Guide to Liverworts of Oregon: Rivulariella gemmipara (A.W. Evans) D.H. Wagner
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HOME > 1 plants leafy > 3 leaves not divided, not ciliate > 6 oil bodies 2+ or unknown > 7no small dorsal lobe > 10 succubous > 11 anisophyllous > 12b leaves lobed > if rhizoids red, stems red > 38a shoots wider than 1 mm >39
------39a underleaves conspicuous > 40b underleaves narrow to lanceolate > 43b underleaves narrow to round > 45b strictly submerged aquatic > Rivulariella gemmipara
-----39b underleaves inconspicuous > 55b leaves succubous > 58b shoots >1.2 mm wide > 59b lobes acute or oil bodies >12 > 60a strictly submerged aquatic > Rivulariella gemmipara
Synonym: Chiloscyphus gemmiparus Evans.
Special Status: ORBIC List 1.
Recognition: Aquatic; leaves round to bilobed, inserted from strictly transverse to nearly horizontally; underleaves sporadically produced ; gemmae often present profusely, but sometimes totally absent; stems attached to rocks greatly flattened, horizontal and ascending stems cylindrical; rhizoids scattered but present only on prostrate stems attached to rocks in streambeds. Plants leafy, yellow-brown to dark greasy-green in life, drying blackish, 5-6 mm wide to 1.5 cm long. Shoots prostrate or erect, each with a different morphology: (1) prostrate shoots usually closely appressed to substrate, attached by numerous rhizoids; leaves attached obliquely, overlapping only slightly; underleaves tiny or absent; sex organs absent; (2) erect shoots not closely appressed to substrate, generally lacking rhizoids; leaves attached nearly transversely; underleaves usually present, large, especially near the tip of fertile shoots and often poorly differentiated from lateral leaves (isophyllous); sex organs present. Leaves on both types of shoots obovate, widest above the middle, emarginate to deeply notched at apex, the leaves appearing shallowly bilobed when notched. Gemmae composed of 2-5 cells at maturity are produced in masses along the edge of leaves at shoot tips. Typical fertile shoots are bisexual, the antheridia in bracts immediately below the archegonial tip (paroecious). Unfertilized shoots often produce small, adventitious male shoots. Perianths oblong, closed at the mouth, with five longitudinal furrows or pleats, forming only out of water in the splash zone, after fertilization. Despite this mind-bogglingly range of variation, the species is not too difficult to place. Because this species is an obligate submerged aquatic, identification of sterile material involves ruling out all other aquatics, of which there are only few in Chiloscyphus, Jungermannia, Scapania and possibly Plagiochila.
Distribution: On rocks in permanent streams at high elevations in the Cascades. Originally described from Utah, now known from California, Oregon, and the Aleutian Islands. In Oregon it is known from the Seven Lakes Basin south of Crater Lake and in the Three Sisters Wilderness, where it is found in the Mesa Creek headwaters (Wagner m1769), in the upper tributaries of Linton Creek, and tributaries of Fall Creek on the SW side of South Sister (Kofranek 2493, Dewey 080712-1036).
Comments: This species was originally placed in the wrong genus. A new genus name has been selected and a paper with formal description has been published (Wagner, 2013).
Three Sisters Wilderness, Lane Co., Oregon. DHW
3453.
Three Sisters Wilderness, Lane Co., Oregon. DHW
m1769.
Three Sisters Wilderness, Lane Co., Oregon. DHW
m1769.
Broken Top, Three Sisters Wilderness, Deschutes Co., Oregon. Dewey 080712-1036
Broken Top, Three Sisters Wilderness, Deschutes Co., Oregon. DHW m2842. Squashed shoot tip showing development of fasciculate gemmae.
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