Exsudoporus frostii

Exsudoporus frostii, the Frost’s bolete or apple bolete, is a fascinating fungus that has intrigued mycologists and mushroom enthusiasts alike. First described in 1874, this species has a rich history and unique characteristics that make it stand out among its bolete relatives.

Identification and Distribution

How can you spot Exsudoporus frostii in the wild? Well, if you’re looking for a mushroom with dark red sticky caps and red pores, this is your guy. Found from Maine to Georgia, westward into Tennessee and Michigan, and even in southern Arizona, Frost’s bolete thrives near hardwood trees, especially oaks. Its distribution spans across the eastern United States and parts of Mexico and Costa Rica.

Distinctive Features

The cap of Exsudoporus frostii is a tell-tale sign—dark red when young, fading to pale yellow or lemon yellow as it matures. The flesh underneath can be quite thick, ranging from 2.5 cm to over 2.5 cm in thickness. When you bruise the mushroom, look out for those blue stains—it’s one of its key identifiers.

The stipe is long and thick, with a red or yellowish surface near the base. The pore surface is a bit more complex—yellow to olivaceous yellow, with small circular pores that turn dingy blue when bruised. This beaded appearance can help you distinguish it from other boletes.

But wait, there’s more! The spore print of this mushroom is olive brown, and the spores are thick-walled, smooth, spindle-shaped. These features make for a unique combination that sets Exsudoporus frostii apart in the mycological world.

A Bit of History

Charles Christopher Frost, a botanist who published a description of this species in 1874, gave it its name. Over time, the genus has undergone changes, with Exsudoporus being the current home for this fascinating fungus.

Edibility and Safety

Is Frost’s bolete safe to eat? While usually viewed with suspicion due to its red hymenium, it is generally not recommended for consumption. The risk of confusion with other poisonous boletes makes it a mushroom best left untouched in the kitchen.

The taste and odor are described as ‘pleasant’ or ‘sweet,’ similar to citrus. However, chemical analysis shows that the fruit bodies have a composition rich in moisture, ash, dietary fiber, fat, protein, and free fatty acids. Oleic acid is the majority component, making it a nutritious but potentially risky addition to your meal.

Ecological Role

Exsudoporus frostii plays an important role as a mycorrhizal species, forming associations with various tree species like Virginia pine and oak. It grows solitarily or in groups under hardwood trees, fruiting from summer to early autumn.

Parasites and Associations

The fruit bodies can be parasitized by Sepedonium ampullosporum, causing necrosis and a yellow color due to aleurioconidia formation. This interaction adds another layer of complexity to the life cycle of this fascinating fungus.

Conclusion

In conclusion, Exsudoporus frostii is a unique and intriguing species that continues to captivate mycologists with its distinctive features and ecological role. While it may not be on your dinner table anytime soon, understanding this bolete can deepen your appreciation for the diverse world of fungi.