Guide to Liverworts of Oregon: Porella arboris-vitae (With.) Grolle
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1b plants not peppery tasting > 2a underleaves strongly toothed > 3a ventral lobes NOT decurrent > Porella arboris-vitae
Synonym: Porella fauriei (Steph.) Hatt. [misapplied]; Porella vernicosa var. fauriei [misapplied]
Special Status: ORBIC List 2 - possibly extinct. Will be of extreme conservation concern once it is relocated in the Columbia River Gorge, Multnomah County, Oregon, its only known site in North America.
Recognition: Looks somewhat like P. cordaeana except its leaves, lobules, and underleaves have more and sharper teeth. The most distinctive character seems to be the nondecurrent ventral lobes and more distinctly and regularly spinous margins on underleaves and lobules of main shoots.
Distribution: On rocks with some soil as reported from the Columbia River Gorge, Oneonta Gorge, Triple Falls, Multnomah County, Oregon (Potter s.n. DUKE).
Comments: The notion that there is only a single site for a species otherwise known from another continent is not as strange as it seems. This is parallel to the situation with Radula brunnea on Saddle Mountain. This handsome plant is found only there in North America; otherwise it is distributed broadly in eastern Asia. The Columbia River Gorge is as likely a place for a relict population as Saddle Mountain. Relocating the population would be of great interest. I have searched the trailsides to Triple Falls several times without success. I suspect the trailside rocks that Potter explored no longer exist on today's trail.
Note that Hong (1983) did not read the handwriting correctly on the specimen's label and thought that "Oneonta" was "Veneta," and therefore lists Lane County as the site location. However, "Triple Falls" is clearly written immediately after "Oneonta" and Triple Falls is a well known feature of Oneonta George. There are a number of specimens at DUKE from the Portland, Oregon area which had been collected by Potter around this time. The provenience of the Porella specimen is not likely a curatorial lapsus.
Porella arboris-vitae. Oneonta Gorge, Multnomah County, Oregon. Potter s.n. (drawing by S. Allison)
Porella arboris-vitae. Oneonta Gorge, Multnomah County, Oregon. Potter s.n.
Porella arboris-vitae. Oneonta Gorge, Multnomah County, Oregon. Potter s.n.
Porella arboris-vitae. Oneonta Gorge, Multnomah County, Oregon. Potter s.n.
Porella arboris-vitae. Oneonta Gorge, Multnomah County, Oregon. Potter s.n.
Porella arboris-vitae. Oneonta Gorge, Multnomah County, Oregon. Potter s.n.
Porella arboris-vitae. Oneonta Gorge, Multnomah County, Oregon. Potter s.n.