Montana Field Guide

Plants: Pleurocarpous. Growing in large mats or thick tufts (Crum & Anderson et al. 1981; Lawton 1971), green, green with golden tones, somewhat brown to russet, or seldom red (FNA 2014) with a golden tinge (Crum & Anderson et al. 1981) in very open areas (FNA 2014). Stems 5-15 cm in length, or may be longer in floating plants (Lawton 1971), with few branches (Crum & Anderson et al. 1981); possessing a central strand; hyalodermis wanting; rhizoids or their initials located on stems or leaves in various places (FNA 2014).

Leaves: Somewhat dense, the tips falcate and pointing toward the same side of the stem, or distant and spreading (Crum & Anderson et al. 1981), lanceolate (Lawton 1971) or slenderly ovate, narrowing into a long acumen, curved like a sickle or occasionally straight, moderately to barely cupped (FNA 2014), not furrowed, 2-4 mm in length (Crum & Anderson et al. 1981); margins or parts of the margins toothed or faintly so; (FNA 2014); base not noticeably auriculate (Crum & Anderson et al. 1981); costa ranging from half the leaf length to subpercurrent, sometimes shorter, infrequently paired (FNA 2014).

Leaf Cells: Alar region in a slender, crosswise triangle, not strongly demarcated (FNA 2014), the cells shy of square, somewhat swollen; distal cells long and narrow, flexuose; basal cells at the attachment frequently golden (Crum & Anderson et al. 1981), occasionally pitted, with thick walls (Flowers 1973).

Although fluitans means floating, the plants are connected to the substrate rather than floating (Crum & Anderson et al. 1981).

Plants with sickle-shaped leaf tips and absent of capsules may be confused with comparable Sarmentypnum (or Sarmenthypnum) species. Sarmentypnum plants have alar regions that are more strongly demarcated than those of Warnstorfia. They are also dioicous rather than autoicous and often have red (FNA 2014) or purplish-red colorings rather than red with golden tinges (Crum & Anderson et al. 1981).

The alar areas of the similar W. exannulatum generally extend further distally (FNA 2014).

Ombrotrophic, occasionally in areas with abundant nutrients (somewhat polluted) (FNA 2014); wet soil and humus (Elliott 2016), bogs, fens, rocks in seepy areas or with water-holding cavities (FNA 2014), swamps, lake margins (Flowers 1973), frequently underwater when water is high (Crum & Anderson et al. 1981). Elevation: 0-11,480 feet (FNA 2014).

Autoicous (FNA 2014). Sporophytes common. Seta 5-7.5 cm in length. Capsule 2-3 mm in length, bowed, ascending to drooping; cilia in twos (Crum & Anderson et al. 1981).