are in _Brefeldia_ pretty well defined.

1. BREFELDIA MAXIMA (_Fr._) _Rost._

PLATE V., Figs. 7, 7 _a_, 7 _b_, and PLATES XXI., XXII.

1825. _Reticularia maxima_ Fries, _Syst. Orb. Veg._, I., p. 147.
1875. _Brefeldia maxima_ (Fr.) Rost., _Versuch._, p. 8.

Aethalium large, four to twenty cm, papillate above, violet-black at
first, then purple or purple-brown, developed upon a widespread,
silver-shining hypothallus; sporangia in favorable cases distinct,
indicated above by the papillae; columellae obscure, black; capillitium
abundant, the threads uniting by multifid ends to surround as with a net
the peculiar vesicles; spore-mass dark violet-black, the individual
spores paler by transmitted light, distinctly papillose, 12-15 mu.

A very remarkable species and one of the largest, rivalled by _Fuligo_
only. To be compared with _Reticularia_, which it resembles somewhat
externally, and with some of the larger specimens of _Enteridium_. The
plasmodium at first white with a bluish tinge is developed abundantly in
rotten wood, preferably a large oak stump, and changes color as maturity
comes on, much in the fashion of _Stemonitis splendens_, leaving a
widespread hypothallic film to extend far around the perfected
fruit-mass. In well-matured aethalia, "_Jove favente_," the sporangia
stand out perfectly distinct, particularly above and around the margins.
Closely and compactly crowded, they become prismatic by mutual pressure,
and attain sometimes the height of half an inch or more. In the centre
of the fructification, next the hypothallus, the sporangia are very
imperfectly differentiated. Many are here horizontally placed, and
perhaps supplied with an imperfectly formed peridium,--if so are to be
interpreted the lowest parts of the capillitial structure, the long,
branching, ribbon-like strands which lie along the hypothallus. Some of
these branch repeatedly with flat anastomosing branchlets, ultimately
fray out into lengthened threads, and perish after all the
superstructure has been blown away. From every part of the structure so
described, but more especially from the margins, are given off in
profusion the strange cystiferous threads, so characteristic of this
genus. These are exceeding delicate filaments, attached at one end, it
may be, to a principal branch, at the other free or united to a second
which again joins a third, and so looping and branching, dividing, they
form a more or less extended network, a ca