Friday, April 19, 2002
Name: British Soldiers or Cladonia cristatella
When and where seen: All year round; some in the Towle woods growing on dead wood, some in the Central Burying Ground growing in the soil. Last week I saw a whole army of them camped out in full sun on the wooden roof of a friend's dog kennel. I have also seen them growing along the complete length of a fallen power pole (in Chelmsford).
Distinguishing characteristics: This is one of our most easily recognized lichens. It is greyish-green and has "stalks" called podetia which have bright red spore-bearing caps. The podetia are up to an inch tall and always hollow; they may be branched at the tips and they grow in clusters. British Soldiers are relatively tolerant of pollution unlike some lichens which are so sensitive they are used to monitor air quality. There are 128 species in the genus Cladonia in North America. Some have red caps like these; others have brown caps; some have a cuplike shape.
The world of lichens: Lichens are composite organisms formed by the close association of fungi with algae. The fungal partner gets its food from carbohydrates manufactured by photosynthesis in the alga. The alga gets water from the fungus and is able to live in places where it couldn't survive on its own. Lichens are known as "nature's pioneers" since they can colonize bare rock and begin the process of soil formation.
Morphogenesis: The fungal component seems to have all the genetic information necessary to create the characteristic form of a lichen. The presence of the alga somehow triggers the cell transformation in a mysterious process called morphogenesis. This capability gives lichens a potential role as a research tool in investigating other cell transformations, and possibly in cancer research.
Reference: Lichens of North America, by Brodo, Sharnoff and Sharnoff, published in 2001, an excellent book. Big, over 700 pages, not a field guide unless you have a pack horse.
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 St, Carlisle, MA 01741 or to firstname.lastname@example.org.
© 2002 The Carlisle Mosquito