Growing on old wood. Æthalium 5–12 mm. in diameter, the width of the tubules varying from 12–25 mic. in the main branches, with broader expansions at the angles, to 6–12 mic. in the more slender final branchlets. This is one of the most common of the Myxomycetes; it grows in all countries, and in this region may be found on old trunks at all seasons of the year.

4. Lycogala flavofuscum, Ehr. Æthalia large, subglobose or somewhat pulvinate, solitary or gregarious, the surface at first silvery-shining, becoming yellow-brown, minutely areolate, irregularly dehiscent. The wall very thick and firm, hard and rigid; the thick outer layer of roundish brown vesicles closely compacted in numerous strata; from the vesicles of the lower strata the long and broad much-branched tubules proceed into the interior among the spores; the ultimate branchlets clavate and obtuse at the apex. Spores in the mass pale ochre, cinerous or brownish, globose, minutely warted, 5–6 mic. in diameter. [See Plate III, Figs. 8, 9.]

Growing on old trunks. Æthalium 1 to several centimeters in diameter, the width of the tubules varying from 25–60 mic. in the main branches, with sometimes much broader expansions at the angles, to 10–25 mic. in the ultimate branchlets. The brown vesicles of the outer wall are easily separated from each other and emptied of their contents by maceration; it is then seen that a thin pellucid membrane incloses numerous roundish granules, much resembling the spores, but usually a little larger, 5–8 mic. in diameter.

Order II.—RETICULARIACEÆ.

Sporangia simple, regular and stipitate, or compound, forming an æthalium; the wall a thin membrane with distinct fibrous thickenings upon the inner surface, the membrane, or at least certain portions of it, disappearing usually at the maturity of the spores, leaving behind the more permanent fibrous thickenings as a more or less definite capillitium. Spores globose, purple, brown, ochraceous, rarely violaceous.

In this order the threads of a capillitium first make their appearance; but they are confined to the inner surface of the wall of the sporangium, being set at liberty by the early decay of the outer membrane.

Table of Genera of Reticulariaceæ.

a. Æthalia.