Syntrichia ruralis
Syntrichia bartramii
sidewalk screw moss
5–15 mm.
2–10 mm.
clasping at base, infolded and twisted around the stem when dry, wide-spreading (in smaller forms) to squarrose-recurved when moist, lingulate-ovate, 1.5–3.5 × 0.75–1.25 mm, canaliculate to keeled;
margins tightly revolute in the proximal 7/8 or more, entire;
apices emarginate to acute;
costa excurrent into a serrate (or occasionally only faintly serrulate), hyaline awn that is often red or sometimes broadly hyaline at base, weakly to strongly papillose on the abaxial surface and often serrate near the apex because of projecting cell ends, red-brown;
basal cells abruptly differentiated, narrowly rectangular, 35–70(–90) × 11–18 µm, quadrate to narrowly rectangular at the margins;
distal cells quadrate to polygonal, 8–12 µm, with 3–6 papillae per cell, bulging, somewhat obscure.
infolded and spirally twisted around the stem when dry, wide-spreading when moist, lingulate to spatulate, 1.25–2 × 0.5–0.75 mm;
margins plane, entire, except for papillose crenulations, not bordered;
apices acute to truncate or occasionally emarginate;
costa excurrent into a conspicuously tapered, serrate awn 0.1–0.6 mm, red or yellow, sparsely to densely spinulose abaxially;
basal cells abruptly differentiated, with somewhat thickened cross walls, those at the margins narrower;
distal cells irregularly polygonal, isodiametric, 9–13 µm, obscure, bulging and densely papillose, with 4–6 papillae per cell, moderately thick-walled and not collenchymatous.
red, 5–10 mm.
dioicous.
dioicous (perigonia and sporophytes unknown).
red-brown, 2–3.5 mm, straight, with an abrupt neck;
operculum 1.25–1.75 mm, brown;
peristome ca. 1.25 mm, the upper divisions twisted ca. 2 turns, red, the basal membrane white, about 1/3 the total length.
11–15 µm, papillose.
asexual reproduction absent.
asexual reproduction absent.
Syntrichia ruralis
Syntrichia bartramii
Syntrichia ruralis generally has conspicuously squarrose-recurved leaves when wet, with margins recurved nearly to the apex, distal portions of the costa toothed abaxially because of projecting cell ends, and relatively small laminal cells. The decurrent, hyaline base of the awn sometimes used to distinguish S. ruraliformis is not reliable and can, on occasion, be found in S. princeps, S. papillosissima, and S. norvegica. Specific distinctions in the S. ruralis complex are subtle, for the most part, requiring cross sections of leaves and stems, and careful measurements. The leaves of S. princeps and S. obtusissima are narrowed near the middle, whereas those of S. papillosissima, S. norvegica, and S. ruralis are widest about one-third the way up from the base and then taper to the apex. The stem of S. princeps and S. obtusissima has a strong central strand of thinner-walled cells, the costa has a group of hydroids just abaxial to the guide cells, and the basal cells in the leaf are relatively wide. In S. papillosissima, S. norvegica, and S. ruralis, the stem lacks a central strand, the costa lacks hydroids, and the basal cells in the leaf are relatively narrow.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Diagnostic features of the rare Syntrichia bartramii include plane leaf margins and the costa excurrent into a tapered, serrate awn. In contrast with those of S. fragilis, the leaves of S. bartramii are not fragile and have awns, somewhat smaller, more obscure distal cells, less well-defined groups of basal cells, and plane margins. Without propagula, plants of S. laevipila can be separated from S. bartramii by the abaxially smooth costae and smooth awns, and also by larger and less obscure leaf cells. It should be noted that leaves of S. bartramii sometimes show 2-stratose patches (one or a few cells in width). In contrast, S. chisosa has leaves that are almost completely 2-stratose distally, less twisted when dry, and merely mucronate at the apex.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
BC
CalFlora
Flora NW
MI Flora
MO Plants
PNW Herbaria
WildflowerSearch
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USDA Plants Database
