[Milkvetches: The Genus Astragalus East of the Cascade Mountains of Oregon and Washington]
Howell's Milkvetch, Howell's Milk-vetch
Astragalus howellii
Synonym: Astragalus misellus var. howellii
The photo above shows the flower of Howell's milk-vetch as seen along Oregon Highway 216 about one mile east of the Deschutes River...........April 19, 2007.
The
photo at right shows the long slender pod of Howell's milk-vetch which tapers
to a point at both ends. Note the fairly deep groove that runs the length of the
ventral pod surface...........May 20, 2000.
Characteristics:
Howell's milk-vetch is a perennial wildflower with several prostrate
to erect stems to 20 cm long. The leaves and stems are covered with numerous
short, grayish and incurved hairs. The compound-pinnate leaves bear 11-27 leaflets
with linear-lanceolate to narrowly oblong leaflets, 5-14 mm long and 1-2.5 mm
wide. The leaflets vary from glabrous above to soft-hairy on both surfaces.
(See the photo below.)
The flowers are whitish-yellow and reside in loose racemes
of 5 to 25 flowers atop flower stems from 10-20 cm long. The flowers measure
from 6 to 16 mm long. The calyx is about half that length, with teeth about
1/2 to as long as the calyx tube. The calyx is covered with soft, crisp, white
and brown hairs. The flowers have a banner that is erect or curves approximately
90 degrees from the axis of the wings and keel. The wings are narrow, w-3 mm
longer than the keel.
The pods are spreading to pendulous, obliquely linear-oblong
in shape. Both ends of the pods are acutely pointed and the ventral surface
bears a noticeable groove (See photo at right.). The pods range from 15-30 mm
long, and 2.5 to 4.5 mm wide.
Habitat:
Howell's milk-vetch is found on the dry grassy and sagebrush plains and slopes
along the Columbia River.
Range:
Howell's milk-vetch is generally found on the flat plains and rolling hills
south of the Columbia River between The Dalles, OR and Umatilla, OR.
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Additional close-up photos of Howell's milkvetch as seen at the summit of US Highway 197 at Tygh Ridge in north-central Oregon............May 14, 2010.
The photo above shows the long leaf with its many closely spaced
leaflets of Howell's milk-vetch. Photographed on BLM land on south-facing slopes
above the east bank of the Deschutes River along Gordon Ridge Rd to the southwest
of Biggs, OR..........April 23, 2000.
The photo above shows a frontal view of the flower banner of Howell's milk-vetch as seen along Oregon Highway 216 about one mile east of the Deschutes River..........April 19, 2007.
The photo above shows another closeup of the
calyx and corolla of Howell's milk-vetch. Note that the wings are much longer than the keel. Photographed on BLM land on south-facing slopes above the east
bank of the Deschutes River along Gordon Ridge Rd to the southwest of Biggs,
OR..........April 23, 2000.
The photo above shows the light yellow corolla with its banner reflexed backwards up to 90 degrees and the hairy calyx with slender clayx lobes up to one-half the length of the calyx tube. Photographed on BLM land on south-facing slopes above the east bank of the Deschutes River along Gordon Ridge Rd to the southwest of Biggs, OR..........April 23, 2000.
The photo above shows a front view of the
banner, wings and central keel of Howell's milk-vetch. Note the yellowish lines
on the creamy banner. Photographed on BLM land on south-facing slopes above
the east bank of the Deschutes River along Gordon Ridge Rd to the southwest
of Biggs, OR..........April 23, 2000.
The photo above shows the slender, pendant pods of
Howell's milk-vetch. They appear similar to those of threadstalk milk-vetch
but the latter plant is significantly taller and more bushy while
the former is low growing. Photographed on BLM land on south-facing slopes above
the east bank of the Deschutes River along Gordon Ridge Rd to the southwest
of Biggs, OR..........May 20, 2000.
Paul Slichter