There has been a big shakeup in the genus Orthotrichum in the last few years. It has been known for awhile that Orthotrichum was polyphyletic (not all having a single common ancestor), and there have long been questions about where to place the members of that group that are both monoicous (having male and female organs on the same plant) and have the stomata (gas exchange pores in the capsule) on the surface (phaneroporous) as opposed to submerged in the capsule wall (cryptoporous). It is for these species that the genus Lewinskya was erected, named after an important figure in the present understanding of the family Orthotrichaceae, Jette Lewinsky-Haapasaari.
Because of my specimen having a distinctly ribbed capsule that narrowed abruptly (strangulated) before flaring to the peristome (the mouth of the capsule), as well as being monoicous and having phaneroporous stomata, I had felt pretty good calling it Orthotrichum affine, and the fact that it was now called Lewinskya affinis was merely interesting to me. Until I read that, when they applied molecular testing to members of the new genus, it became apparent that Lewinskya affinis, a species found on 4 continents, was in fact a species complex, comprising as many as seven different species. So, with a slightly pained sigh, it was back to the drawing board.
Eventually I found a paper by Vigalondo et. al (2020) that had a key and descriptions of the new species, and in a weird quirk of Internet fate I was allowed to access it, although when I went back to link it to this profile I just found the abstract and a paywall. But by then I had re-examined my specimens, and come to the conclusion that I probably had Lewinskya pacifica (L. affinis as presently circumscribed is considered to be a strictly Eurasian and North African species). But I say probably because, while that is the best overall fit, due to location, substrate, and lack of netlike structures on the exostome (the exterior ‘teeth’ of the peristome), still the key calls for L. pacifica to have a blunt (obtuse) apex to the leaves, and these have mostly pointed tips. So I’ll just leave it here with that ambiguity, since some leaves did have relatively blunt apexes.
Description-Small (up to 2cm tall by 4cm wide) clumps or cushions of dull green moss with small (2.1-3.3mm long by .5-.9mm wide) lanceolate leaves; capsules slightly immersed in the surrounding leaves (parichaetial leaves) to slightly emergent; capsules strongly ribbed and strangulated when dry, with phaneroporous stomata on the lower half; exostomes rectangular cells, seldom split, lacking fenestration (windows or holes); monoicous.
Similar species–Lewinskya pseudoaffinis has cancellated (netlike) ends to the exostomes, and less strangulated capsules; L. arida and L. praemorsa are found on rock in drier locations; Ulota sp. have crisped and twisted leaves when dry; Orthotrichum and Pulvigera sp. are cryptoporous or dioicous, or both.
Habitat-Epiphitic on hardwoods; probably a common resident on street trees in urban areas.
Range-Pacific Coast; primarily west of the Cascades, and in sw Oregon and nw California in our region.
Reproductive timing– forms sporophytes almost year around.
Eaten by-Various slugs, snails, insects, woodlice, springtails, and nematodes, and the capsules are probably also taken by small birds.
Etymology of names–Lewinskya honors Jette Lewinsky-Haapasaari, a renowned expert on the family Orthotrichaceae. The specific epithet pacifica refers to it being found along the Pacific Coast.