Mnium Hornum MossMnium hornum, Linn.
Habit and habitat.-Robust in dense tufts, on damp earth in woods, about the roots of trees, and on rocks.
Name.--The specific name, hornum, probably refers to the horny border.
Plant (gametophyte).-The young plants are bright-green, the older are dark-green; steins, 1 to 2 inches high, simple erect; sterile shoots, erect from the base.
Leaves.-The lowest minute, the upper gradually increasing in size, the terminal forming a rosette, all oblong-lance-shaped, apex more or less acute with a sharp little point; base growing slightly down the stern; margin with a strong red border, spiny toothed from below the middle, the teeth in a double row; vein vanishing below the apex, spiny above at the back; cells thickwalled.
Habit of flowering.-Male and female flowers on separate plants (dioicous). Male flowers surrounded with a rosette of leaves.
Veil (calyptra).-Split up one side.
Spore-case.-Narrowly oval with a narrow tapering neck somewhat pendulous, finally horizontal, somewhat inflated when empty, pale-yellow with a red rim.
Pedicel (seta).-Solitary, 1 to 1 1/2 inches long, arched above.
Lid (operculum).-Conical, tipped with a short, sharp point.
Teeth ( peristome).-As in the genus.
Spores.-Mature in spring.
Distribution.-Europe, Africa, and North America.