Story behind the art of Nina Petrochko

Curious Allies: Mutualism in Fungi, Parasites, and Carnivores

The Fifth New York Botanical Garden Triennial

Stereocaulon saxatile on granite

Stereocaulon saxatile

Against the darkness of rocks, Stereocaulon saxatile looks like three-dimensional lace. The Stereocaulon genus ranges from polar to tropic zones. Stereocaulon saxatile, commonly referred to as rock foam or snow lichen, occurs in an Arctic to northern temperate range. This boreal ground lichen, reminiscent of coral, has a beautiful whitish gray color, with subtle hues of iceberg blue green. Its texture is a cauliflower-like granulation making up its entire surface area.

Stereocaulon species can be difficult to distinguish, which makes them a challenge to study. S. saxatile is fruticose, defined by a shrublike upper structure attached by a holdfast on substrates such as rock, tundra, moss, or other lichens. The primary thallus (or lichen body) in this specimen is disappearing. Its pseudopodetia (or stalks) have large flat thalli, branching out close to the substrate. Tiny granules called phyllocadia cover the surfaces of the pseudopodetia. The apothecia (small cup shaped structures on top of lichen that release sexually produced spores) and cephalodia (small gall-like structures found in some lichens) are rare. When dry, this lichen is hard to the touch and almost crunchy. When wet with rain, it is fluffier, flexible, and expands a little.

I first sighted this elusive specimen in Hancock County, Maine in October, 2022. It was growing in full sun on a granite outcropping at the tree line, co-occurring with crustose lichens. It was a blustery day to draw plein-air, but I managed a simple tracing paper drawing. In early December, I sat in my studio looking at the photographs I had taken, still enamored by my specimen’s beauty, and practiced rendering it with graphite on vellum to get the feel for the texture and shape. That weekend I decided to drive seven hours from Connecticut to Maine to find it again.

I contacted the Eagle Hill Institute, a research center nearby, that hosts courses on botany. The evening before my second hike, I sat by the fire with an instructor from the institute, who happened to be well-versed in lichens. He explained that the Stereocaulon I saw must have been many years old, given its texture and size (about 14 cm by 15 cm with a depth of 6-10 mm). This time it was much colder and too windy for drawing in situ. The instructor had given me some tips on how to collect a small piece of it, which I did. The rest would have to be painted from high quality photographs.

Overall, Stereocaulon saxatile has a NatureServe global ranking of G5 or Secure because it is commonly found in the world. It is not considered endangered in the United States, but in Saskatchewan, Canada it is Critically Imperiled, or S1 status. In Alberta, Canada it is Vulnerable, or S3 status. In some areas, its conservation status has not been ranked.

My painting is part of a larger series on medicinal plants for my Botanical Art & Illustration Certificate at the New York Botanical Garden. I plan to continue with the research of phytocompounds (bioactive agents found in many plant species), bringing them into focus through illustration.

Stereocaulon species have been used in folkloric medicine in Arctic and Tibetan culture, by the Cree community in Quebec, and in the Reunion Islands. In some cases, the whole lichen was crushed, air dried, and made into decoctions, teas, or ointments.

Stereocaulon saxatile is a high UV lichen which grows on a barren landscape of rocks and can produce unique secondary metabolites. One of them, lobaric acid, contains anti-inflammatory, antimicrobial, antibacterial, antifungal, and analgesic properties. Pharmacological studies have noted its cytotoxic activity against human tumor cells; however, its isolated compounds have not been applied widely in mainstream medicine.

I created my painting using a combination of wet-on-wet and dry brush watercolor on Arches hot press paper. I intended to capture the feeling of a misty day with the lichen on rock fading into space, making viewers feel like they’ve just discovered it. I used a limited palette and many subtle washes to achieve depth and texture with cool and warm grays and green-blues. The Stereocaulon saxatile is surrounded by pale green crustose lichens with tiny dark gray circles. The background depicts a granite substrate, with gray and violet washes, and a muted color moss on the left side of the main subject.

The biggest challenge with this piece was not being able to paint it from life. However, my photos provided enough details, combined with specimen samples under the microscope, to create an accurate portrayal. Much of my painting process was about preserving the negative space of the paper to make the lichen sculpturally come forward. It was a truly enjoyable and meditative piece to create.

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