SPECIES FACT SHEET
Common Name: Translucent orthodontium, orthodontium moss
Scientific Name: Orthodontium pellucens
Division: Bryophyta
Class: Bryopsida
Order: Bryales
Family: Bryaceae
Technical Description: Plants erect, 5-10 mm tall, yellowish-green
above, brown below. Leaves erect, 2.5-4 mm long, broadly linear, curved
in various directions to give mats a felty appearance, twisted and
flexuose when dry; cells of the lamina linear-rhomboidal, basal cells thinwalled and brownish; margins entire or distantly serrulate above the
middle, rarely coarsely toothed; costa slender, ending just below the
apex. Male antheridia and female archegonia in separate inflorescences
on the same plant (autoicous). Setae 7-14 mm long. Capsules 1.5-1.7
mm long, erect, ovoid to pear-shaped (pyriform), tapered to a short neck,
irregularly ribbed when dry, brownish yellow or becoming whitish with
age; peristome present, finely papillose. Distinctive characters: (1)
broadly linear leaves twisted to flexuose when dry, (2) antheridia and
archegonia in separate inflorescences on the same plant (autoicous), (3)
ovoid or pyriform capsules irregularly ribbed when dry. Similar species:
Orthodontium gracile has (1) linear to setaceous leaves somewhat flexuose
when dry, (2) antheridia and archegonia in the same inflorescence but
not mixed (paroicous), and (3) subcylindrical capsules smooth or only
slightly wrinkled, with a long neck. It is nearly impossible to distinguish
the two species using sterile specimens. Other descriptions and
illustrations: Bartram 1949: 154; Crum and Anderson 1981: 503; Crum
1994: 521.
Life History: Details for Orthodontium pellucens are not documented. Its
protonema is inconspicuous, forming buds and shoots in the usual
fashion of moss growth and development.
Range, Distribution, and Abundance: Southeastern and western United
States, Mexico, Central America, Caribbean, South America, Hawaiian
Islands. In the Pacific Northwest, known from California and Oregon.
National Forests: documented from the Rogue River-Siskiyou NF; not
suspected from other forests in Oregon and Washington. BLM Districts:
none documented; suspected on the Medford District.
1
Rare in Oregon, restricted to Sequoia sempervirens in the extreme SW
corner of the state.
Habitat Associations: Forming dense cushions or mats on stumps,
rotten logs and bark of living redwood trees, confined to redwood groves
near the Pacific Ocean. Sometimes on charred wood, or below gaping
wounds in trees. Associated vascular species include Sequoia
sempervirens and Polystichum munitum. Associated bryophytes include
Orthodontium
gracile,
Aulacomnium
androgynum,
Plagiothecium
denticulatum, and Lepidozia reptans. In the Pacific Northwest
Orthodontium pellucens and O. gracile are restricted to the redwood
forests of the Pacific Northwest (Norris and Shevock 2004). O. gracile may
have been introduced from Australia, but O. pellucens appears to be
restricted to the Western Hemisphere and is probably native. In the
southeastern United States O. pellucens occurs in the southern
Appalachian and Great Smoky Mountains on soil, rock, rotten wood, and
the bark of trees.
Threats: In the Pacific Northwest, the major threat to Orthodontium is
logging of redwood forests. Norris (1987) reported that O. gracile was
more abundant in old-growth redwood forest than in 100-year-old
second-growth, indicating that in our area old-growth provides optimal
habitat for the genus. Road construction, logging, and slash burning may
destroy habitat for up to 50 years until plants from adjacent stands can
repopulate sites. The redwoods that Koch (1952) reported from an
Oregon state park were later logged, leaving stands only on National
Forest lands.
Conservation Considerations: The best opportunities to protect
Orthodontium pellucens are on federal lands. Revisit known localities in
Oregon and monitor the status of the populations. Search for new
populations on federal lands. Protection of known sites from logging and
construction or maintenance of trails and roads will minimize risk to
populations.
Conservation rankings: Global: G5; National: N1. California: SNR;
Oregon: S1, List 2. Not known from Washington.
Preparer: John A. Christy
Date Completed: June 2007
2
Revised by: Rob Huff, February 2009
(Revision only clarified suspected potential range in Oregon to remove Coos Bay
BLM and add Medford BLM)
Revised by Candace Fallon, February 2011
(Revision only adds Attachment 1, Photos)
ATTACHMENTS:
(1)
Photos
References
Bartram, E.B. 1949. Mosses of Guatemala. Fieldiana (Botany) 25: 1-442.
Crum, H.A. 1994. Orthodontium. Pp. 520-521 in: A.J. Sharp, H. Crum &
P.M. Eckel (eds). The Moss Flora of Mexico. 2 volumes. Memoirs of the
New York Botanical Garden 69: 1-1113.
Koch, L.F. 1952. Bryophytes of Chetco River Redwood State Park,
Oregon. Madrono 11: 209-214.
Norris, D.H. 1987. Long-term results of cutting on the bryophytes of the
Sequoia sempervirens forest in northern California. Symposium
Biologica Hungarica 35: 467-473.
_______ & J.R. Shevock. 2004. Contributions toward a bryoflora of
California: I. A specimen-based catalogue of mosses. Madroño 51: 1131.
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
3
Attachment 1 – Photos
All photos by J. Harpel, under contract with the Oregon/Washington Bureau of Land
Management.
Alar and basal cells
Upper medial cells
Archagonia
Archagonia and antheridia
4
Perigonum
Leaf
Perigonum
Leaf apex
5
Dry sporophyte
Whole mount
Wet sporophyte
Peristome teeth
6