Guide to Liverworts of Oregon: Marsupella emarginata (Ehrh.) Dum.
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Marsupella 1b plants dioicous > Marsupella 5b plants not julaceous > Marsupella 6a leaf divided .1 -.3 > Marsupella 7a terrestrial > Marsupella emarginata
Synonym: None.
Special Status: None.
Recognition: Small to medium plants with transversely inserted, bilobed leaves. In typical plants the leaves are recurved and spread widely from the stem, giving it a pectinate appearance. The most similar species is M. sphacelata . Comparing the two, M. emarginata has marginal cells small vs. marginal cells larger; M. emarginata has basal cells elongate vs. not elongate; M. emarginata has margins revolute vs. margins plane; M. emarginata has leaves bilobed less than 0.3 vs. leaves bilobed 0.3-0.6; M. emarginata has lobes sometimes apiculate vs. lobes not apiculate.
Distribution: Grows on rocks or tightly packed mineral soil; frequent on soil of road cuts in coastal strip; common on shady, seepy rocks of road cuts and narrow stream canyon walls; widespread in western Oregon from low to middle elevations.
Comments: Marsupella emarginata is represented by the typical var. emarginata (var. tubulosa is east Asian and eastern North American). It matches the description as given in Schuster (1974) with little deviation. The epidermal cells of the stem are little differentiated from the layers of cells beneath, the latter being somewhat thickened. The oilbodies are quite uniformly two per cell, exceptionally more, in the median leaf cells; basal cells frequently have more than two oilbodies, up to six, where they are spherical rather than the typical ellipsoidal-fusiform oilbodies of median cells. These basal cells are elongated, up to three or more times as long as wide, and uniformly thickened without clearly developed trigones. This basal cell feature will differentiate M. emarginata from M. sphacelata: in the latter species the basal cells are mostly isodiametric and show nearly normal, bulging trigones. However, when one species is growing in the typical habitat of the other, it will mimic the features of the "home" species (the Vavilov Effect).
The elaters of M. emarginata in Oregon are more uniformly 2-spiral than Schuster reports (Schuster 1974, p. 81, footnote 37). Only rarely will one of the spiral bands split into two for one or two gyres, whence a 3-spiral condition is produced. The spirals of the elaters are rather wide, like ribbons instead of wires (Wagner 3276). The elaters of M. emarginata are larger than those of M. bolanderi, which are about half the size and consistently have three narrow ribbon-like spirals. See illustration below which compares them at the same scale.
The plants of the Oregon coast, where the plants are abundant on rocks and tightly packed soil
Sweet Creek Trail, Lane Co., Oregon.
Male shoot; Excelsior Pass Trail, Whatcom Co., Washington. DHW
4766.
Female shoot; Excelsior Pass Trail, Whatcom Co., Washington. DHW
4766.
Female shoot; Excelsior Pass Trail, Whatcom Co., Washington. DHW
4766.
Vegetative shoot; Wolf Creek, Lane County, Oregon. DHW
6907.
Leaf; McKenzie River Trail, Linn Co., Oregon. DHW
m2750
Leaf cells with oil bodies; McKenzie River Trail, Linn Co., Oregon. DHW
m2750
Leaf cells with oil bodies; McKenzie River Trail, Linn Co., Oregon. DHW
m2750
Cells with oil bodies containing eye-spots; McKenzie River Trail, Linn Co., Oregon. DHW
m2750. Cell measurements: average 23.8 μm long, 16.8 μm wide; n = 25.
Elaters and spores. Excelsior Pass Trail, Whatcom County, Washington. DHW 4766.
Comparison of elaters of Marsupella emarginata and Marsupella bolanderi at the same scale.