Limestone Barrens




We still have very little understanding of the fungi of our "Limestone Barrens".

However, during the course of the 2010 Mushroom Foray [click "DOWNLOAD" at lower edge of dark viewing area], one day was spent collecting on Burnt Cape, and a list of 31 fungus species was compiled.

Collecting Fungi on the 2010 Mushroom Foray

Collecting Fungi on Burnt Cape during the 2010 Mushroom Foray.
Photo: Roger Smith. [CLICK image to enlarge.]

Of the species on the 2010 list, the Yellow-foot Chanterelle Craterellus lutescens is known to prefer calcareous soils.

Craterellus lutescens

Yellow-foot Chanterelle Craterellus lutescens . Photo: Andrus
Voitk. [CLICK image to enlarge.]

Also of interest was the Elfin Saddle Helvella corium, which was found growing on the Cape in abundance. Elsewhere, it is usually found in gravelly disturbed ground (pathsides and the like), often in association with calcareous stone chips.

Helvella corium

Elfin Saddle Helvella corium. Photo: Andrus Voitk. [CLICK image to enlarge.]

Both of the above species were recorded only once at Burnt Cape, so they are certainly not overly common in the area.

Many fungi are "mycorrhizal", which means that their "hyphae" (underground fungal filaments) physically join onto or penetrate the roots of vascular plants, and actively exchange fluids. Because mushrooms do not have chlorophyll, they cannot make their own food, so absorbing nutrients (mostly sugars) from vascular plants is a very useful life strategy.

However, "mycorrhizal" relationships are not one-way - the extensive network of underground fungal filaments also benefits the associated vascular plant by acting as a sort of extended root system for obtaining extra moisture and mineral nutrients. On Burnt Cape, the plant partner of Lactarius "deterrimus" is Balsam Fir Abies balsamea, and the plant partner of Helvella corium appears to be the Seaside Plantain Plantago maritima.


Lactarius "deterrimus". Photo: Andrus Voitk. [CLICK image to enlarge.]

Some fungi are simply parasitic.

In summer, the rust fungus Melampsora epitea parasitizes the leaves of the Hairy Willow Salix vestita on Burnt Cape. But, rusts can have very complex life cycles, many alternating between two completely unrelated host plants, over time. In winter, Melampsora epitea parasitizes Larch Larix sp.!

The rust Melampsora epitea on the Hairy Willow Salix vestita (note the
orange spots). Photo: Andrus Voitk. [CLICK image to enlarge.]

Also on Burnt Cape, rusts of the genus Exobasidium parasitize a number of common ericaceous (ie. heath) plants - Exobasidium cassandrae on Leatherleaf Chamaedaphne calyculata, Exobasidium karstenii on Bog Rosemary Andromeda polifolia var. glaucophylla, and Exobasidium vaccinii-uliginosi on Mountain Bilberry Vaccinium ulignosum. The effect of these rusts, on their ericaceous plant hosts, can be dramatic - in the case of Exobasidium karstenii the host plant leaves become much broader and the whole plant may turn various shades of pink!

Exobasidium karstenii

The rust Exobasidium karstenii on Bog Rosemary Amdromeda polifolia var. glaucophylla.
Infected leaves are broad and pink. Photo: Andrus Voitk. [CLICK image to enlarge.]

Interestingly, the ericaceous plant hosts mentioned above actually prefer acid soils, and along with many other plants on Burnt Cape, and elsewhere on the "limestone barrens", they occur where sufficient vegetative matter has accumulated to create an acidic layer over the limestone.

Some fungi are plant decomposers. Many of these are quite plant-specific. However, few seem to specifically target limestone plants. That said, there ARE species (not yet found in Newfoundland) that decompose the limestone-dwelling Mountain Avens (Dryas sp.).

One interesting thing about fungi is that it is an important degrader of "limestone" minerals. It thus contributes to the longterm erosion of "limestone" bedrock and gravels.

[Page last updated: November 12, 2021]

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