m the _Melanconieae,_ on the fundamental basis that
the former possess a distinct perithecium, while the latter do not.

The _Sphaeropsideae_ as recently defined by Cooke are "Fungi _possessed of
a perithecium, but without asci_, ... sporules or stylospores being
produced internally at the apex of more or less distinct supporting
hyphae or pedicels, termed sporophores."

The Sphaeropsideae somewhat resemble the Pyrenomyceteae in external
characteristics, but differ from them in the absence of asci and
paraphyses. Saccardo retains all the species in his Sylloge, but
relegates them to an inferior position as imperfect fungi.

The group _Pyrenomycetes_, or _Sphaeriacei_, as at first recognized by
_Fries_, included not only the _Sphaeriacei_ and the _Perisporacei_, but
also the _Sphaeropsidei_ and _Melanconiaceae_. Later, when ascigerous
fungi were separated from stylosporous fungi, this group was revised,
the ascigerous species only being retained. As at present limited, the
Pyrenomycetes are "_ascigerous_ fungi having the fructification enclosed
within a perithecium."

They constitute a very large group, the described species, according to
Cooke's Census of Fungi, numbering not less than 10,500, or at least
1,000 more than all the recorded species of Hymenomycetes. The plants
are microscopic in size, and grow upon vegetable or animal substances.

HYPHOMYCETES.

With regard to the Hyphomycetes, Cooke takes the ground that in their
internal relations to each other, and their external relations to the
remaining orders, the Hyphomycetes are undoubtedly a well-defined and
natural group, and should have place as such in a systematic work. It is
a large order, containing nearly 5,000 species, mostly parasitic on dead
animals and vegetable matter. The spores, termed conidia, are free, as
in Hymenomycetes. The species are microscopic in size, and the hyphae are
strongly developed. They have no hymenium and no true basidia, and are
non-sexual in their reproduction.

The four primary sections are the Mucedineae, or "white moulds;" the
Dematieae, or "black moulds;" the Stilbea, with the hyphae or thread-like
filaments pallid or brown, and densely cohering, and the Tubercularieae,
with the hyphae densely compacted in wart-like pustules of somewhat
gelatinous consistency.

The divisions called Melanconieae, Sphaeropsideae, and Hyphomyceteae are not
recognized in the Brefield system of classification as distinct groups.