526. Z. julacea, Schimp.

Plagiobryum Zierii, (Dicks.) Lindb.

A few sterile specimens collected on earth in crevices of rock about 1000 feet above Lake Lindeman, Yukon. (Williams?)

1089. Z. argenteoides, (Williams.)

Plagiobryum argenteoides, R. S. Williams; Bull. New York, Bot. Gar. Vol. II., p. 129.

With the appearance of Bryum argenteum. In dense tufts up to 1 cm. high. Stems simple or branching, vineous red, radiculose below, in cross-section showing an outer wall of one layer of irregular, somewhat thick-walled cells, with ground tissue of very large, thin-walled cells, becoming smaller toward center and enclosing a distinct central strand. Leaves concave, appressed, broadly ovate, with short abrupt point, entire, mostly 1/2 mm. long or less or occasionally the terminal leaves lanceolate pointed and up to 1 mm. long. Costa vanishing from 1/3 to 2/3 up. Upper 1/3 of leaf usually hyaline. Alar cells and most basal cells square (sides 12 to 16 mm.) to short rectangular (1 to 2.) Median cells irregularly rhomboidal to oblong-linear, up to .040 or .050 mm. Cell walls somewhat thickened, especially above.

Found on bare rock in dry places on the Yukon River, just below Dawson, Yukon, March 19th, 1899. (Williams)