A couple of weeks ago, I had to cut down a sixty seven year old White pine near my house. And yesterday I found the most beautiful lichen that must have fallen from that tree, something called Fringed Wrinkle lichen, a lichen that thrives in the uppermost branches of Eastern white pine and Hemlock trees.

I am frankly fascinated by lichen. Because this summer has been so hot and dry I have spent more time in the woods than usual. Mushrooms have been scarce and I have been looking at various lichens marveling over their ability to deal with drought conditions. During dry spells lichen become dry and crispy but don’t expire. Lichens grow on rocks, trees, and in the soils in many different environments. Around the house I must have at least twenty different types of lichen, maybe more. I haven’t counted all of them.

Lichen is composed of two organisms that arise in a symbiotic relationship. One is an alga or cyanobacteria and the other is a fungus. The algae live among the filaments of fungi. Evidently the fungus is the predominant partner because it determines the majority of the alga’s characteristics, from its curious shapes to its fruiting/spore producing bodies. Some lichens have more than one algal partner.

Fungi depend upon the algae for nutrients since they do not contain chlorophyll and cannot photosynthesize. Algae and cyanobacteria can manufacture carbohydrates with the help of light via the process of photosynthesis. By contrast, fungi do not make their own carbohydrates. Every fungus needs existing organic matter from which to obtain carbon. Fungi provide water for the algae and decompose the organic matter around them. When looked at microscopically the fungal partner is composed of filaments called hyphae. The hyphae grow by extension – branching and fusing. In lichens some of the carbohydrates produced by the algae are, of course, used by the alga but some is ‘harvested’ by the fungus.

There are 20,000 lichens on earth. They can be found growing in almost all parts of the terrestrial world, from the ice-free polar areas to the tropics, from tropical rainforests to those desert areas free of mobile sand dunes. While generally terrestrial a few aquatic lichens are known. The surfaces (substrates) on which lichens grow vary from soil, rock, wood, bone to the man-made concrete, glass, canvas, metal etc.

Amazingly, Lichens possess structures not formed by either of the partners and produce chemicals usually absent when the fungus or the alga are cultivated separately and so lichens are more than a sum of their parts. In fact, lichens synthesize over 800 substances, many of them not found elsewhere in nature. That they produce powerful antiviral properties that protect them and could be useful to humans is a fact. Why are we not studying them?

Lichens come in many sizes forms and colors. Around here some of my favorites are the bearded lichens that hang from the dying spruce down by the brook, and even in drought keep their sage gray green color. Others like the Fringed Wrinkle lichen intrigue me because they are bi –colored and so wave-like in appearance. The neatly puffed shape of Reindeer moss, (yes, it is a lichen) is another. There is a pale pink lichen that grows along my road and the crimson topped British Soldiers is yet another much appreciated lichen species.