Montana Field Guide

Plants: Acrocarpous, growing in clumps or cushions of erect shoots, seldom in large, crowded patches, deep to pale green above, brown below (FNA 2007). Stems 2-20 mm in height, seldom to 80 mm (Lawton 1971), frequently forking; rhizoids few; axillary hairs with the first 1 or 2 cells typically somewhat brown (FNA 2007).

Leaves: Pressed next to the stem when dry, spreading a little to more than 45 degrees, strongly bent back and downward above, wide and lance-shaped or tending to oblong, leaf tip curved and obtuse or nearly so or with a sudden short point, 0.5-2 mm in length (FNA 2007); margins flat (Lawton 1971); costa ending at or shortly before the leaf tip (FNA 2007).

Leaf Cells: Upper laminal cells isodiametric (FNA 2007), heavily papillose (Lawton 1971); proximal laminal cells short and quadrangular; leaf margins minutely scalloped from papillae (Crum & Anderson et al., 1981); costa in X-section with ventral superficial cells (FNA 2007), the ventral stereid band faint (Crum and Anderson et al., 1981) and absent distally (Flowers 1973), 1 series of 2-4 guide cells, a dorsal stereid band, and a dorsal superficial epidermis scarcely different from the adjacent stereids (FNA 2007).

Fruit ripens summer to autumn (FNA 2007).

The related Hymenostylium recurvirostrum, also attracted to water and limestone, has leaves that taper more than the often oblong leaves of G. aeruginosum (FNA 2007) and leaf edges that have one side curved back and downward when moist rather than both sides flat (Crum & Anderson et al., 1981). It also has ventral superficial cells of the costa that are long, slender, and without papillae; those of G. aeruginosum are square and papillose, only somewhat long in very compact leaves (FNA 2007).

Moist, calcareous stone, often residing near waterfalls and wet canyon walls. Ranging in elevation from 0 to 9840 feet (FNA 2007). Known in Montana from Carter, Cascade, Flathead, Glacier, Golden Valley, Lincoln, Missoula, and Sweet Grass Counties (Elliott & Pipp, 2016).

Dioicous and typically with numerous capsules (Flowers 1973). Perigonia bud-like, lateral, or situated at the top of the stem. Perichaetia solitary at the end of a long axis, with upper laminal cells heavily papillose and square, elongating toward the base. Seta spiraled clockwise (FNA 2007), 3-4 mm in height (Lawton 1971). Capsule glossy light brown (Crum & Anderson et al., 1981) with a broad opening (FNA 2007); theca 0.5-0.8 mm in length (Lawton 1971); operculum beaked, with straight cells; peristome teeth lacking. Calyptra draping hood-like (FNA 2007).