iculate threads surrounding the spores. Schrader redefined
the genus; opposed Persoon's view as to the capillitial nature of the
net, and separated the genus _Dictydium_, but by imperfect
limitations,--in fact, chiefly because of the more completely evanescent
peridium. Fries follows Schrader. Rostafinski first clearly separated
the two genera, and his classification is here adopted. Nevertheless,
after reviewing the subject entire one is more and more inclined to
appreciate the commendation of Fries; "Auctor Schrader, qui insuper
plurimas species detexit, et hoc et sequens genus ita proposuit ut
sequentes vix aliquid addere valuerint."

As to the habitat of the cribrarias, the remark of Schrader is still
pertinent--"in vetustissimis plenariae destructionis proximis arborum
truncis"--for all the species. Rotten, coniferous wood seems to be
preferred, but the decayed logs of trees of other orders are by no means
refused. Rotten oak forms a very common habitat.

=Key to the Species of Cribraria=

_A._ Sporangia with spores ochraceous or brownish.

_a._ Sporangia larger, .5 mm. or more.

1. Net poorly developed, sometimes merely
indicated 1. _C. argillacea_

2. Net conspicuous, nodes expanded, not swollen.

i. Calyculus reticulately thickened,
ill-defined above 2. _C. macrocarpa_

ii. Calyculus with radiant lines or ribs;
net small-meshed; free ends none 6. _C. aurantiaca_

iii. Net wide-meshed, calyx rufous 4. _C. rufa_

iv. Calyx replaced by ribs 5. _C. splendens_

3. Net conspicuous, nodules swollen.

i. Net-threads simple; free ends many 7. _C. dictydioides_

ii. Net-threads often parallel in twos
or threes 8. _C. intricata_

_b._ Sporangia small, less than .5 mm.

1. Nodes not expanded 3. _C. minutissima_

2. Nodes well shown.

i. Calyculus distinctly marked by
radiant lines, nodes round 10. _C. tenella_

ii. Calyculus minute or none;
nodes prominent 11. _C. microcarpa_

_B._ Sporangia more or less marked with purple or violet tints.

_a._ Purple or violet throughout.