#haematomma

[lichenaday]

Haematomma nemetzii 

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[microcosmicobservations]

If you look closely, there are at least 5 species of lichen growing on this live oak (Quercus virginiana), including a script lichen and what I’m calling  Haematomma accolens (and may or may not be wrong about). I got more than a little excited about the coastal lichen diversity in North Carolina. This was taken at Bald Head Island Conservatory.

[lichenaday]

Haematomma sorediatum

This crustose lichen grows on smooth tree bark in humid, costal and riparian habitats. It has an affinity for mild-temperate to tropical regions, and can be found in South America, Australia, India, Madeira and southern Europe. And while it is generally considered rare, this may have less to do with its actual distribution and more to do with the fact that this species is often sterile (lacks fruiting bodies (the distinctive red-disked apothecia)) making it very difficult to ID. It has a thin, pale, whitish thallus, dotted with globose soralia (openings to the middle/medullary layer where soredia are produced) or covered in diffuse soredia (small asexual propagules made of fungal hyphae wrapped around algal cells). When it is fertile, it produces small, scattered, red-disked apothecia surrounded in a sorediate margin.

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[lichenaday]

Haematomma erythromma

One of the characteristics that *typically* defines crustose lichens is their slow rate of growth compared to fungi and other similar organisms. But measuring how slow they grow is complicated. It is hard to set up a study that lasts long enough to actually measure any noticeable growth, and to control for/measure the environmental factors that contribute to their growth, or to get a sample size big enough to account for environmental variables, etc. BUT just because it is difficult doesn't mean it hasn't been done! Between 1992 and 2012, researchers measured the growth rate of H. erythromma on an Antarctic Island by marking a 25 cm sq. plot with holes at the corners, and then placing a clear plastic sheet within these corners and tracing the outline of the lichen thalli! Isn't that clever? what they found was that H. erythromma only grew 0.2 to 0.7 mm/year! Sooooo very slow--one of the slowest measured in Antarctica! It was also found that it grew in an orientation against the wind, that separate patches often grew together, and that this species often grew over the top and outcompeted faster growing crustose species! This information is vital to measuring impacts of climate change, and for the conservation of slow-growing species in this changing environment. Thank you, dedicated researchers! See their study here

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