Shasta Knotweed

Another Mount Lassen wildflower/shrub photographed in Lassen Volcanic National Park in California:

Shasta knotweed (Polygonum shastense) is an inconspicuous plant. Climbing up Mount Lassen I noticed these native perennials while looking around as Leonard was studying some rock samples. The specimens appeared very small and seemed to be struggling for survival. So I chose to continue to the peak, assuming I would find some better plants further along. I did not see any other Shasta knotweeds along the trail. Although I knew approximately where the Shasta knotweeds were I almost could not find them again. Thankfully we did find them.

A member of the Buckwheat Family (Polygonaceae), Shasta knotweed has woody, gnarled, brown, creeping stems arising from a woody root. The short stems are prostrate or weakly ascending.

The leathery, glabrous (no hairs) leaves are oblong to lanceolate with a pointed tip. Shasta knotweed leaves are very small (5 to 15 mm) and with age the leaf margins roll under.

The flowers are borne at the base of the upper stem leaves. The tepals (structures not either sepals or petals) are rose or white in color with a darker midvein. Shasta knotweed has no true petals. Rose and white flowers can occur in the same inflorescence. There are 5 to 8 stamens and a triangular pistil with a three-lobed style.

Shasta knotweed fruits are brown, shiny, smooth achenes.

Considered a wildflower as well as a shrub, Shasta knotweed grows on rocky or gravelly slopes between 7,200 and 11,000 feet. It is found in Oregon, Nevada and California, mostly in the Sierra Nevada.

The species name, shastense, means that the plant grows on Mount Shasta in California.

I am glad that we did not miss this unassuming little plant.

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