This is the tips document for USID Lichen Guide found at The purpose of the guide is to stimulate interest in documenting the lichens of Idaho. Please consider reporting and uploading images of your identifications on the site as you identify them. USID Lichen Guide is a guide and not a scientific key to lichen identification. If you are looking for a scientific key I recommend Lichens of North America. The guide is designed for users with an interest in plant identification.

The guide is still under development but far enough along it is usable for most lichens found in Idaho and counties adjacent to Idaho. It also includes species found in Glacier, Tetons and Yellow Stone National Parks. A few species have not been included in the guide because a good description was not found or not available without charge. The guide does not include a few unique parasitic lichens nor varieties and sub-species with limited Idaho collections. If you find a characteristic that should be added to aid identification or a missing species found in Idaho please contact me ( ). I am planning to add more images as time and travel permits.

If you are experiencing time out errors using servers at University of Georgia consider switching to another server listed at the bottom of the DiscoverLife home page. Universities are experiencing heavy internet traffic from anonymous hackers. I typically use the Original or Missouri Botanical Garden as an alternate server.

Lichen Basics

Lichens are the marriage of a fungus with a photosynthetic partner (algae or cyanobacteria). The partnership form unique structure, physiology and chemistry. Lichens lack roots and are not parasites. They take advantage of a substrate for sun and protection. Many lichens may live +900 years. Taxonomically, we are wealthy with almost 1,000 lichen species found in Idaho. They are an ecosystem scorecard where a count of species indicate the quality of health. They are an important tool for estimating the age of an exposed rock.

How to collect specimens

Lichens are collectible year round but May to October is the best time for full development of both sexual and asexual structures. You may need to visit the field site a couple of times to determine optimum timing. Fallen branches appear to be a great source for specimens but often the identification is difficult because the photosynthetic partner maybe dying. If the photosynthetic partner has died the lichen will appear bleached and apothecia are often missing making the specimen difficult to identify.

National Parks including Historic Sites and Monuments and many State Parks do not allow sample collection but imaging is always permitted. Avoid collecting samples in high use sites such as picnic areas and trail heads. Always ask permission before collecting samples on private property. My favorite sites in Idaho are "rails to trail" bike paths, cemeteries, old road cuts and fence posts, public fishing and hunting access sites and county parks.

I have stopped collecting herbarium quality specimens using the card and paper packet system and now take a digital approach. It embraces new technology, improved internet access and the need to conserve space. Many herbaria are downsizing and digitizing specimens to conserve space and improving internet access to their collection. If you are collecting for a herbarium contact the director to conform with their standards.

My collection methods use digital images plus a small representative sample that fits into a 2 x 2 inch pocket of a vinyl coin flip. See Macro Photography for digital imaging hints.

After the images are made with the camera a small sample is removed from the substrate and placed in the flip pocket. A long sheet rock screw or large straightened paperclip used as a pick or scraper will aid in removing lichens from the substrate. A few drops of water will often loosen the lichen sufficiently to easily remove a fragment. The sample should be a fragment and not the whole lichen. Sample fragments are often easier to chemically spot test and identify specific features. A flat toothpick will help to place fragments in the vinyl pocket. Take the time to record notes for each lichen packet!!! It is tempting to collect lots of lichens at a site but it is better to collect a few unique specimens with good photos and notes. Notes to record for each lichen include location (lat/long from gps) and date with optional information such as surface color and substrate. Finally take an image of the completed packet placed next to the site where it was removed before moving to the next lichen.

The flips are used by coin collectors and stored in 2 x 2 inch slide pages and a 3 ring binder. Before going to the field add a piece of card stock to one pocket for notes and a flat toothpick to the other pocket to aid drying and help with sample placement. The vinyl flip allows two sided identification and a big advantage over the old card and paper packet system that I used for many years. Vinyl coin flips are 100 for $7-8 and pages are 20 for $5-6 from a store specializing in coin collecting or Bulk orders will reduce costs. The flips are easy to keep organized.

