Preserving mushroom specimens involves a series of careful steps designed to maintain their physical characteristics and scientific value over time. This process is essential for detailed study, accurate identification, and the creation of lasting mycological collections.
Why Preserve Mushroom Specimens?
Preserving mushroom specimens serves multiple purposes. For scientific study, preserved specimens provide a physical record for taxonomic analysis, allowing mycologists to compare features across different collections and refine species classifications. This physical evidence is also valuable for educational purposes, enabling students and the public to observe fungal diversity firsthand. Preserving mushrooms allows for the creation of personal reference libraries, aiding in the identification of future finds.
Essential Preparation Before Preservation
Careful preparation immediately after collection is important for successful mushroom preservation. Begin by gently cleaning the specimen, removing any soil, debris, or insects with a soft brush or damp cloth. Avoid washing mushrooms under running water, as they can absorb moisture, which complicates the drying process.
Documenting the mushroom’s original appearance and environment is also important. Take detailed photographs from various angles, capturing features like cap shape, gill attachment, stem characteristics, and overall color. Record essential data such as the date, exact location including geographical coordinates, habitat type, and the substrate on which the mushroom was growing. Make initial observations on features like odor, texture, and any color changes when bruised or cut, as these can be lost during preservation.
Common Preservation Methods
Drying is the most common and effective method for preserving most mushroom specimens, as it removes moisture and prevents decay. For many fungi, an electric food dehydrator offers a consistent and efficient drying environment, typically operating between 125°F and 135°F (52°C and 57°C). Mushrooms should be sliced thinly, about 1/4 inch thick, and arranged in a single layer on the dehydrator trays, ensuring good airflow. Drying times can vary significantly, ranging from 4 to 12 hours depending on mushroom type, thickness, and dehydrator settings.
Alternatively, an oven set to its lowest temperature, generally around 140°F to 150°F (60°C to 65°C), with the door slightly ajar, can also be used. This method requires careful monitoring, with drying taking approximately 2 to 6 hours or more. The goal is for the mushrooms to be thoroughly dry and leathery, not brittle.
While drying is preferred for most specimens, liquid preservation methods are sometimes employed, particularly for fleshy or gelatinous fungi that do not dry well. Solutions like 10% formalin (a formaldehyde solution) or 70% ethanol can be used to preserve specimens. Formalin effectively fixes tissues, maintaining their structure, while alcohol primarily acts as a preservative. These methods typically involve submerging the specimen entirely in the liquid, often after injecting the solution into larger specimens to ensure thorough penetration. However, liquid preservation can alter natural colors and textures, and it requires careful handling due to the nature of the chemicals involved.
Creating a Spore Print
Creating a spore print provides a crucial diagnostic feature for mushroom identification. This involves placing the cap of a mature mushroom, gill-side down, onto a piece of paper that contrasts with the expected spore color. Using both dark and light paper can be beneficial for capturing the print, as spore colors can range from white to black, or various shades of brown, pink, and purple. Cover the mushroom cap with a bowl or cup to prevent air currents from disturbing the falling spores and to maintain humidity, which encourages spore release. Allow the cap to sit undisturbed for several hours, ideally overnight, to ensure a clear print forms.
The resulting powdery deposit reveals the mass color of the mushroom’s spores, which is a key characteristic used in mycological guidebooks for narrowing down species. While a spore print alone cannot definitively identify a mushroom, its color can immediately rule out many look-alike species, making it an invaluable step in the identification process. This technique complements the physical preservation of the specimen, offering additional data that remains stable over time.
Labeling and Long-Term Storage
Proper labeling ensures that each specimen retains its scientific value. Each preserved mushroom should be accompanied by a durable, detailed label that includes the species name if known, the date of collection, the precise location (including GPS coordinates), the collector’s name, and any relevant ecological notes such as habitat or substrate. This information allows future researchers to understand the specimen’s context and verify its identity. Without accurate data, a preserved specimen loses much of its scientific utility.
For long-term storage, preserved mushroom specimens, particularly dried ones, require specific conditions to prevent degradation. Store dried specimens in airtight containers, such as glass jars or sealed plastic bags, to protect them from moisture and pests. These containers should then be kept in a cool, dark, and dry environment, as light can cause color fading and fluctuating temperatures or high humidity can lead to moisture reabsorption and mold growth. Protection from insect pests is also important, often achieved by including silica gel packets to absorb any residual moisture or by periodically checking specimens for signs of infestation. Proper storage ensures the longevity and integrity of the collection.