Sporangia crowded, cylindric, about 2 mm. high when unexpanded, pale yellow or buff, short-stipitate or sessile by an acute base; peridium wholly evanescent, except at the base, where persists the shallow, colorless, often inwardly spinulose, plicatulate calyculus; stipe very short or wanting; hypothallus thin but usually in evidence; capillitium expanding to great length, forming an extremely flexile, plumose, pendulose open network of pale ochraceous tint, the threads 3–4 µ in thickness, adorned with spinules, sharp edged transverse plates sometimes rings, the surface especially marked by an indistinct reticulation; spore-mass buff or ochraceous, spores by transmitted light colorless, smooth or nearly so, 7–8 µ.

This elegant species is not rare in undisturbed woods, especially on fallen willows. The expanded capillitia are very soft and plume-like, waving and nodding, very lightly attached below to the centre of the peridial cup. The capillitium threads are rough, with irregular spines and sharp-edged transverse plates, occasionally extending to form rings. Resembles the first species somewhat in habit, size, and the spinescent capillitium, but the resemblance is superficial only. The color is at once diagnostic, and the capillitium is after all entirely different. Not uncommon; Canada to Mexico; Maine to California; probably cosmopolitan.

Bulliard's figure determines the synonymy. Persoon called the form A. flava, because Bulliard had missed the genus.

4. Arcyria versicolor Phillips.

Sporangia gregarious or more or less crowded, pyriform or clavate, dingy, olivaceous yellow, becoming reddish, stipitate; peridium membranous, largely persistent below, where it gives rise to the deep, goblet-shaped calyculus; stipe strand-like, weak, sometimes wanting, concolorous with the peridium; hypothallus prominent or venulose; capillitium only slowly expanded, bright golden yellow or orange, the threads rather broad, about 4 µ in diameter, regular, even, elegantly branching, adorned with abundant short spines or warts, very small and evenly distributed, the whole net anchored in the bottom of the vasiform calyculus; spore-mass yellow, by transmitted light pale or nearly colorless, smooth, about 10 µ.

This beautiful species is easily known by its comparatively large size, peculiar, obovate shape, its brilliant color, and unusually persistent membranous calyculus. It is peculiar to the western part of North America, South Dakota west to the Pacific Ocean.

South Dakota, Colorado, California, Washington.

In the thin-covered mountains of Colorado, or hidden by the still drier thickets and woods of Southern California, the fruit of this species is small, somewhat as the clavate hemitrichia, pure, deep yellow, golden or vitelline as Phillips says; but at loftier altitudes in the ever cool forests on the high mountain flanks, beginning away up where the glacier first starts to crack and slide between the 'cleavers', and forests of stunted white-stemmed pine or wooly-fruited fir throw down their twigs and foliage undisturbed through centuries,—on down to where the plowing ice forgets its thrust, and melts to gentle floods amid spruce and hemlock-groves,—all the way the beautiful versicolor spreads and fruits, in August and September in all the richness of color which its name implies, which Phillips saw, tints of red, and yellow, and olive, and green, not brilliant, but in all the softer shades the artists love, weaving, in far-spread strands of tufted cylinders and cones upturned, fair as flowers, dusky garlands, by sunlight long forgot! Did not the old-time botanists liken these things once and again, to flowers!

5. Arcyria incarnata Persoon.