The leaf (frond) of the Old World Climbing Fern (Lygodium microphyllum) is around 10 metres long. The structure of each leaf starts from the ground, the part where it attaches to a hairy horizontal stem. It ends at the crozier or fiddlehead, a coiled hook-shaped tip. The hairy horizontal stem that creep along the ground is called the rhizome.

Although the fern uses the same mechanism as the Mile-a-minute (Mikania micrantha) to get up its host plants, the part that goes around the support in the fern is actually part of the leaf and not the stem. I used to think that since the whole structure above the ground is the leaves, there should not be any branches from the leaves. Interestingly, I just saw a branch (fiddlehead) from a secondary stalk (rachis) this week on one that grew in my pot.

The fern is so common that it even sprout spontaneously from my pots along the balcony. Though the fern is considered to be a noxious weed in some countries, it is a native plant in this region. I have kept them since their leaves look really beautiful. To prevent one of them from overcoming one of my small Cherry Tree (Muntingia calabura) in the same pot, I have being regularly trimming off its fiddleheads at its very top end. This may be the reason for the growth of fiddlehead on the secondary stalk.

There are a total of 6 climbing ferns (Lygodium species) in Singapore as listed in the Flora checklist published in 2009. I have another one of them, Lygodium flexuosum growing in my pot. It has longer secondary leaflet (pinnule) compared to Lygodium microphyllum. Also, it never seems to spread to the surrounding area. The leaves simply sprout from the same small spot since the fern was first discovered in November 2011.