Plagiobothrys orientalis (L.) I.M. Johnst. Boraginaceae

Plagiobothrys orientalis (L.) I.M. Johnst.
Boraginaceae
Global Distribution:
Amphi-Beringian from Russian Far East and
Komandorski Islands to Aleutian Islands and Southwest
Alaska, disjunct near Haines.
Alaska Distribution:
Bering Taiga, Alaska Range Transition, Aleutian
Meadows, Coastal Rainforests.
Ecoregions Occupied: Ahklun Mountains, Lime Hills, Alaska Peninsula,
Kodiak Island; disjunct in Boundary Ranges.
Conservation Status:
S3 G3G4; BLM Watch.
Description25, 132
Calyxes 3 to 6 mm long,
pubescent with appressed hairs
2 cm
Corollas white, 2.5 to
4 mm wide
Stems pubescent
with appressed
hairs
Leaves sparsely pubescent with
short, stiff, appressed hairs;
upper surfaces sometimes
pustulate; margins ciliate
Leaves arising from
stem, 1 to 7 cm long, 3
to 8 cm wide
Illustration by Dagny Tande-Lid, courtesy of Stanford University Press
207
Plagiobothrys orientalis
General:
Annual herb from thin root; stems several, decumbent to
ascending, 10 to 20 cm long, pubescent with appressed hairs.
Leaves:
Stem leaves usually alternate, lower leaves sometimes
opposite, oblong to linear, 1 to 7 cm long, 3 to 8 mm wide,
sparsely pubescent with short, stiff, appressed hairs; upper
surfaces sometimes pustulate; margins ciliate.
Flowers:
Bracts numerous; flowers 3 to 4 mm in diameter; calyxes 3 to
6 mm long, pubescent with appressed hairs, lobed with
lanceolate lobes; corollas white, 2.5 to 4 mm wide.
Fruits:
Nutlets 2 to 2.5 mm long, ovoid, wrinkled.
© Forrest Baldwin 2011
Ecology
Elevation:
Known from near sea level to 100 m in Alaska.
Landform:
Estuaries and lagoons at or above tidal zone, lake shores,
river bars; also in disturbed sites such as airstrips and
ATV tracks.
Soil Type:
Mud, silt, sand, gravel.
Moisture regime:
Wet.
Slope:
Flat to gentle.
Aspect:
No particular aspect.
Vegetation type:
Sparsely vegetated.
208
Plagiobothrys orientalis
Associated species:
Carex lyngbyei, Cochlearia groenlandica,
Deschampsia cespitosa, Hordeum brachyantherum,
Equisetum arvense, Koenigia islandica, Leymus mollis,
Spergularia canadensis.
Longevity:
Annual.
Population estimate:
There are 15 known occurrences in Alaska; populations
usually consist of occasional or scattered individuals.
Similar Species25, 132
Plagiobothrys scouleri occurs in Alaska primarily to the north and east of the
range of Plagiobothrys orientalis; however, the two species may occur in similar
habitat in Southwest Alaska as well. The table below shows the differences in
morphological features between these two species. While Hultén (1968) reported
Plagiobothrys orientalis to have pustulate upper leaf surfaces and Plagiobothrys
scouleri to lack them,25 Welsh (1973) reported both species to sometimes have
pustulate upper leaf surfaces.132 The presence of pustules is not considered a
diagnostic figure in the table below.
Species
Leaves
Corollas
Plagiobothrys
orientalis
Up to 7 cm long,
3 to 8 mm wide
2.5 to 4 mm
wide
Plagiobothrys
scouleri
Up to 5 cm long,
1 to 4 mm wide
1 to 3 mm
wide
Calyxes
Hairs appressed; 3 to 6 mm
long; sepals 2 to 3 times longer
than nutlets
Hairs spreading-ascending; 2 to
3 mm long; sepals less than 2
times longer than nutlets
© Forrest Baldwin 2011
209
Plagiobothrys orientalis
© Forrest Baldwin 2011
210