The fruit-bodies before they are ripe are spherical or ovoid, and
enclosed by a _fleshy covering_, the peridium, which is _perforated
at maturity_ and remains as a sheath (Fig. 179); the fruit-bodies are
_hemiangiocarpic_.
Order 1. =Phallaceæ= (=Stink-horns=). The peridium has a complicated
structure and is composed of three layers, the intermediate one being
thick and gelatinous. The gleba (the tissue which bears the hymenium)
is situated upon a peculiar receptacle which expands into a porous
stalk and by its sudden distension, rupturing the peridium, elevates
the gleba and hymenium above the peridium, which remains as a sheath.
_The gleba becomes gelatinous and dissolves away as drops._ To this
order belong many peculiar and often brightly coloured forms, which are
natives of the Southern Hemisphere.
_Phallus impudicus_ (Stink-horn) (Fig. 179), has a fruit-body
which at first is white, heavy, and soft, and resembles a hen’s
egg in shape and size. The peridium is divided into three layers
(Fig. 179 _e_, _g_, _f_) of which the external and internal
are membranous, and the middle one very thick and gelatinous;
each of these has again a laminated structure. The peridium
when ruptured remains as a sheath (_k_) at the base of the
stalk. The receptacle at first is strongly compressed (_h_)
but afterwards expands into a long stalk (_l_) which bears the
conical gleba (_m_). Prior to the rupture of the peridium the
gleba consists of a greenish mass (_i_) which, when exposed,
emits a carrion-like stench serving to attract flies, by whose
agency the spores are distributed. It is found commonly in
hedgerows and in woods, growing on the ground. The much smaller
and less common _P. caninus_ is found on rotten tree-stumps.--In
_Clathrus cancellatus_ the receptacle expands into a bright red,
reticulate structure. A native of the South of Europe. _Colus_,
_Aseroë_, _Mitromyces_.
Order 2. =Sphærobolaceæ.= An intermediate layer of the
_peridium_ swells when ripe, becomes convex, and _ejects the
remaining_ spherical _portion of the fruit-body_ which contains
the spores. _Sphærobolus carpobolus_ has small, spherical
fruit-bodies which open in the form of a star.
[Illustration: FIG. 179.--_Phallus impudicus_ (Stink-horn),
somewhat diminished. Fruit-bodies in all stages of development
(_b_, _c_, _d_ and _k-m_) are seen arising from a root-like
mycelium (_a_); _d_ longitudinal sections through a fruit-body
before the covering has ruptured.]