downy arrowwood

Downy arrowwood occurs in North America east of the Great Plains from Quebec to Manitoba south to South Carolina and Tennessee. It is common in northern and eastern Minnesota, mostly absent in the southwestern quarter of the state. It grows in moderately moist to dry upland woodlands in full sun, partial sun, or deep shade.

Downy arrowwood is a medium-sized shrub that rises on multiple stems from a woody, spreading root system.

Sources

2, 3, 4, 5, 7, 8, 24, 28, 29, 30.

Species
This species was named for the 19th century polymath Constantine Samuel Rafinesque, who made important contributions to botany and zoology. It was published in 1820 as “Viburnum rafinesquianum”. The species epithet is a latinized correctable misspelling of the honoree’s last name. The corrected name is “Viburnum rafinesqueanum”. Many authoritative sources use the corrected spelling, but about the same number use the name as originally published. Which is correct? An argument can be made for either spelling.

Family
There is some disagreement about the correct placement of the genera Sambucus and Viburnum. They were formerly included in the family Caprifoliaceae. In 2003, the Angiosperm Phylogeny Group proposed moving them to the Adoxacea family (APG II), but the Nomenclature Committee for Vascular Plants approved the conservation of Viburnaceae. In 2016, Angiosperm Phylogeny Group proposed to “super-conserve” Adoxacea (APG IV), but the General Committee for Botanical Nomenclature rejected the proposal.

Currently (2023), some sources, including USDA PLANTS and NatureServe, place the genera Sambucus and Viburnum in the Caprifoliaceae family. Some sources, including ITIS and NCBI, place them in the Adoxacea family. Almost all other sources, including APG IV, World Flora Online, Plants of the World Online, GRIN, GBIF, and iNaturalist, place the two genera in the Viburnaceae family.

There are two varieties of downy arrowwood, rafinesqueanum and affine. Both varieties occur in Minnesota. Their ranges appear almost identical, and many collected specimens have intermediate characteristics. Nevertheless, the varieties are generally, though not universally, accepted.