Syn. 693. 1860. Amblystegium serpens var. juratzkanum (W.P.Schimper) Rau & Hervey, Cat.No.Amer. Musci 44. 1880.
Plants in loose and rather thin mats, green to yellow-green. Stems to 5 cm long, prostrate to weakly ascending, irregularly branched. Stem leaves spreading, often almost squarrose, to 1.2 mm, 2.5–3: 1, symmetric and lanceolate to narrowly ovate-lanceolate, not at all plicate, acuminate with the acumens straight, little changed moist or dry. Branch leaves smaller than stem leaves, less spreading but not otherwise different. Leaf margins plane and entire or weakly serrulate in distal 1/3, not decurrent. Median cells smooth, to 8 µm wide, long rhomboidal, about 3: 1, rather thick-walled, not pitted. Alar and basal cells very short rectangular, somewhat enlarged in a single row across the leaf. Apical cells gradually somewhat more elongate than median cells. Costa extending 1/3–2/3, not reaching the acumen, without an abaxial spine. Pseudoparaphyllia narrowly lanceolate to linear, strongly overarching the bud. Axillary hairs of 3 similar cells, to 50 µm with no basal brown cells, not offset from leaf insertion. Rhizoids rarely produced on older prostrate stems, 12–14 µm broad at insertion, smooth, mostly not branched.
Autoicous with perigonia near perichaetia. Perichaetial bracts costate, narrowly lanceolate, closely pressed to base of seta with its cells uniformly long and straight, to 8: 1. Seta brown to red-brown, smooth, to 2 cm long. Capsule brown to red brown, inclined to horizontal, not strangulate. Urn to 1.5 mm, short cylindric to oblong, strongly arcuate, 2.5–3.5: 1. Median exothecial cells irregularly arranged in vertical rows, to 20 µm wide, mostly 2: 1 but some to 4: 1, with moderately thick, red-brown walls and with stomata restricted to neck. Suboral exothecial cells arranged in up to 4 strongly differentiated rows, somewhat enlarged and isodiametric. Operculum conic to apiculate, about 1/8 as long as urn. Annulus present as two rows of enlarged cells, not revoluble. Exostome to 500 µm long, horizontally striate below, smooth to papillose above, yellow- to red-brown. Endostome segments low papillose, open on keel, about as long as exostome with basal membrane about equal in length to the segments. Cilia 2–3, nodose. Spores finely papillose, to 15 µm.