The Perisporiaceae are saprophytic forms, the two chief genera being
_Aspergillus_ and _Penicillium_. The blue-green mould _P. crustaceum_
and the green mould _A. herbariorium_ ( = _Eurotium herbariorum_) are
extraordinarily widely distributed, moulds being found on almost any
food-material which is exposed to the air. They have characteristic
conidiophores bearing numerous conidia, and also cleistothecia which
are spherical in form and yellowish in colour. The latter arise from
the crown of a spirally coiled archicarp (bearing an ascogonium at its
end) and a straight antheridium. Vegetative hyphae then grow up and
surround these and enclose them in a continuous sheath of plectenchyma
(fig. 11). It has lately been shown by Fraser and Chambers that in
_Eurotium_ both ascogonium and antheridium contain a number of nuclei
(i.e. are coenogametes), but that the antheridium disorganizes without
passing its contents into the ascogonium. There is apparently a
reduced sexual process by the fusion of the ascogonial (female) nuclei
in pairs. _Aspergillus Oryzae_ plays an important part in
saccharifying the starch of rice, maize, &c., by means of the abundant
diastase it secretes, and, in symbiosis with a yeast which ferments
the sugar formed, has long been used by the Japanese for the
preparation of the alcoholic liquor sake. The process has now been
successfully introduced into European commerce.
[Illustration: From Strasburger's _Lehrbuch der Botanik_, by
permission of Gustav Fischer.