Fan clubmoss (Diphasiastrum digitatum) grows in moist, acidic forests in South Carolina. Beech and oaks are the predominant tree species at this site.
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 (which lasted 359.2 to 299 million years ago), and the woody clubmosses created much of the massive coal deposits that are mined today.
Ground pine (Dendrolycopodium obscurum) is another species that grows well in moist, acidic forests in the Piedmont region of South Carolina. This plant has produced a greenish-yellow strobili, on which its spores will be produced. Ground pines may be found in the wildflower area of the SC Botanical Garden in Clemson.
Joey Williamson, ©2019 HGIC, Clemson Extension
Genera
Until around 30 years ago, most clubmosses were placed in the genus Lycopodium, but taxonomists have since split these primitive little plants into a number of 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 are indigenous primarily to the Piedmont region and on the coastal plain of the state.
Reproduction
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.
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.
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 clubmoss species are found together. 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 they 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
Growth Rate
Clubmosses are extremely slow growing plants and rely on mycorrhizal fungi to aid in nutrition and to complete their life cycle and growth. It may take as many as 20 years to make another mature plant from spore production and spreading. In past years, clubmosses have been ripped from the ground to use as garland for Christmas decorations. However, because of their slow growth and recovery from harvesting activities, these little clubmosses really should not be harvested. Additionally, they do not transplant well. Therefore, it is best to appreciate these beautiful, evergreen groundcovers in their natural habitats.
Reference:
- Flora of the Southern and Mid-Atlantic States: Lycophytes. Alan S. Weakley, June 2019.
Originally published 01/21
