Fall Fern Season!

Leathery Grape Ferns

I seem to use a lot more photos of grape ferns than other ferns, but they are so special, especially in the fall, I can't resist.

Leathery Grape Ferns (Sceptridium multifidum) are the largest grape ferns in our region, and are outstanding in their size and stoutness. The ones we visit in VT are up to about 10" tall with the fertile frond. The leaves are large, close to the ground and very leathery or succulent. What surprised us this year was the different amounts of bronzing the fronds of different plants were displaying. We had not visited them this late in the season (October 17), so maybe they just develop this coloring later in the fall, or maybe this is a special year. Most field guides and texts describe Leathery Grape Ferns as having evergreen leaves throughout the winter until they wither in the new growing season. There were numerous plants at this site that had some amount of yellow or bronzing, and a few were darker than the nice coloring in this photo. I really like the strong colors of these fertile fronds. I also like the way the edges of the sterile frond are slightly lighter and fine toothed. The fall coloring seems to accentuate this feature. The fertile frond on this plant was not as tall as some, but the sterile frond was nice and large. There were more than 50 plants on the site, some smaller and some larger than this one.

While looking on the web for other sources that might mention the fall coloring, we found some interesting information about the Leathery Grape Fern. One paper about Leathery Grape Ferns in the western states mentions that the sterile fronds may be reddish or copper tinged; the rest don't mention it. We also learned from these other articles that these ferns are dependent on mycorrhizal fungi for their water, minerals and nutrients. They are generally found growing in sandy open areas and poor acidic soils, so this may explain how they are able to thrive in such an area. One article (Botrychium multifidum: A Technical Conservation Assessment by David Anderson, 2005) also mentioned that each plant may have 1000s of spores in their 20-100 sporangia, "possibly the highest number of spores per case of all vascular plants". It also mentions that these spores may be dispersed by wind, but they may also be distributed as they pass through the digestive tracks of animals.

We have not been able to find any Leathery Grape Ferns in western MA, so if you do see some, we would love to see them as well!

Happy Fall Ferning!