(official burnet)
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Photo of Sanguisorba officinalis by Jacob Frank
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Great burnet is a distinctive forb with dark red-purple ovoid head of flowers above divided leaves, found growing on gravelly riverbanks, marshes, and lakeshores in boreal regions of the park. The plants grow 20-90 cm tall from a thick caudex. Leaves are long-petiolate, 15-30 cm long with 7-15 leaflets. The leaves are divided pinnately, the leaflets stalked,
ovate to
oblong and with
serrate margins. The
inflorescence is a dense, rounded cylinder of flowers, long-stalked above the leaves. Each small flower has 4 maroon
sepals, and no petals. The four
stamens are not much extruded from the flowers, with red
filaments. The fruits are single-seeded
achenes. This species is easily differentiated from
S. stipulata (which is much more common in the park) by its red flowering heads, and its boreal marshy habitat.
This species is perennial and
deciduous. It typically flowers mid-summer. The leaves turn purple red in the fall before being shed.
Sanguisorba officinalis is
monoecious with bisexual flowers. Little is known about the pollination of great burnet. In other parts of its range, claims have been made for insect pollination or insect pollination and self-compatibility (
Naruhashi et al. 2001;
Winter et al. 2008). Seeds do not have any special dispersal adaptations.
Sanguisorba officinalis is an incompletely circumpolar species with an interrupted, boreal-montane distribution ranging westward across Eurasia to Europe, and primarily coastal in North America, reaching northern California, Pennsylvania and Maine. In Alaska, S. officinalis occurs occasionally in most of the mainland south of the Arctic slope including the Brooks Range, the Seward Peninsula, central and southwest Alaska, through the southeastern panhandle, but is apparently absent from the Alaska Peninsula and Aleutian chain.
Details are shown in the Plots & Charts found at right, depicting recent Denali data.
An infrequent species, this species is known from a small range of mid-elevations, the average occurrence at 587 m. All but two of the known occurrences of great burnet are from slopes lower than five degrees. The two on steeper slopes were on southern aspects.
Details are shown in the Plots & Charts found at right. For more on how to interpret these figures, visit Understanding Data Presented.
Wet to moist sites.
