Buckthorn, Cascara, Chittam Bark
Rhamnus purshiana
Synonyms: Frangula purshiana, Frangula purshiana ssp. annonifolia, Frangula purshiana ssp. purshiana
Note: This taxon is referred to as Frangula purshiana ssp. purshiana in Washington.
The photo above shows what appears to be cascara
(Rhamnus purshiana ?) as seen on the east-facing slopes at about 5070'
of Crofton Butte on the southern slopes of Mt. Adams..........May
28, 2005.
The cup-shaped hypan and white petals that are present (the short white petals
are visible at the notches between the calyx lobes) indicate that this buckthorn
is probably Rhamnus purshiana rather than R. alnifolia. Photographed
at about 5070' of Crofton Butte on the southern slopes of Mt.
Adams.......................June 19, 2005. The hypan of the flowers of R. alnifolia tend to be wider or saucer-shaped and the petals are very
minute or generally lacking.
The photo above shows a close-up of the inflorescence of cascara
as seen at about 5070' of Crofton Butte on the southern slopes of Mt. Adams........June
19, 2005. Cascara (Rhamnus purshiana typically has 8-40 flowers in a
pedunculate umbel in the upper leaf axils. Its cousin, alder buckthorn (R.
alnifolia), typically has 2-5 flowers found in sessile umbels from the upper
leaf axils.
The photo above shows the leaves and axillary inflorescence of
what appears to be cascara as seen on the east-facing slopes at about 5070'
of Crofton Butte on the southern slopes of Mt. Adams........June
19, 2005.
The photo above shows a close-up of the leaf of cascara. This
leaf shows about 10-11 veins. Some of the leaves of this plant contained 8-9
veins per side of the leaf. Cascara typically has more than 8 lateral veins
to the side of the midrib, while R. alnifolia has fewer than 8 per side.
Most of the cascara on the eastern slopes of Crofton Butte (Mt. Adams Wilderness) were
small, with stems pressed against the ground or rocks, the stems no longer than
one to several feet. This photo shows a stem from one plant that had a single
branched stem climbing about 3-4 feet into the air.........June 19,
2005.
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The two photos above show the fall coloration of a cascara leaf.
Note the number of veins, which generally needs to be greater than 8 to be this
species.
Paul Slichter