Clubmoss

Fan clubmoss (Diphasiastrum digitatum) grows in moist, acidic forests in South Carolina. Beech and oaks were the predominant tree species at this site.

Fan clubmoss (Diphasiastrum digitatum) grows in moist, acidic forests in South Carolina. Beech and oaks were the predominant tree species at this site.
Joey Williamson, ©2019 HGIC, Clemson Extension

My wife and I always enjoy hiking in the upper Piedmont of South Carolina because of the wide genetic diversity of plant life that we have in our state. It’s so fascinating to find a native plant in bloom or something that you haven’t seen very often while enjoying the walk in the woods. My eyes are trained typically on the sides of the trail, to see what is along the ground – to look for wildflowers, mushrooms, and other low growing plant material. What we infrequently encounter are sprawling patches of clubmoss.

Ground pine (Dendrolycopodium obscurum) is another species that grows well in moist, acidic forests in the Piedmont of South Carolina. This plant has produced a greenish-yellow strobili, on which its spores will be produced. These can be seen in the wildflower area of the SC Botanical Garden located in Clemson.

Ground pine (Dendrolycopodium obscurum) is another species that grows well in moist, acidic forests in the Piedmont of South Carolina. This plant has produced a greenish-yellow strobili, on which its spores will be produced. These can be seen in the wildflower area of the SC Botanical Garden located in Clemson.
Joey Williamson, ©2019 HGIC, Clemson Extension

Clubmosses are primitive vascular plants that look like miniature pines or cedars spreading over the forest floor. They evolved around 410 million years ago, even before higher plants and dinosaurs appeared on earth. Today, modern species only grow inches tall, but their ancestors grew as tall as 135 feet. The abundance of tree-like clubmosses, along with horsetails and ferns, dominated the Carboniferous period, and the woody clubmosses created much of the massive coal deposits that are mined today.

Until around 30 years ago, most clubmosses were placed in the genus Lycopodium, but taxonomists have since split these primitive little plants into several genera, and in South Carolina, these include Huperzia, Lycopodiella, Diaphasiastrum, Dendrolycopodium, and of course Lycopodium. Many species of these genera are found growing in areas of moist, acidic forests with seepages, but also in bogs and wet prairies. However, some species have adapted to grow well in dry or mesic forests, and even at higher elevations on balds, rock outcrops, and in forest openings with more sunlight.

There are approximately 7 genera and 11 species of clubmosses in South Carolina, and these seem to be indigenous primarily to the Piedmont and on the coastal plain of our state. One reason that they are considered primitive is because their manner of reproduction is by spores rather than by seeds. Many clubmosses send up “club-like” projections, called strobili, on which spore-producing packages (called sporangia) are formed.

These fan clubmoss (Diphasiastrum digitatum) have produced their multiple strobili on each stalk for spore release, and the spores are spread by air currents.

These fan clubmoss (Diphasiastrum digitatum) have produced their multiple strobili on each stalk for spore release, and the spores are spread by air currents.
Joey Williamson, ©2019 HGIC, Clemson Extension

Sometimes colonies of multiple species of clubmoss are found together, as ground pine and fan clubmoss grow in similar habitats.

Sometimes colonies of multiple species of clubmoss are found together, as ground pine and fan clubmoss grow in similar habitats..
Joey Williamson, ©2019 HGIC, Clemson Extension

Other clubmosses, such as this shining clubmoss (Huperzia lucidula), do not send up strobili for spore production, but have packets of spores formed in small sporangia at the base of their small scale-like leaves (called microphylls).

Other clubmosses, such as this shining clubmoss (Huperzia lucidula), do not send up strobili for spore production, but have packets of spores formed in small sporangia at the base of their small scale-like leaves (called microphylls).
Joey Williamson, ©2019 HGIC, Clemson Extension

However, spore production is not the only means by which clubmosses can spread. They also spread by underground stems (called rhizomes) that grow horizontally, and from these, additional small plants will appear a few inches away.

Clubmosses are extremely slow-growing plants and rely on mycorrhizal fungi to aid in nutrition and to complete their life cycle and growth, which from spore production and spread to making another mature plant may take as many as 20 years. In the past, clubmosses have been ripped from the ground to use as garland for Christmas decorations. However, with their growth that is so slow to recover from harvesting activities, these little clubmosses really should not be harvested. Additionally, they do not transplant well. Therefore, it is best to simply appreciate these beautiful, groundcover plants in their in natural habitats.

Reference:

Flora of the Southern and Mid-Atlantic States: Lycophytes. Alan S. Weakley, June 2019.

If this document didn’t answer your questions, please contact HGIC at hgic@clemson.edu or 1-888-656-9988.

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