Lichen, a Curious Fungi & Plant Composite….
By Gordon Patterson
The diversity of vegetation in British Columbia’s rainforests and woodlands is extraordinary, particularly within the cool, humid coastal forests of North Vancouver Island. During the snow-free seasons, hikers such as Christine Rosie and I are welcomed by a world of lush foliage, where leaves, fronds, and woodland plants display an astonishing variety of shapes, textures, and patterns. They grow beneath and around towering western hemlocks, cedars, balsam, alders, and cottonwoods, creating a richly layered forest alive with colour and wildlife, to the enjoyment of many.
Shades of green range from soft, soothing pastels to deep, vibrant hues, mingling with the warm browns of tree bark, fallen branches, and a textured forest floor. Among this abundance are curious plant-like organisms known as lichens, complex life forms that are still not fully understood. Lichenologists continue to document many new forms, unique relationships, and roles of lichens within the forest’s macro- and microscopic worlds. Far more than mere reindeer food, these fascinating organisms are a captivating part of British Columbia’s and Canada’s forest ecosystems, and foundational organisms essential to several of the world’s most extreme or sensitive environments, most notably Arctic regions , alpine tundra, European boreal forests (taiga), and arid deserts. Lichen have a world ecological influence.
Interesting eh!
Recognizing Lichen
Pacific Northwest lichens are perhaps most recognizable as delicate ribbons of pale green hanging from the branches of conifers and deciduous trees, swaying gently in the breeze. Elsewhere, small, pale-grey, apple-sized spheres of tangled, thread-like growth cling to the bark, while leafy, lettuce-like forms spread across branches and rocks. Lichens are more than intriguing curiosities: they provide shelter and food for tiny organisms, contribute to nutrient cycling as they break down rock and organic matter, and help create the conditions needed for other life to flourish. Their sensitivity to changes in air quality and habitat also makes them valuable indicators of a healthy, intact ecosystem. I find them especially fascinating when they colonize ancient stones, where their slow growth can produce living traces of landscapes that have existed for centuries.
Whatever these intricate organisms are, they stimulate your imagination by unique fragile beauty that draws one to look closer. Scientists have documented over twenty-five hundred different types of lichen across Canada, and many more are yet to be studied and identified!
Lichen Structure
But what exactly are these delicate multidimensional organisms? Do they have mythical origins referred to as Witches Hair, Reindeer Food, Old Man’s Beard, Mary’s Tears, Fairy Cups, etc. Are they plants, fungi, or other type of entity? How old are they, how do they grow, what is their role in forest ecosystems…… so many questions?
Fairy Cup lichen and other species like reindeer lichen contain didymic acid, and they were once used by herbalists to treat tuberculosis. They are called fairy cups because they are said to resemble the tiny cups that pixies or wood fairies sip morning dew from.
The short answer is lichen are not solely a fungi nor a plant! They are a composite of both… The organism consists of a fungal supporting latticework called a thallus, made up of fibres called hyphae. This thallus provides a home for either a partnering algae or cyanobacterium. Together they marry into a symbiotic relationship creating a mutual dependency on each other for food and life sustaining needs.
The Fungal Partner Determines Lichen Shape
The type of fungi determines the organism’s shape…. as well as determining what kind of rhizine rootlike structure (usually) to attach on substrates: branches, bark, soil or rock. Lichen by itself do not harm their forest host. If a tree dies, it is usually caused by another organism! In fact some lichen actually insulate their hosts from environmental temperature and pollution challenges. Interesting stuff eh!
The fungus rootlike cortex sources water and mineral necessities, for itself and partnering algae or cyanobacterium. Through a photosynthetic ability, provides bioenergy to the collective. The fungal species determines the scientific name assigned to the particular lichen.
Primary Lichen Classification
Lichens are interestingly classified “by shape” into three basic types:
- Crustose…. Flat crusty looking one dimensional entity pressed on a rock or other substrate
- Foliose… Leafy looking two dimensional structures
- Fruticose… Shrubbery stringy three dimensional organisms
There are other sub classifications having a mix or other unique features of traditional classification shapes
- Squamulose, having small, scale-like plates that often overlap like shingles, an intermediate form between crustose and foliose.
- Leprose, powdery lichens that lack a structured outer layer
- Jelly Lichens, becoming jelly-like when wet because they contain a large amount of certain cyanobacteria which swell with water.
- Placodioid, a specialized crustose form where the edges are lobed and slightly raised
It is a complex continuously evolving field
Finding Lichen
I have wonderful memories walking amongst carpets of Arctic lichen, watching caribou graze on this choice tundra flora…. The organism is an essential food staple for the constantly moving masses of migrating caribou. Many other Arctic inhabitants, such as hares, muskox, lemmings, geese enjoy its culinary benefits. Fortunately the slow growing tundra lichen are remarkable survivors of short growing seasons withstanding tremendous fluctuations in temperature. In turn, many Northern wildlife species are dependent on lichen tenacity as a nutrient source aiding their survival.
