pigment, oil globules,
and sometimes crystals of calcium oxalate.

~Reproduction.~--Apical spore formation--asexual;
zoospores--sexual.

~Mucorinae.~--_Mucor_ (Fig. 77).--Note the branching filaments--"mycelium"
(a), "hyphae" (b).

Note the asexual reproduction.

1. A filament grows upward. At its apex a septum forms, then a globular
swelling appears--"sporagium" (d). This possesses a definite membrane.

2. From the septum grows a club-shaped mass of protoplasm--"columella"
(c).

[Illustration: FIG. 77.--Mucor mucedo.]

[Illustration: FIG. 78.--Aspergillus]

3. The rest of the contained protoplasm breaks up into "swarm spores"
(e).

Finally the membrane ruptures and spores escape.

~Perisporaceae.~--_Aspergillus_ (Fig. 78).--Note the branching
filaments--"mycelium" (a).

[Illustration: FIG. 79.--Penicillium.]

Note the asexual reproduction.

1. A filament (b) grows upward, its termination becomes clubbed; on
the clubbed extremity flask-shaped cells appear--"sterigmata" (c).

2. At free end of each sterigma is formed an oval body--a spore or
"gonidium" (d), which, when ripe, is thrown off from the sterigma. Two
or more gonidia may be supported upon each sterigma.

_Penicillium_ (Fig. 79).--Note the branching filaments--"mycelium" (a)
(frequently containing globules).

Note the asexual reproduction.

1. A filament grows upward--"goniodophore" (b)--and its apex divides
up into several branches--"basidia" (c).

2. At the apex of each basidium a flask-shaped cell, "sterigma" (d),
appears.

3. At the apex of each sterigma appears a row of oval cells--"spores" or
"conidia" (e). These, when ripe, are cast off from the sterigmata.

[Illustration: FIG. 80.--Oidium.]

~Ascomycetae.~--_Oidium_ (Fig. 80).--(This family is perhaps as nearly
related to the blastomycetes as it is to the hyphomycetes.)

Note the branching filaments--"pseudomycelium" (a). Here and there
filaments are broken up at their ends into oval or rod-shaped segments,
"oidia," and behave as spores.

Note the asexual reproduction. From the pseudomycelium arise true hyphae
(b), each of which in turn ends in a chain of spores (c).

~MORPHOLOGY OF THE BLASTOMYCETES.~

The blastomycetes are composed of spherical or oval cells (8 to 9.5 mu in
diameter), which, when rapidly multiplying by budding, may form a
spurious mycelium. A thin cell-wall encloses the granular protoplasm, in
which vacuoles and someti