Subtropical Australian Tree Fern, Sphaeropteris Cooperi (Hook. ex F. Muell.) R. M. Tryon, Found Modestly Established in Oregon

2008·1.7 MB·English

by  Wendell Wood

Subtropical
Australian Tree
Fern, Sphaeropteris
cooperi (Hook, ex
F. Muell.)
R. M. Tryon, Found Modestly Established Oregon.—The
in
exotic Australian
Tree
Fern, Sphaeropteris
cooperi (Hook, ex F. Muell.) R. M. Tryon, synonym
Cyathea
cooperi (Hook, ex Domin,
F. Muell.) has been discovered an
in easily
accessed canyon on
the southern Oregon
approximately
coast, 11 miles north
of Brookings, Oregon
(Fig.
1).
Last descending
fall, after a steep trail to explore sea caves and arches
at
"Secret Beach" below Samuel Boardman
H. State Scenic Corridor, an Oregon
came
State Park, across very woods
a large fern in the along lower
I the portion
of Miner Creek. The location T39S R14W sw% - midway
is of Sec. 16 roughly
between "Arch Rock" and
"Natural Bridges". The was
plant photographed,
and
from
scales a portion of the large diameter lower were
petiole
collected.
With hand
brown
a
lens, tiny angled teeth can be seen along the
scales'
-
margins
a vegetative characteristic pinpointing genus and
this suggesting the
most
likely species. At Oregon State University upon Kenton Chambers'
Dr.
recommendation, was
material sent Alan Smith
to Dr. R. at the University of
California, Berkeley, herbarium. Dr. Smith provided information on how
to
make
a cursory and made
identification in the he then
field, a positive
identification of the species from the pressed and dried specimens were
that
sent him.
to
On
a return trip to the area, a total of three plants were located along the
bottom of Miner Creek canyon within approximately 125 yards from
or less the
beach, and another sample was and OSU
collected sent for deposit in the
herbarium
(OSC) Chambers'
at Dr. request. State Park have been
officials
and
notified, it will be their decision whether to further monitor, or perhaps
eradicate, this unexpected subtropical escapee.
assumed
It is that the bottom of this small coastal canyon provides thermal
protection from freezing, while being isolated enough to protect the exotic ferns
from
direct contact with the marine and Queensland,
salt air spray. In Australia,
the native habitat of this species reported to be in gullies in rain forest
is
(Medeiros et al., Amer. Fern 82:27-33. 1992). Of the three tree fern plants
J.
located, two were along canyon bottom and one was on
the a vertical
cliff
immediately below
a small waterfall. All plants located were within 100 of
feet
each and were
other, all observed from the trail or just barely off the trail.
NE
Sphaeropteris cooperi native Australia but widely planted and
to
is is
used USA. warm, humid
horticulturally in the has been cultivated in parts of
It
the country, but unfortunately has become too well naturalized in Hawaii,
where
it is still aggressively spreading (Medeiros et al, 1992). According to Dr.
may
Smith, this be the time Sphaeropteris cooperi has ever been found
first
-
naturalized anywhere in the continental United States including Florida,
and Smith
California, elsewhere. Dr. writes: "It is not treated in Flora of North
America North of Mexico (FNANM), Vol. 1993. As far as know, there are no
2,
I
members
of the tree fern family, Cyatheaceae, naturalized in the continental
USA."
-
"Oregon
Sphaeropteris cooperi. Photocredit \
Fronds of the Oregon plant showed no Dr. Smith writes: "Often,
fertile sori.
become
and depending on light and other factors, this species does not fertile
more Trunks
until the trunks are substantial, several meters or in length. are
cm
where
reported to 12 meters 15 diameter, in the flora of Australia, is
tall, it
The Oregon probably no more than about
native." plant of the three
tallest
is
two
meters
high.
unknown how may
While have been introduced
these plants to this
is first
it
location, ferns can establish miles away from any parent plant with their
fertile
small, easily dispersible wind-borne spores. very possible that a cultivated
It is
somewhere
garden plant in coastal southern Oregon could be the source.
However,
measures
cultivators of this tree fern species caution that special
have to be taken to protect plants from freezing, which considered lethal for
is
Sphaeropteris cooperi. Since the fern was discovered in nature in 2007, have
I
now
located it 12 miles to the south where two larger fertile plants are growing
closely beside a commercial building in Brookings, Oregon. The residents say
they planted
at this location five years ago. Also, in Brookings located a
it
I
commercial nursery
that sells this tree fern in one gallon cans.
Where to see in Oregon.—Along Samuel H. Boardman State Scenic
it
an Oregon on Hwy.
Corridor, State Park, pull off the west side of 101,
immediately north of Miner Creek, which signed on highway and
the located
is
midway A
between the 345 and 346 mile
downhill,
posts. steep, l^-mile
trail
SHORTER
NOTES
n5
what
leads Oregon
to
State Parks
calls "Secret Beach".
Here, the sand beach
with rock and
arches another
botanically
interesting small side canyon
are best
when
explored
the
tide is at 1.5 feet or below. The easily observed
Australian
tree fern located the bottom what map
is at of
a the
at trailhead terms a "Cat
While some
Trail." attempt was made
look more
to for tree ferns up
farther the
canyon, abundance
the
of salmonberry
bushes,
increased stream and
fall flow,
overall rugged topography
strongly
limited physical as well as observational
When
descending
the from Hwy.
and
trail 101, the
first, smallest, tree fern
is
across the canyon
(south
side) at a small, user-trampled overview on
your
left,
shortly before you come
The
to the beach. fern there on
a
is vertical face
cliff
and down
immediately
stream
of a 12 which
foot, free-falling
waterfall,
lies
below an
erosion-control,
concrete lining of the upper portions of Miner
Creek.
All Sphaewpteris
cooperi seem
plants be below
to this concrete
lining, a
structure not obvious
to the casual observer. Binoculars will help
to identify
this smaller-sized
first tree fern across the narrow canyon.
The
and most
largest accessible from which
fern, material
for identification
was
collected, growing above
is just the only small foot bridge over Miner
way
Creek,
located a short from the beach. Once you
reach
the spur
final trail
down
to Secret Beach, continue
to the left, starting back uphill (east) but as
though you
were
going to proceed on the Oregon Coast
Trail farther south. In
another
50 immediately
feet, across the foot bridge but observable from
either
side, is the large tree fern the From
to left of the trail. here continue uphill on
same
this trail for 25 yards to a short spur to the Here one can view
easily
left.
another
fairly large tree fern growing above bottom
just the of the creek's north
bank. This spot could
also potentially be accessed by up
hiking the stream
bottom
above
the footbridge during times low
of stream
flow.
To
see the OR
tree fern in cultivation in Brookings, near the north end of
Hwy
town
along
go
101, to Coastal Copiers, 1041 Chetco Ave.
The
author thanks Alan
Dr. Smith, University and
of California, Berkeley,
Kenton
Dr. Chambers, Oregon
State University, for help in the preparation of
this report.—Wendell Wood, Oregon Wild, PO Box CA
1783, Crescent
City,
95531.