SPECIES FACT SHEET
Common Name: Riparian loop lichen
Scientific Name: Hypotrachyna riparia
Division: Ascomycota
Class: Lecanoromycetes
Order: Lecanorales
Family: Parmeliaceae
Technical Description: Thalli foliose, with distinct upper and lower
surfaces (cortices). Photosynthetic partner (photobiont, phycobiont) is a
green alga. Thallus to 8 cm wide, irregularly branched, whitish gray to
bluish gray, loosely attached to substrate. Thallus lobes 1.5-5 mm wide,
flat or undulate, margins often flexed downwards just behind the apices,
with the apices erect and somewhat hooded, giving the tips an expanded,
capitate appearance, the upper surface of which is covered with
prominent patches of brownish, powdery soredia (soralia). Lower surface
of thallus black, brown on the margins, dense with elaborate, extensive,
dichotomously-branched rhizines up to 0.5 mm long, often visible from
above. Apothecia unknown.
Chemistry: upper surface of thallus K+ yellow, C-, KC-, P+ pale yellow,
UV-; medulla K+ yellow to orange, C-, KC-, P+ orange or red, UV-. With
atranorin and salazinic acid.
Distinctive characters: (1) numerous, dense, dichotomous and
repeatedly-branched rhizines, (2) soralia at the tips of the lobes, (3)
salazinic acid, and (4) whitish gray to bluish gray thallus. Similar
species: Hypotrachyna revoluta has (1) rhizines sparse and less
elaborately branched, (2) soralia scattered on the surface of the lobes but
not at the tips, (3) gyrophoric acid, and (4) the medulla is K+ reddish.
Hypotrachyna sinuosa also has soralia on the lobe tips but the thallus is
(1) yellowish-green or green, with usnic acid, and (2) the medulla is K+
yellow to reddish. Species of Parmotrema have (1) marginal cilia to 2 mm
long, (2) simple, unbranched rhizines, and (3) lobes up to 12 mm wide.
Species of Hypogymnia have grayish-green, hollow thalli. Other
descriptions and illustrations: McCune and Geiser 1997: 133 [in key as
"H. sp."]; McCune 1998: 448; McCune (no date).
Life History: Details for Hypotrachyna riparia are not documented
Apothecia have not been found and dispersal is restricted to vegetative
propagation via soredia, litterfall, and fragmentation.
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Range, Distribution, and Abundance: Endemic to Oregon. Currently
known from only two localities in the foothills of the central western
Cascade Range in Linn County.
National Forests: none documented; suspected on the Mt. Hood and
Willamette National Forests and in the Columbia River Gorge National
Scenic Area. BLM Districts: none documented; suspected on the Salem
and Eugene districts.
Rare, probably undercollected.
Habitat: On deciduous shrubs and trees in riparian forests below about
2,000 feet elevation, in foothills of the western Cascade Range, Oregon.
Known forest types are Fraxinus latifolia associations, but Hypotrachyna
riparia may occur in mixed riparian forests containing Pseudotsuga
menziesii, Tsuga heterophylla, or Abies grandis.
Threats: Air pollution, narrowing of riparian buffers, and overcollecting
may be the primary threats to Hypotrachyna riparia. Lichens of riparian
forests in major drainages along the east side of the Willamette Valley are
at risk from air pollution because of fog penetration and patterns of
prevailing winds. The lichen flora at some sites in this area has been
shown to be depleted (Klopatek et al. 2006; Geiser and Neitlich 2007).
Conservation Considerations: Consider revisiting known localities and
monitoring the status of populations. Lower-elevation streams are
usually privately owned and protection cannot be assured except on
federal lands. Search for new populations on federal and state lands.
Riparian buffers, if sufficiently wide, should adequately protect most
populations. Surveys in suitable habitat and protection of known sites
should be a priority.
Conservation rankings: Global: G1; National: NNR. Oregon Natural
Heritage Information Center: List 3 (S1).
Preparer: John A. Christy, with edits from Daphne Stone and Rob Huff
Date Completed: May 2008; updated March 2009 with addition of Attachment 2
(Map of Oregon and Washington locations).
ATTACHMENTS:
(1)
(2)
List of References
Map of locations of Hypotrachyna riparia in Oregon and
Washington
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Attachment 1 – List of References
Links are provided below to guide you to additional information that be
helpful in understanding this species. Included are links to illustrations,
photographs, maps and ranking information used to determine threats
and status by State Heritage Programs.
Geiser, L.H. & P.N Neitlich. 2007. Air pollution and climate gradients in
western Oregon and Washington indicated by epiphytic macrolichens.
Environmental Pollution 145: 203-218.
Klopatek, J.M., M.J. Barry & D.W. Johnson. 2006. Potential canopy
interception of nitrogen in the Pacific Northwest, USA. Forest Ecology
and Management 234: 344-354.
McCune, B. (no date). Photograph of Hypotrachyna riparia. USDA Forest
Service National Lichens and Air Quality Database and
Clearinghouse.
http://gis.nacse.org/lichenair/index.php?page=photos
_______. 1998. Hypotrachyna riparia, a new lichen from western North
America. Bryologist 101: 448-450.
_______ & L. Geiser. 1997. Macrolichens of the Pacific Northwest. Oregon
State University Press, Corvallis. 386 pp.
Oregon Natural Heritage Information Center. 2007. Rare, threatened and
endangered species of Oregon. Oregon Natural Heritage Information
Center, Oregon State University. Portland. 100 pp.
http://oregonstate.edu/ornhic/2007_t&e_book.pdf
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Attachment 2 - Map of locations of Hypotrachyna riparia in Oregon
and Washington
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