#bacidia

Bacidia fraxinea 

This crustose lichen has a gray-green, continuous to rimose-areolate (cracked and tile-like) thallus that grows on the nutrient-rich of deciduous trees (particularly those of the Fraxinus variety). It has bulbous, salmon to orange-brown apothecia which produce long, needle like spores. You can find B. fraxinea in mild-temperate habitats in Europe, though records of it are sparse. More work is needed to fully separate records of this species that are likely confused with its more common look-alike, B. rubella.

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Bacidia schweinitzii 

Bacidia bagliettoana (syn. Toniniopsis bagliettoana)

Bacidia arceutina

So I talk about apothecia a lot, but what exactly are apothecia? They are the fruiting bodies of the fungal constituent of lichens. They produce spores in internal sac-like structures called asci (singular ascus), and are typically cup, disc, or dome shaped. B. arceutina here has pale brown to brown-black apothecia which have a concolorous margin (the ridge surrounding the disk) and a flat disc when young, but become for bulbous and dome-shaped with age, often losing the marginal edge. Here is a cross section of a B. arceutina apothecium:

See all those little tube-y structures near the top? Those are the asci, and they are full of long, linear spores that look like this:

Spores like this aren't typical for all lichens, but are for lichens in the Bacidia genus.

I love them. So strange. These spores are sexually produced and ONLY contain the genetic material for the fungal constituent of the lichen, and not the photobiont constituent. So these microscopic spores, when dispersed, have to form a partnership with a Chlorphycea algae (one of my faves, TBH) if it wants to grow and thrive. So good luck out there, you tiny, wormy B. arceutina spores! I hope you can find purchase and partnership on the nutrient-rich, basic bark of trees and shrubs you prefer.

images: source | source | source | source

Bellicidia incompta (syn. Bacidia incompta)

Sap groove lichen

This lichen forms a granular or mealy crust of pale gray, green, or fawn in the wonded and sap-tracked areas of elm trees in Eurasia, with smaller populations in Tunisia and North America. Currently, European elm populations are being absolutly desimated by Dutch elm disease--caused another, less friendly fungus, Ophiostoma novo-ulmi. Fewer elms means fewer species that rely on elms for survival, such as B. incompta. In a lot of ways, that’s just how the system of natural selection works, but that doesn’t mean we have to feel nothing about it, or that we shouldn’t investigate what is happening and figure out our part in it, and mitigate the destruction where possible. All those things can exist at once and that’s just what it means to live on this planet. 

Bacidia rubella

Frosty-rimmed dot lichen

Can I still say squee? Or is that like, so 2009 of me? Cause I really wanna squee over this lichen! Oh god, 2009 was 11 years ago. Existential crisis time. I’m fine. Anyway, B. rubella is a crustose lichen with a granular thallus (meaning that is looks like little grains of sand stuck to the substrate) with numerous granular isidia. The upper surface color is greenish gray to yellowish green, and dotted with numerous red-hued apothecia. I think the apothecia look like the red blood cells from that episode of Magic School Bus where they go inside Ralphie’s body while he’s sick, but I’m getting off topic. B. rubella grows on nutrient-rich bark, and has been recorded in North America and Europe. This lichen does not fair well with pollution, and so is often found on mature trees in sheltered forests. Guys, I can’t get over how cute he is. If I encounter B. rubella in the wild I will definitely, like, totally flip out. Yep, showing my age again. Don’t mind me.