almost
black

_Cribraria dictydioides_ clear dark green

_Cribraria tenella_ watery, dark plumbeous, bronze

_Cribraria cuprea_ red

_Arcyria nutans_ white

_Arcyria denudata_ watery white, then flesh-color

_Arcyria cinerea_ grey, then white

_Trichia varia_ colorless, then white

h. In a few instances references to illustration do not find place in
connection with the descriptive matter. One phase of _Physarum
albescens_ is figured on Pl. III.; _Mucilago_ will be found portrayed on
Pl. VII.; _Physarum viride_ on Pl. VIII.

j. The group before us has research possibilities not a few. The
question of their nutrition and its limits in respect of variety, is yet
to be solved. From present indications all that can be said is to the
effect that a pabulum similar in variety, no doubt meets the needs of
many species. Whether in artificial culture a single base as gelatin or
agar would suffice for all or several is yet to be discovered.

Whether a species brought from spore to maturity on artificial diet
would conform in any reasonable way to our dim concept of its identity
is also, it would seem, a problem. The variation in the field would seem
to make it doubtful.

From the table immediately preceding it is plain that there is place for
doubt. Color it is surmised is of itself everywhere incidental; the
structure, which maintains identity or the reverse, lies deeper,
although color may be none the less, in some way a resultant, and
therefore in so far a reliable taxonomic guide.

The treatment of our subject so far by no means exhausts the
possibilities of even the simpler phases of microscopic study. We have
endeavored to appreciate the work of those who hand us the literature of
the group, and to recognize what such keen-eyed men have seen; but in
our western and southern forests there are probably double as many
species, as species go, as we have listed.

The entire group is, as it would seem, in highest measure worthy of
investigation and comprehension, and should it at any time prove that to
such accomplishment the present volume may have been in any smallest way
contributory, the author's satisfaction will be complete indeed.

FOOTNOTES:

[40] Farr. _Cell-division in Pol. Mother-cells, Cobaea scandens, Bull.
Tor. Bot. Cl._, Vol. 47, pp. 325-38.

INDEX

NATURAL ORDERS