Racomitrium Moss

Description

Plants are a bit smaller than typical Bucklandiella heterosticha, a bit darker at the tips of the shoots. It is much more similar to Racomitrium sudeticum, such that Lawton thought this was merely a form of that (Lawton 1971, 1972). Racomitrium brevipes shares a bistratose leaf margin with Racomitrium sudeticum and a costa which is mostly 3 cells thick from base to midleaf. However, Racomitrium brevipes has a much wider and flatter costa, 6-9 cells wide adaxially. The costa anatomy is very distinctive. The costa of Racomitrium brevipes is broad, U-shaped, not blocky (quadrate) distally and quite shallow proximally. The pseudopapillose leaf cells in sections appear nearly globular above the vertical walls in section. Pseudopapillae are very prominent, visible even when looking down, with 40X objective, on the dorsal surface of the leaf apex. The hair point is strongly spinulose, even inside the adaxial trough. The hair points are spinulose on the back as well as along their margins.