The downy Solomon’s seal (Polygonatum pubescens) is a perennial herbaceous plant with simple erect stems which are hairless (2). The stems grow from horizontal white rhizomes, which bear distinctive round scars from the growth of previous year. The scars on the rhizome are said to resemble royal seals and this is thought to have been the origin of this species’ common name (2).
The leaves of the downy Solomon’s seal are simple, with parallel veins and smooth edges, and are elliptic in shape. The upper surface of the leaves is green and the lower surface is pale. The flowers of this plant are arranged in hanging clusters of two to four and are green to yellowish-green. The fruits of this plant are small bluish-black berries (2). The downy Solomon’s seal can be distinguished from similar species by the presence of hairs on the veins on the underside of the leaves (3).
- Also known as
- hairy Solomon’s seal, small Solomon’s seal.
- Convallaria pubescens, Polygonatum boreale, Polygonatum farwellii, Sigillaria pubescens.
- Height: up to 1.1 m (2)
- Flower length: c.1 cm (3)
Downy Solomon's seal biology
The downy Solomon’s seal blooms from April to June (2) (4). This plant is highly self-incompatible, which means that it rarely self-fertilises (3) and depends on insects for pollination. The main pollinators are thought to be bees from the family Anthophora, particularly the wandering bumblebee (Bombus vagans) and perhaps some fly species (3).
Downy Solomon's seal range
The downy Solomon’s seal is endemic to eastern North America (2) where it is found around the Great Lakes (3).
Downy Solomon's seal habitat
The downy Solomon’s seal can be found in rich deciduous and mixed wood forests, and thickets (2).
Downy Solomon's seal status
The downy Solomon's seal has not yet been assessed by the IUCN.
Downy Solomon's seal threats
There are not currently known to be any threats to the downy Solomon’s seal, but habitat destruction and conversion of land for agricultural use may threaten this plant in the future. The downy Solomon’s seal is so dependent on insect pollinators that the plant’s fecundity has been suggested as a good marker for pollinator bee population health (3), although this dependence may threatens this plant’s future because global bumblebee populations are declining (5) (6).
Downy Solomon's seal conservation
There are not currently known to be specific conservation measures in place for the downy Solomon’s seal. However, this species is classified as endangered in Illinois under the Endangered Species Protection Act (7) (8), which prohibits the possession, collection, transportation and sale of this plant without a permit (8).
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- A plant that sheds its leaves at the end of the growing season.
- A species or taxonomic group that is only found in one particular country or geographic area.
- A measure of fertility, such as sperm count or egg count or the number of live offspring produced by an organism.
- Describes a small, non-woody, seed bearing plant in which all the aerial parts die back at the end of each growing season.
- A plant that normally lives for more than two years. After an initial period, the plant usually produces flowers once a year.
- The transfer of pollen grains from the stamen (male part of a flower) to the stigma (female part of a flower) of a flowering plant. This usually leads to fertilisation, the development of seeds and, eventually, a new plant.
- Animals that in the act of visiting a plant’s flowers transfer pollen grains from the stamen (male part of a flower) to the stigma (female part of a flower) of a flowering plant. This usually leads to fertilisation, the development of seeds and, eventually, a new plant.
- An underground, horizontal plant stem that produces roots and shoots.
- Fusion of male and female sex cells (gametes) from the same individual. In contrast, in cross-fertilisation, two different individuals are involved.
Catalogue of Life (May, 2014)
Northern Ontario Plant Database - Polygonatum pubescens (April, 2014)
Barber, K.N. (1988) Development of a Monitoring Protocol for Using the Fecundity of Polygonatum pubescens as an Indicator of Impacts of Forest Sprays on Bumblebees. Forest Pest Management Institute, Canadian Forestry Service, Ontario, Canada. Available at:
University of Texas Lady Bird Johnson Wildflower Center - Polygonatum pubescens (May, 2014)
Grixti, J.C., Wong, L.T., Cameron, S.A. and Favret, C. (2009) Decline of bumble bees (Bombus) in the North American Midwest. Biological Conservation, 192: 75-84.
United States Forestry Service - Bumble Bees of the Eastern United States (May, 2014)
United States Department of Agriculture, Department of Natural Resources - Illinois List of Endangered and Threatened Flora (May, 2014)
United States Department of Agriculture, Natural Resources Conservation Service - Polygonatum pubescens (May, 2014)