“We have the receipt of fern-seed, we walk invisible.” Shakespeare’s King Henry IV.
As you know ferns do not flower therefore they do not make seeds. How they reproduced was a mystery until the mid-1800’s. The Shakespeare quote above came from the idea that because fern ‘seed’ were invisible that if you could get them you too would be invisible.
I really enjoyed Eleanor Craig’s talk on ferns last month. We have been collecting ferns for years. At 25 native and 10 exotic species I thought we had a lot until I checked the facts. Snyder and Bruce’s Field Guide to the Ferns and other Pteridophytes of Georgia says there are 83 true ferns found in Georgia, some 400 different species in the United States, and about 10,000 world wide (published in 1986 so there are probably even more). Isn’t gardening humbling!
Eleanor showed us an example of how tiny and dust like the spores are. The spores are contained in sporangium, which are grouped into sori usually found on the undersides of fertile leaves. These little bumps are what many folks call in about thinking their ferns are infested. How the sori are arranged is often the key to fern ID. Ferns are tricky to identify and the juvenile stage can look very different from their final form.
Most of my original native ferns came from GNPS rescues and have grown into nice colonies. Two ferns that grow in swampy woods and along streams that look a lot a like are Sensitive Fern, Onoclea sensibilis, and Netted Chain Fern, Lorinseria areolata. They are both dimorphic, which means the fertile fronds carrying the spores are completely separate from the sterile fronds. Another common name for the Sensitive Fern is Bead Fern. Its fertile frond looks like beads while the Netted Chain Fern has its sori in chainlike rows. Since the fertile fronds on these two tend to persist I’ll try and bring some to the next meeting so you can see how different they are. Without the fertile fronds, identifying them is harder. While both have pinnatifid leaves, Lisa Betz taught me that the segments on Sensitive Ferns are opposite while the segments on Netted Chain are alternate.
As our gardens mature, the shade increases and gives us many more places to grow ferns.