In British Columbia lichen are noticeably abundant in exposed alpine topography, coastal marine areas, cool rainforests, and boreal regions. Their mineral rich composite structures are equally an important staple food source for many BC herbivores during harsh winters; moose, elk, caribou, deer, birds, rodents…. Many forest inhabitants, such as hummingbirds, hawks, owls, and squirrels, also makes use of lichen as soft, warm insulating nesting material.
Interesting Lungwort Lichen is a symbiotic relationship between three entities: a fungus, a green algal partner, and a cyanobacterium, involving members of three biological kingdoms! It is very sensitive to air pollution and a healthy presence is considered an indicator of an unpolluted ecosystem. It is found in mature, or old-growth forests. Lungwort has been used as a source of dye, and in traditional herbal medicine to treat ailments like lung diseases and asthma. Some brew it as a tea.
Lichen Benefits
Although they are often overlooked, lichens provide several intriguing and potentially valuable benefits to humanity. Their importance is especially evident in discussions about climate change and environmental monitoring. Through their unique biological structures, lichens can absorb and retain carbon, nutrients, and certain pollutants from the atmosphere. This capacity allows them to contribute to natural carbon cycling while also serving as sensitive indicators of air quality and environmental disturbance.
Lichens have also attracted interest for their possible medicinal properties. Some species contain complex organic compounds that may possess antimicrobial or anti-inflammatory effects. For example, Old Man’s Beard (Usnea) has traditionally been associated with compounds believed to help combat infection-causing microorganisms, soothe coughs, and support wound healing. It has also been linked to claims involving pain relief, inflammation, and weight management. However, experts warn these potential health benefits should be treated cautiously: there is currently insufficient scientific evidence to support the routine medical use of Usnea or other lichen-based remedies. Further research is needed to determine their safety, effectiveness, and appropriate applications.
The Wolf Lichen pictured here is deserving of mention in that it is toxic to carnivores, and some first peoples used it to poison arrowheads. It’s rich in vulpinic acid, which is bright yellow and gives Wolf Lichen it’s colour. The name comes from a past European practice of using the lichen to poison wolves. The vulpinic acid is toxic to meat-eating mammals. It is not toxic other mammals, and like most lichens it is eaten by deer and elk with no ill effects. Scientists believe only a small number of lichens are poisonous, the wolf lichen being a readily identifiable by its bright yellow colour. It is extremely resilient and when conditions are right can survive for many centuries.
Observers often associate lichen with old, decaying or dead trees and assume that a trees demise was caused by the lichen. However, many lichen tend to appear on trees that are already in decline.
Lichen Age
Lichens can be extremely long-lived, some are considered to be among the oldest living things on earth. Their longevity is a subject of ongoing study, and some Pacific Northwest rainforest lichen such as the specklebelly lichen may live as long as their tree host. Some Map Lichen found in the Arctic may be thousands of years old. Some Antarctic lichens too have estimated ages of a few thousand years! Lichens pictured here such as Rock Lichen grow very slowly, some taking twenty-five years to grow 1 cm. Others such as Methusula’s Beard can add metres to hanging ribbons over the course of a season. Lungwort lichen grows slowly about “4 mm” annually! Imagine the age of the Lungwort pictured in this article… perhaps decades old!
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When the hike is finished and woodstove lit, I enjoy sitting back reflecting on the rewards of the day’s adventure; thoughts on what we heard and saw…. And Lichen, in all its quiet complexity is remarkable composite organism to find, woven into our memory from fungi, algae, and sometimes cyanobacteria. It stands as one of nature’s most adaptable partnerships and enriches every ecosystem it touches. This amazing entity sequesters carbon, softens harsh landscapes, and adds subtle beauty to bark, stone, and the forest floor. Its presence, whether deep in woodlands or the heart of a city, serves as a living barometer of air quality and environmental well‑being.
Beyond ecology, lichens have long supported wildlife with food and shelter, and have shaped human cultures throughout the world with traditional medicines, dyes, and practical uses passed down through generations of peoples. The entities survival in the harshest of wind, frost, and drought reminds me that tenacious ability often appears in the smallest forms, without banners and fanfare.
In the end, lichen is a wonderful example nature’s quiet flexibility, an ancient partnership metaphorically we can learn from…. Strengthening each other to thrive in places most life would falter. To notice lichen is to appreciate a deeper story of the forest: one that draws you in to observe patience, adaptation, and the subtle threads that hold the wild Kingdom together.
Isn’t Nature Grand!
Safe Travels,
Gord
Gordon F. W. Patterson
Photos © 2024 Christine Patterson