At the end of April I was introduced to Carol Kleppin, a lovely lady who lives in Summerville, South Carolina, not far from Charleston. It turns out that Carol has discovered a very strange plant in her garden. She described it to me as a low groundcover of unknown origin that spreads quickly and might soon cover her lawn. Or worse. Time for a botanical road trip.
I went to Summerville with the intention of making a herbarium specimen or two of Carol’s plant and getting a good identification for it. In fact, this low little thing was moving fast in her garden, only a few inches high – and it formed quite a substantial ground cover all by itself.
It turns out that this is related to different types of fern-like plants called “clubmosses”. These come from a very ancient lineage and reproduce like ferns from spores.
Carol’s plants were soft to the touch and formed branching mats close to the ground. Tiny ovate leaves are found in rows on the sides of the stem and even smaller ones in rows at the top of the stem. The tips of the stems branch several times, forming branches that are flattened at the tips. Sometimes the plants form mounds and rise into the air above the ground. When the time is right they will produce very small cone-like structures from which to shed the developing spores capable of starting new plants.
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This little groundcover (which I think is quite pretty, with its glossy, slightly iridescent leaves and stems) is native to southern Africa and was actually commercially available here in the US. As you might expect, a plant that reproduces by spores and is easily grown in pots or terrariums is likely to spread if given the chance – and that seems to be happening in this backyard.
Indeed, Carol’s near-home discovery is evidence that this species enjoys weeds in the Southeast. So far it has only been found outside of cultivation in very few locations in Alabama, Georgia and the two Carolinas. But it looks like it could spread even further.
If you happen to spot plants in your garden (or wherever) that seem out of place or otherwise odd, consider reporting them to a botanist at your local herbarium. Botanists tend to be very pleasant, inquisitive creatures, and they may want to come out and take a look.
Answer: “Matted Grain Moss”, Selaginella kraussiana.