3b. Acaulon muticum var. rufescens (A. Jaeger) H. A. Crum, Bryologist. 72: 240. 1969.
Acaulon rufescens A. Jaeger, Ber. Thätigk. St. Gallischen Naturwiss. Ges. 1868-1869: 77. 1869
Plants yellow- to red-brown in nature. Spores variably low papillose-punctulose or smooth.
Capsules mature late fall to early spring. Soil, gravel pit, pasture, lawn; low to moderate elevations; B.C., Ont., Que., Sask.; Ariz., Calif., Fla., Ill., La., Md., Mich., Miss., Mo., Nebr., N.J., N.Y., Okla., Oreg., S.C., Tex., Wis.; Mexico.
A specimen of var. rufescens from New Jersey (Austin 51, UBC) is reddish and has small (ca. 20 µm), round, weakly papillose spores; generally, spore size is not a good character. Another specimen, with large (38-40 µm), round, punctulate spores, is piebald with adherent granules similar to the papillae of var. muticum. One specimen placed here (California, Santa Clara County, Stanford University, W. Schofield 5724, Feb. 23, 1955, UBC), is rather immature, has a greenish cast and smooth, elliptic spores about 28-30 µm.