Botany Photo of the Day

Updated February 7, 2006 at 4:06pm: Thanks to Doug who suggested some alternatives to my tentative identification in the comments, I went out and re-examined the lichen. I'm now reasonably confident that this is Evernia prunastri and not what I misidentified it as, Platismatia stenophylla. I think it's an opportune time to remind you that I'm more interested in having the correct information available to BPotD readers than I am in being “right”. If I ever post something that doesn't sit right with you or if you can add something (including a different perspective!), please comment – Daniel.

Mysteries abound, today. Let's start with the lichen. I'm fairly certain it is Platismatia stenophylla or ribbon rag lichen, but it's difficult to confirm. I've only one image in a book to compare with, since there are no results in image search engines for either Platismatia stenophylla or a synonym, Cetraria stenophylla. Nope, I was wrong – Evernia prunastri is a better match. This taxon's native range of occurring in coastal forests of temperate western North America matches, as does its property of growing on trees – so perhaps I'm right. To help be certain, I'd have to break out the chemistry kit. As I've noted before, lichen identification is often aided by observing reactions to chemical reagents (if you ever see a person in a forest with a satchel of small bottles covered by eyedroppers, you will have encountered a bona fide lichenologist).

For Platismatia stenophylla Evernia prunastri, confirming that it is either KC+ (yellowish) or KC- would help verify my tentative identification. This test would involve first wetting the thallus (body) of the lichen with a ten percent potassium hydroxide (KOH) solution, or the K test. The C test would be a dose of bleach, that is, a solution of sodium hypochlorite. If there is no apparent reaction to the bleach on the KOH-soaked lichen, another bit of evidence would be in agreement with the identification. If the test was positive, however, the thallus would change colour. For this lichen, a change to a yellowish colour would help confirm. If it changed a different colour, I'd be back to scratching my head over other possibilities.

The Oregon Coalition of Interdisciplinary Databases has a good entry on Evernia prunastri, and image search comparisons also suggest a match.

The hybrid witchhazel poses a different sort of mystery. Occasionally in the past few years, some staff time has been invested in attempting to verify that a cultivar 'Fireglow' exists. So far, we've come up short. Staff from the garden have searched online, reviewed the horticultural literature and even contacted the International Cultivar Registration Authority for Hamamelis, all to no avail. Its existence as a cultivar could be due to something as simple as a clerical error in its thirty year history. Or, perhaps it is a locally-developed selection, named and sold only to a select few three decades ago (it was purchased from a now-closed local nursery). Too, it could be a misidentification and actually an entirely different cultivar. We haven't yet figured it out.

Photography resource link: Tripod Therapy, an article by Rod Barbee for Nature Photographers Online. Good advice regarding one of photography's most important tools.