_Peltigera_ furnishes seven species for Ohio, while only one species of
_Nephroma_ has thus far been found in the State.

The algal hosts are usually _Dactylococcus_ or _Polycoccus_, and both
hosts are sometimes found in the same thallus. The chains of cells are
usually badly broken up, and the nature of the algal host is, therefore,
difficult to distinguish. Other algae doubtless sometimes occur in the
thalli of _Peltigerae_.

_Nephroma_ with cortex on both sides, is to be regarded higher than
_Peltigera_, which has the cortex on the upper side only. The family is
most closely related to the _Stictaceae_, from which family it is kept
distinct on account of the absence of cyphellae and the difference in
disposition of the apothecia.

The collecting on which this paper is based was partly by Bruce Fink in
connection with general collecting of fungi in Butler County and in
collecting in Adams, Warren, Fairfield, Preble, Ross, Highland, and Lake
counties for the Ohio Biological Survey. However, a considerable amount
of material found by other collectors and previously reported from Ohio
was examined. Hence, the collecting for the Ohio Biological Survey added
little to knowledge of the _Peltigeraceae_ of Ohio, except in way of
addition to distribution in the State.

[Footnote B: Contributions from the Botanical Laboratory of Miami
University--XIX]