Introduction
Unfortunately, my recent research strongly seems to imply that
Physciella chloantha can only grow several millimeters each year even under extremely frequent hydration; fortunately, since "adult"
chloantha thalli are naturally rather small this means that under such a growth rate there will in fact be a significant proportional increase in their size after several years. Unfortunately, it is still a rather slow growth rate, although at least it is faster than that of many non-synanthropic lichens.
Fortunately, some lichens still grow much faster than
chloantha. These include the "obligately" foliicolous ephemerals (more on that later), but also some larger-bodied types such as
Peltigera and
Herpothallon (sidenote:
Peltigera is one of the few lichens that have successfully been grown as a non-axenic whole thallus indoors;
Moss Grower's Handbook reports that it pops up occasionally in cultivated moss setups as a very minor pest).
Death and tax(onomi)es
Hazel of
Hazel's Science Things has been generous enough to supply me with a number of lichens freshly imported from Florida and Ohio, and among the most notable is the red and mint-green thing pictured above and below (interestingly it stays green even when dry):
 |
| the pointy things are true mosses |
This is, um, er..., perhaps a specimen of
Herpothallon rubrocinctum. "My" reference book
Lichens of North America states that
H. rubrocinctum is completely unmistakeable; I am not sure whether it means "no other species with identical appearance exists in NA" though. Furthermore, the cryptogam specialist I had been sending my specimens to lost all confidence in redstriped
Herpothallon ID after I found a dichotomous key and an unrelated image implying that
H. globosum was red and stripy; another lichen person the first one called in was similarly terrified.
I am currently waiting for a third opinion on the matter.
Herpothallon rubrocinctum: an ecological overview
Available evidence gives me the strong impression that any possibly-confusable species are only other
Herpothallon; thus, they have some probability of being ecologically similar.
Information on
rubrocinctum habitat appears to be surprisingly sparse in the scientific research literature; it seems to be one of the poster children of lichenworld, presumably due to its bright coloration, and is frequently mentioned on nature sites targeting non-researchers. Other lichenized members of the Arthoniaceae are normally drab in color, barely recognizable as lichens or even live organisms to the untrained eye, and receive essentially no attention from anyone at all; they appear to be equivalent to the tiny brown beetles and parasitoid wasps which tormented entomologists mention using phrases like "hostplant unknown" and "genus revision desperately needed; multiple undescribed cryptic spp. present". Ironically, I do not perceive
rubrocinctum as beautiful in coloration; since color-based attractiveness seems to be controlled by modifiable instincts (perhaps the fruit-seeking ones? I'm not a psychologist) and is apparently not an inherent/objective property of objects, I appear to have accidentally trained my subconscious mind to associate only muted color palettes with prettiness. Spending massive quantities of time looking at drab tenebrionid/carabid beetles has some bizarre side effects, I guess! (Not that I care either way, since I am mostly just interested in extracting science from the thalli.)
After a brute-force scan of every
rubrocinctum paper in existence(!) on Google Scholar, I have assembled a tentative map of its preferences:
- Colonized substrate known to include a wide variety of native and non-native bark/mosses (the pictured thallus is in fact smothering the mosses to death), but also rarely rock and angiosperm leaves; I imagine it is theoretically capable of colonizing plastic, like many other foliicolous lichens. (NOTE: I have previously suggested that
Physciella chloantha may also be plastic-colonizing due to its ability to grow on top of mosses; however, since I have never seen reports of it growing on angiosperm leaves or plastic in the wild, and it seems intolerant of extreme smoothness, if it can grow on plastic special conditions are likely needed to help it hydrate and attach properly.)
- It is widespread throughout the humid tropics, although it may rarely also occur in the dry zones of such areas; one paper reported it was present even on several environmentally degraded farmland areas.
Another reported that it was extremely water-repellent, likely to prevent drowning during heavy rains. An illustration within mentioned that the exposed thallus surface is superhydrophobic; conversely, the side in contact with the bark is riddled with a complex network of channels to collect and rapidly drain water. My own observations confirm the repellence; specimens appear to dry out quite quickly even compared to other lichens despite thorough spraying. Finally, a third paper mentions that Floridian specimens it studied had constant 24-hr access to water except for a few hours at noon; I will try to keep my specimens constantly sprayed whenever the sun is active (lichens can't photosynthesize in darkness anyways, so inducing nighttime dormancy should probably save energy).
- A few papers mention that it has been found on acid bark, although I could not find if it prefers acidity or merely tolerates it; I did not see any reports mentioning its presence on neutral or calcareous substrates. Hazel reports that the hostplant of the ones sent to me is
Quercus (oak), which is indeed acidic unless it has been calcified by aerial dusts. To be safe I will be watering it and all the other Florida lichens (the local region apparently has acidic rain) with distilled mineral-free water; if what a paper told me about bark pH is correct, then the bark acids will acidify neutral water applied to it.
Unrelated bonus paper
https://www.researchgate.net/publication/231794852_A_new_species_of_Arthonia_is_a_pest_in_an_orchid_nursery
As mentioned above, many
Arthonia (including this one) are nondescript mold-like films. Do note that in the back it mentions several other lichens naturally occurring or successfully cultivated in greenhouses.
