The arrestingly-named Solomon's seal (Polygonatum biflorum) is a handsome herbaceous plant. Its obscure common name is well-paired with its genus name, Polygonatum (which comes from the Greek gonatos) and means "many-kneed." Do plants have knees? What does all this mean?
We won't dwell on the unanswerable. There are a few dozen species in the
genus, but most find their home in East Asia, far from Caddo Parish,
Louisiana.
As far as names go, we have a problem; our current signage turns out to be inaccurate. The arboretum catalogue shows two collection dates for hairy Solomon's seal (Polygonatum
pubescens), both dating from the '90s. In 1991, Professor Ed Leuck collected a few plants from within Shreveport's city limits, on Line Avenue. A healthy patch still grows under the origianl red buckeye plants. In 1996 Jack Price of Blanchard donated six pots. Those plants have thrived on the southwest side of the long wooden bridge that runs from the Student Union Building to Mickle Hall. This patch continues to grow out into the lawn. Plants were collected from the grassy area and then transplanted to other areas of the arboretum, resulting in two additional patches of Solomon's seal. So, there are four total patches of Solomon's seal, and the original two patches are marked with green signs that read 'Solomon seal (Polygonatum pubescens)'.
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This is a relatively new patch of Solomon's seal. In 2023, we relocated a couple of plants to this spot, alongside a young black cherry (Prunus serotina). The black cherry has since grown tall, shading the Solomon seal. |
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The fruits were noticed several weeks ago. |
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Leaves alternate and have noticeable ridges or veins. |
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As the bell-like flowers of Solomon's seal descended daintily and prettily from the stalks, so now do the berries. |
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These fruits greatly resemble blueberries, although they are much more firm. Be careful! NC State Extension claims, "The berries, if eaten, are poisonous." |
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Dark blue round fruits measure less than ½ inch across. |
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Squeezing the large fruit opens the bright green interior, revealing numerous seeds. Seven seeds came from one fruit. Another yielded four seeds. |
Looking
at the current classification information for Polygonatum in the United
States shows P. pubescens and P. biflorum are the two major species east of the Mississippi. However, a distribution map clearly shows that P. pubescens
is not found in the Deep South; its homelands begin in the mountainous, cooler climates of Kentucky and Tennessee. Since the distribution
map for P. biflorum makes much more sense in covering the entire
eastern half of the USA, we needed to take a closer look at the plants
currently growing in the arboretum.
Descriptions for both species state the fruits are similar.
Descriptions differ for flowers, leaf size and shape, and the presence
of hairs. Since flowers aren't available in late summer, all four patches of
Solomon's seal were studied for leaf size and shape and the presence of
hairs.
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This egg-shaped leaf suggests P. biflorum. |
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These narrower, lanceolate-shaped leaves suggest P. pubescens. |
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These leaves are from two different patches. Do we have two different species or different light-conditions? The top leaf was found in full-shade. The bottom leaf was found in partial shade. |
Within the arboretum's collection, leaf size and shape suggest that we have two different species of Solomon's seal. However, the common names dwell on the presence of leaf hairs, and although the leaves varied in size and shape, no hairs were seen on any stems or leaves. All surfaces felt and looked smooth.
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This is the underside of the leaf. We see spots, but nothing fuzzy. |
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The underside is smooth. Leaves and stems from all four patches were examined, and nothing resembling hairs was detected. |
Based on species distribution and the total absence of hairs, we shall change the arboretum catalogue to note that we have Polygonatum biflorum, rather than Polygonatum pubescens. And, in the spring, we must study the flowers to see if they can give us any other clue as to the correct species label.
For more information about this species, please consult the following online sources:
USDA Plant Database Info for Smooth Solomon's SealUSDA Plant Database Info for Hairy Solomon's Seal
Flora of North America Species comparison for these two plants
Plants of Louisiana
NC State Extension