Guide to Liverworts of Oregon: Pellia alpicola R.M. Shust. ex L. Söderstr., A. Hagborg & von Konrat
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Pellia 1a involucre short tubular > Pellia alpicola
Synonyms: Apopellia alpicola (R.M. Shust. ex L. Söderstr., A. Hagborg & von Konrat) Nebel & D. Quandt, Pellia endiviifolia subsp. alpicola R.M. Schust. nom. inval., Misapplied names: Pellia endiviifolia (Dicks.) Dumort., Apopellia megaspora (R.M. Shust.) Nebel & D. Quandt
Special Status: None.
Recognition: Unisexual thalli with short, angled to erect, laciniate involucres will separate this from other species of the genus. Male plants can be sectioned to distinguish this from P. neesiana. Pellia alpicola lacks thickening of cell walls in mid thallus that P. neesiana develops. The stalked slime papillae are three or more cells long in P. alpicola, while the other two regional species of Pellia have two celled slime papillae.
Distribution: In wetlands or along streams, on peat or soil; mainly restricted to high mountains in our area but also in the Columbia River Gorge with other arctic-alpine disjunct species. Doyle and Stotler (2006) report this from California as Pellia endiviifolia.
Comments: In their synopsis of the liverworts of North America (Stotler and Crandall-Stotler 2017) the genus Apopellia is recognized as distinct from Pellia on the basis of a study by Stütz, Quandt, and Nebel (2016). The elevation by segregating a previously well recognized subgenus to genus status is not controversial. Using DNA sequence data to generate a cladogram supporting the distinction was the primary significance of the article. Recognizing Apopellia has little value for field bryologists and creates a conflict for herbarium curators who file specimens alphabetically but wish to keep closely related taxa together in the cabinets. For this reason I recommend continuing to use the subgenus rank for Apopellia.
What puzzles me is Stütz et al. (2016) do not follow their own suggestion that "western" A. megaspora is a distinct species from A. megaspora of eastern North America. Being possibly paraphyletic, the distinction is strongly supported by their phylogenetic tree. Then, oddly enough, they would name all of the western US specimens south of Canada as Apopellia megaspora Typical Pellia megaspora, with type locality in Maine, is primarily an eastern N. America taxon. Its morphology is definitely different, particularly in the form of the involucre. The western plants are clearly distinct and most will be Pellia alpicola. A specimen I collected in Oregon in 2007, which I distributed as Pellia alpicola, was used in their study cited as Apopellia megaspora.
In 2007 I sent fresh material of this species to Ray Stotler and he replied,
"The Pellia arrived in great condition today. It is P. endiviifolia subsp. alpicola R. M. Schust. He treats it in a footnote in Vol. 5: 450 but says more about it where it is described in Hattori 70: 145. 1991. Norton is correct in that the eastern N.A. stuff is not P. endiviifolia but, according to Schuster 'they [eastern NA] appear to refer to P. megaspora . . .' Nice find! Characters - long uniseriate ventral hairs, dentate/ciliate pseudoperianth that lies at an angle (not erect). Best regards, Ray" (R. Stotler, pers. comm.)
I trust Ray Stotler's opinion. I am pleased that Söderstrom, et al. (2013) made the necessary combination to recognize Pellia alpicola at species rank. Whether this name will prove appropriate for all material of Pellia subgen. Apopellia in the Pacific Northwest remains to be determined by further study. This study will have to include ample sampling of fresh material to be trustworthy.
Pellia alpicola. Involucre. Staley Ridge, Douglas Co., Oregon. DHW m2302.
Pellia alpicola. Looking down on involucre from above. Staley Ridge, Douglas Co., Oregon. DHW m2302.
Pellia alpicola. Marginal cells with oil bodies. Staley Ridge, Douglas Co., Oregon. DHW m2302.
Pellia alpicola. Ostioles on male plant. Black Meadows, Lane County, Oregon. DHW m2284.
Pellia alpicola. Section through stioles on male plant. Black Meadows, Lane County, Oregon. DHW m2284.
Pellia alpicola. Ventral hairs (slime papillae). Staley Ridge, Douglas Co., Oregon. DHW m2302.
Pellia alpicola. Ventral hairs (slime papillae). Staley Ridge, Douglas Co., Oregon. DHW m2302.
Pellia alpicola. Oneonta Gorge, Multnomah Co., Oregon. DHW s.n., 23 July 2014.
Pellia alpicola. Stained ventral hairs (slime papillae). Oneonta Gorge, Multnomah Co., Oregon. DHW s.n., 23 July 2014.
Pellia alpicola. Stained rhizoids. Oneonta Gorge, Multnomah Co., Oregon. DHW s.n., 23 July 2014.