Biocrusts of Northern Arizona National Monuments, Post 2: Moss key

This is my second post on biocrusts of National Monuments of Northern Arizona. See yesterdays post for a lichen key, here's a moss key. Liverworts were not observed by surveyors, but they are likely out there. The keys apply to Wupatki, Walnut Canyon, Sunset Crater, Montezuma Castle (& Well), and Tuzigoot National Monuments.

Field-based key to common biocrust mosses of National Monuments of the southern Colorado Plateau and Colorado Plateau-Sonoran Desert ecotone

1a) Upper leaves or entire plant white or silvery due to lack of chlorophyll; plants usually small (0.5 mm tall)................Bryum argenteum complex (may include B. argenteum, B. lanatum)

1b) Plants not whitish or silvery; plant sizes various............. 2

2a) Plants light green to yellowish, stems up to several cm long, frequently branched with a creeping growth form ……Brachythecium spp.

2b) Plants various colors, stems usually less than 1 cm, not branched or only sparingly branched and.….3

                        3a) Plants lacks awns (hair points on leaf tips), light green to black...4

4a) Plant light green, large (>1mm common) tongue shaped leaves (may be contorted when dry) with mucro at apex, Almost always bearing straight, erect sporophytes (~1-2.5 cm tall); older sporophytes exhibit cylindrical capsules topped with a characteristic white column ....................................Tortula inermis          

4b) Plant forest green above and reddish brown below when dry, shorter plants with linear-lanceolate leaves (sometimes contorted, sometimes ~ imbricate); if present mature sporophytes red with inclined capsule .............................................Ceratodon purpureus

                        3b) Plants with awns (usually whitish and toothed); colors various..5

5a) White awns longer than plant height; often giving appearance of white fuzzy tuft because plant is buried or inconspicuous ............Pterygoneurum spp. (Almost always P. ovatum but can’t be keyed in field without sporophyte)**

5b)White or yellowish awn length less than plant height; plants are generally above ground and easy to see .....6

6a) Awn is a yellowish extension of an acuminate leaf tip, wider at base; plant yellowish green or golden, mostly < 1mm tall .......................7

7a) Plant yellowish green, rarely in dense cushions; arid regions....Bryum kunzei 
7b) Plant golden yellow with a magenta colored stem (view wet), frequently in dense cushions; prefers shrub canopies in higher elevation areas.....Bryum caespiticium

6b) Awn is white and ~ same width along its entire length, plants light green, or darker (not yellow).....8

8a) Plants tall, often > 3mm height; plants lime green-dark green at top, reddish at base; leaves slightly twisted around stem when dry squarrose-recurved (curling back > 90º back from stem) when wet, costa frequently red …………...Syntrichia ruralis

8b) Plants small-med, usually less than 3mm tall: plants dark green-blackish at top, brown at base; leaves not twisted around stem when dry, patent (not curling back > 90º), costa never red…....Syntrichia caninervis

** If sporophyte is present:

5aa) Due to a short seta, the sporophyte capsule is immersed in leaves or barely sticking out, calyptra splits in 2 or more places, plants about 1mm high and green......Pterygoneurum subsessile
5bb) Seta a few mm long, sporophyte capsule exerted, calyptra splits along a single seam, plants very small and awns are much more more visible...............................Pterygoneurum ovatum