large, often 
very large, bodies; Fig. 141 represents a beautifully small specimen of a small species. 
When forming their spores they are all, with the exception of Gautieria, a genus of 
the Hymenogastreae, receptacles or sacs entirely surrounded by a closed wall of 
dense texture, the deridium or uterus, and usually divided inside by plates of tissue 
springing from the peridium into chambers 
in which the hymenium and the spores are 
formed. 
Gautieria has no peridium ; the chambers 
in the periphery lie on the free surface and are 
open to the outside. In all other forms the 
peridium varies in thickness according to the 
species and is often extremely thick; in many 
cases it is largely and peculiarly differentiated, 
partly into persistent, partly into temporary 
parts, as will be set out at greater length 
presently. It is a general occurrence in the 
course of this differentiation that the peridium 
becomes strongly, often very strongly, thick- 
ened at the base, though there are exceptions 
to this rule, as in Hysterangium and the 
Fic. 141. Octavianta asterosperma, Vittad. Median Nidularieae. The thickened portion either 
SEL, EGR ee Meee sca, © projects oulwards in the form of a ‘stipe 
which bears the chambered portion, as in 
Lycoperdon and Octaviania, Fig. 141; or it projects inwards forming a cushion, as 
in Hymenogaster, Rhizopogon, Geaster hygrometricus (Fig. 146), or as an elongated 
vertical central column, as in most species of Geaster (Vittadini), the Phalloideae 
(see pages 316, 322) and others. The point of origin of the central column is termed 
the base, because in all cases in which the earliest states are known it corresponds 
to the point where the compound sporophore springs from the mycelium, and 
generally also to the place of insertion of the full-grown peridium. In some forms, 
as Rhizopogon and Geaster, mycelial strands run into the peridium at very various 
and often at many points in the outer surface, and the first commencements are 
not known; here therefore the expression base is only applicable by analogy. 
Except in the Nidularieae and some divergent genera which will be specially 
considered at a future time, the chambers inclosed by the peridium are narrow 
irregularly curved and branched cavities, just large enough or too small to be seen 
with the naked eye, and separated from one another by thin curved plates of tissue 

