Persoon changed Bulliard's specific name in this case to furnish one himself, more descriptive as he thought and distinctive. His success in this attempt must be esteemed but partial since all the related forms, immediately listed, _nod_ as well. Bulliard's name as applied by Persoon is therefore to be preferred. But the transfer from _Tilmadoche_ to _Physarum_ loses for us one step in the ladder of priority. _P. album_ (Bull.) may not enter here, since Fries has given us one species under that title. So Persoon comes next on the list, all the world now nodding approbation, let us hope! Under the name _Physarum gracilentum_, Fries cites an extremely delicate form of this species. The sporangia are of the most minute, about .2-.3 mm. in diameter, globose, slightly umbilicate below, the stipe usually white at top, but sometimes black throughout. This graceful form occurs rarely in undisturbed woods. Widely distributed in the eastern United States, apparently rare in the west. Reported from various parts of the world; Europe, Japan, Australia, etc. 56. PHYSARUM VIRIDE (_Bull._) _Pers._ PLATE VIII, Figs. 8, 8 _a_, 8 _b_. 1791. _Sphaerocarpus viridis_ Bull., _Champ._, t. 407, Fig. I. 1791. _Sphaerocarpus luteus_ Bull., _Champ._, t. 407, Fig. II. 1791. _Sphaerocarpus aurantius_ Bull., _Champ._, t. 484, Fig. II. 1791. _Stemonitis viridis_ (Bull.) Gmel., _Sys. Nat._, p. 1469. 1794. _Physarum aureum_ Pers., Roemer, _Neu. Mag. f. die Bot._, I., p. 88. 1795. _Physarum viride_ Pers., Usteri, _Ann. Bot._, XV., p. 6. 1801. _Physarum aurantium_ Pers., _Syn. Meth._, p. 173. 1829. _Physarum nutans_ var. Fries, _Syst. Myc._, III., pp. 128-129. 1875. _Tilmadoche mutabilis_ Rost., _Mon._, p. 129. 1880. _Tilmadoche viridis_ (Bull.) Sacc., _Michelia_, II., p. 263. 1894. _Physarum viride_ Pers., List., _Mycetozoa_, p. 50. 1899. _Tilmadoche viridis_ (Bull.) Sacc., Macbr., _N. A. S._, p. 59. 1911. _Physarum viride_ Pers., List., _Mycetozoa_, 2nd ed. Sporangia globose, flattened or lenticular, beneath plane or concave, variously colored, yellow, greenish yellow, rusty orange, stipitate, nodding; the peridium splitting irregularly or reticulately; stipe variable in length and color, through various shades of red and yellow, subulate; capillitium strongly developed, concolorous with sporangium, the tubes with colorless or yellow calcareous thickenings; spores smooth, fuscous or violet-black, 8 mu. A very handsome and rather common little species; like the preceding, but generally greenish-yellow in color, and occasionally brilliantly orange without a suggestion of green. Indeed, the color is so variable that some authors have been disposed to discard the species entirely, inasmuch as the chief specific character is color. The plasmodium is pale yellow, in rotten logs, stumps, etc. In the paler yellow or greenish forms the stipe is more commonly black.