ies. Found from September to October.

_Bovista. Dill._

The genus Bovista differs from Lycoperdon in several ways. When the
Bovista ripens it breaks from its moorings and is blown about by the
wind. It opens by an apical mouth, as does the genus Lycoperdon, but the
species of Bovista have no sterile base. They are puffballs of small
size. The outer coat is thin and fragile and at maturity peels off,
leaving an inner coat firm, papery, and elastic, just such a coat as is
suitable for the dispersion of its spores. Leaving its moorings at
maturity, it is blown about the fields and woods, and with every tumble
it makes it scatters some of its spores. It may take years to accomplish
this perfectly. The species of the Lycoperdon do not leave their
moorings naturally; their spores are dispersed through an apical mouth
by a collapse of the walls of the peridium, after the fashion of a
bellows, by which spores are driven out to the pleasure of the wind. In
Bovista the threads are free or separate from the peridium, but in
Lycoperdon they arise from the peridium and also from the columella.

_Bovista pila. B. & C._

THE BALL-LIKE BOVISTA.

[Illustration: _Photo by C. G. Lloyd._

Plate LXIII. Figure 471.--Bovista pila.

Natural size of matured specimens.]

Pila means a round ball. The peridium is globe-like, sessile, with a
stout mycelium, a cortex thin, white at first, then brown, forming a
smooth continuous coat, breaking up at maturity and rapidly
disappearing.

The inner peridium is tough, parchment-like, elastic, smooth,
persistent, purplish-brown, fading to gray. The dispersion of spores
takes place through an apical mouth. The capillitium is firm, compact,
persistent, at first clay-colored, then purple-brown; threads
small-branched, the ends being rigid, straight, pointed. There is
something so noticeable about this little tumbler that you will know it
when you see it, and if you often ramble over the fields you will soon
meet it. However, I have as yet seen only the matured specimens.

_Bovista plumbea. Pers._

LEAD-COLORED BOVISTA. EDIBLE.

[Illustration: Figure 472.--Bovista plumbea. Natural size. White when
young.]

The plant is small, never growing to more than an inch and a fourth in
diameter. The peridium is depressed globose, with a fibrous mycelium.
The outer peridium is rather thick and when the plant is nearing
maturity it breaks up readily unless handled very carefully; at maturity
it sc