Plants: in dense turfs, dark green. Stems: 1â2 cm, comose, innovations comose or somewhat elongate and evenly foliate; not strongly radiculose. Leaves: green, twisted to contorted when dry, oblong or ovate, concave, (0.5â)1â2 mm, not much enlarged toward stem apex; base not decurrent; margins plane or revolute to mid leaf, limbidium somewhat indistinct, in 1 or 2 rows; apex acute, sometimes apiculate; costa percurrent in proximal leaves to sometimes short-excurrent in distal leaves, awn denticulate; proximal laminal cells 3â4:1, same width or sometimes wider than more distal cells; medial and distal cells rhomboidal, 12â16 µm wide, 3â4:1, walls thin. Specialized: asexual reproduction by leaf axil gemmae, green or green-brown. Sexual: condition autoicous. Seta: 2â3 cm. Capsule: brown, pyriform, symmetric, 2â3 mm, mouth yellow; operculum short-conic, apiculate; peristome reduced; exostome teeth yellow basally, hyaline distally, lamellae usually straight mid tooth, pores absent along mid line; endostome variable, not adherent to exostome, basal membrane low, segments with narrowly ovate perforations, sometimes reduced, cilia variable, absent or occasionally present and well developed, appendiculate or nodose. Spores: (28â)30â40 µm, finely papillose, green. Phenology: Capsules mature JunâAug. Habitat: Soil over serpentine rock, in serpentine rock crevices Elevation: low elevations (0-100 m) Distribution: Del., Md.
Discussion: Of conservation concern.
Ptychostomum reedii is a highly distinctive and very rare local endemic, not likely to be confused with any other species in eastern North America. The costal awns are slender. The setae are brown, unlike the red or red-brown setae of other species in sect. Cladodium. Plants from Delaware have abundant filiform gemmae in the leaf axils.