This is based on Maine Mosses by Bruce Allen and BFNA v27.
L. albidum - Plants in low, compact cushions usually less than 10 cm in diameter; Stems less than 1 cm (rarely to 4 cm); Leaves 2-5 mm, limb subtubulose, erect to wide-spreading, straight; Limb usually shorter than length of sheath; frequently bears sporophytes (61% of collections).
L. glaucum - Plants in tall, compact cushions or turfs sometimes in excess of 1 m in diameter; Stems mostly 1-1.25 cm (rarely shorter); Leaves mostly 3-9 mm, limb concave to subtubulose, erect-spreading, sometimes falcate-secund; Limb longer than (up to X3) length of sheath; sporophytes uncommon (16% of collections).
In Maine a large majority of the plants are L.glaucum and L.albidum is typically found within a few miles of the coast. The separation of small L. glaucum from L. albidum is challenging. The best criteria for recognizing L.albidum is the combination of: compact, short cushions; leaves 2–4 mm; reflexed limb usually shorter than the sheath. The of length of the sheath relative to the length of the limb provides the most consistent way to separate the two species.
Crum & Anderson used a transverse section of the thick lateral regions of costa to differentiate the two species. However the use of the number of leucocysts on both sides of the chlorocyst layer is not a reliable distinguishing feature. This character varies on plants from the same colony and on different sides of the same leaf. There is no consistent pattern for each species across the geographical range. Correlation with other characters is inconclusive.
last update 2024-Mar-11