The Carlisle Mosquito Online

Friday, December 12, 2003


Many-forked Cladonia

"May the gods of the tundra grant me lichen until I become lichen myself."
from Northern Latitudes by Larry Millman.

I have been looking around for some reindeer lichen (or reindeer moss as it is sometimes called) to write up for the Christmas season. I was sure I had found some and took it to a lichen identification session at Garden in the Woods for confirmation by an expert. I got the lump-of-coal award.

Name: Many-forked Cladonia or Cladonia furcata. Worldwide, there are approximately 400 species in the genus Cladonia, and 128 of these occur in North America. Some have red tops like British Soldiers (Cladonia cristatella); others have brown tops; some have cuplike structures. The species name, furcata, is from the latin word furca meaning fork The suffix —ata makes the noun into an adjective. So this is a Cladonia with something forklike about it. Furcata is widely used in naming plants and animals that have some forklike characteristic — for example the fork-tailed storm petrel is Oceanodroma furcata.

When and where seen: Many-forked Cladonia can be found all year round. This sample was found in the Green Cemetery on November 28, alongside the stonewall dividing the old part of the cemetery from the newer part. It was growing on the ground in with the moss. It stood an inch or two taller than the moss.

Lichen identification: Lichens can be difficult, even impossible, to identify without a microscope, some chemicals, and an understanding of lichen vocabulary. The body of a lichen is called a thallus and there are three common growth forms. Crustose lichens tend to be small, scale-like, and very tightly attached to the substrate. Foliose lichens are more leaf-like than the other forms. The thallus is flattened and has an upper and lower surface. Fruticose lichens have no upper or lower surface. They may be erect and twiggy, or threadlike and pendulous. Those who don't spend much time outdoors may have seen fruticose lichens as shrubbery in model train landscapes.

Distinguishing characteristics: The many-forked Cladonia is a fruticose lichen. The greyish-green stalks called podetia are slender, mainly smooth, hollow and up to 4 or 5 inches tall. The podetia are forked or branched, and forked again at the tips into 2s, 3s and 4s forming an axil in which there is an opening. With a sharp eye or a hand lens you can see the opening in the axil and also see that the tiny tips are themselves forked. The tips are reddish brown.

The lichen lifestyle: Lichens represent a long-term intimate relationship (dare I say marriage) between fungi and algae, or sometimes between fungi and cyanobacteria. The relationship provides privileges not available to either partner as an individual. For example, neither fungi nor algae are able to colonize rocks except as a lichen team. A lichen is a kind of organic farm in which the fungal farmer grows algae crops in a protective living greenhouse.

References: Lichens of North America, by Brodo, Sharnoff and Sharnoff, published in 2001, a very comprehensive book with lots of color photos; Lichens of British Columbia, by T. Goward has lots of useful line drawings and can be downloaded in sections from the Web. It has a long ugly URLask Google to find it.

Submissions for the Biodiversity Corner are encouraged from everyone. You can write the column or tell me what you saw and I will write it. The organism doesn't have to be unusual. The only requirements are that it exists in the wild and was seen in Carlisle. Send a note to Kay Fairweather at 392 School Street, Carlisle MA 01741 or to

Author's note: In last week's Mosquito, I recommended a book of adventure tales called Lost in the Arctic by Larry Millman. For people who enjoy poetry, Larry's book Northern Latitudes would be a good choice.

© 2003 The Carlisle Mosquito