Download images to computer and tag images with the location. I group my images in a directory to be identified by year and month. Once the lichen has been identified add the name to the title of the image under properties then add location to the tag box. Move the identified lichen images to identified directory and sub-directory under genus name. Upload identified images to

Using the Guide

Start with the three main menus. If you are not sure select the Explain or select the picture for further explanation. Leave blank or select multiple boxes when in doubt. Select additional criteria using simplify (in the upper left) and search for additional features. The guide can be used on any device with internet access. If the guide does not have an image and comes up select "See original" and select Google Images or check to see if it is posted there.

If you go down a path that does not result in a good match try checking more habitat or microclimate possibilities or color ranges. Literature may report habitat as found on soil or rock but it is occasionally found on bark and wood.

Some specimens will not be identifiable because something is missing from the image or notes. A second collection may be necessary when sexual or asexual structures are present and record missing data in notes.

Chemical spot test

Simple chemical spot tests have been used as a identification aid for over 100 years. Three common tests are included for the guide. Most of the time the spot test is not necessary to identify Idaho taxa, but will aid when stumped. Potassium hydroxide (10% KOH solution) will cause a color spot on 25% of the lichens found in Idaho. Clorox bleach (Chlorine) will produce a color spot on 15% of Idaho's lichens. KOH test followed by Clorox test produce a color spot on less than 5% of the lichens found in Idaho. Potassium hydroxide, a strong base, is used for soap making. Small quantities of KOH may be available at a food coop or at A 15 ml bottle of 10% potassium hydroxide will last for several years if you use a flat toothpick to apply. Chlorine will need to be refreshed weekly but KOH is stable for many years. I use a spa chemical test strip to check activity of chemicals when in doubt.

Remove a small piece of lichen exposing the medulla (middle layer of lichen) with a razor blade or finger nail trimmer and place on a piece of paper. A small dab of glue from a glue stick or hot glue gun will help hold the lichen fragment in place. Use the point of a flat toothpick to apply the test solution to the cortex (lichen surface) and medulla then monitor the color change with hand-lens for 60 seconds. The flat toothpick will produce a dot about the size of this o. The test solution usually causes the spot to change instantly but second color shift may take a minute to develop. Record results on the note card in the sample pocket and discard tested sample.

The lichen guide includes long-wave UV fluorescence test results. A long-wave UV light will cause 4% of Idaho lichens to fluoresce. The test should use a long wave UV light source in a darkened room. Battery operated UV flashlight are available from Amazon or a store specializing in mineral exploration or gas leak detection. A good UV flashlight is a brighter light source. The UV flashlight plus UV safety glasses will cost between $25 to $50. I have tried a hand lens with a UV light source. I liked the idea for field viewing but the switch was defective after a few uses. Professional UV viewing cabinets reduce the need for a darkened room but they are expensive ($545 from VWR). Most of the time UV tests will not aid in identification and used more as a proof positive the specimen is correctly identified.

Scientific identification may require the use of thin layer chromatography (TLC). TLC supplies are not readily available and the procedure is complex. The lichen guide reduces the need for TLC by focusing on species found in Idaho but does not replace the value of TLC. If you are scientifically identifying lichens consider purchasing the TLC equipment and solvents necessary to use the key found in Lichens of North America.

Microscope for identifying lichens

The guide was written so you could use a good macro image an a hand lens for identification. I found the addition of a stereo scope enhances the view of detailed characteristics of the collected samples. I use a AMscope 7x-45x trinocular scope on a single arm boom stand. The light source is an 80 LED compact ring with built in dimmer. The optics are good and produce a clear view of the specimen. I am impressed with the weight of the base and balance of the arm. I have set the horizontal arm at a fixed distance. It is simple pivot the scope over your work area using vertical arms for adjustments. The scope needs to be refocused when changing magnification but that is true with research grade scopes. I bought a 2X Barlow lens but have not used it since 7 to 45X meets my needs. The 7x has a 4 mm field of view and 45x has a field of view of 1 mm. I have not tried to mount a camera on the third ocular. The view from the left eye ocular is diverted to the camera with a push-pull knob. Seems simple enough. I have found the quality to be better than scopes used for my college classes. The scope works for my lichen and moss identification needs and the price was right.