Maine to the Black Hills and Colorado, and north and west; Alaska to Nicaragua.

9. Arcyria cinerea (Bull.) Pers.

[Plate II.], Figs. 3, 3 a.

Sporangia scattered or gregarious, ovoid or cylindrical, generally tapering upward, about 2–3 mm. high, ashen gray, sometimes with a yellowish tinge, stipitate; calyculus very small, thin; stipe about half the total height, rising from a small hypothallus, thin, gray or blackish, densely crowded with spore-like cells; capillitium dense, freely branching, ashen, or yellowish, little wider below, minutely spinulose; spore-mass concolorous, spores by transmitted light colorless, smooth, 6–7 µ.

A very common little species, easily recognized by its color and habit. The capillitium is more dense than in any other species and expands less. The stipe is about equal to the expanded capillitium, unusually long. The plasmodium occurs in rotten wood, especially species of Tilia, is gray and, judging from the number of sporangia found in one place, scanty.

Bulliard, l. c., gives the first account of the species by which it can with any certainty be identified. By some authors Clathrus recutitus Linn. is cited as a synonym. We fail to distinguish A. cookei Mass. from the old type.

Widely distributed; Maine to Alaska, and south to Mexico and Nicaragua.

10. Arcyria digitata (Schw.) Rost.