I think it's an unfamiliar word to most people.
Written in kanji, it is called "Konobuki Medal Lichen."
As you can imagine from the fact that it contains the katakana character for "medal," this name was given quite recently.
As its name suggests, it is a type of lichen that often grows in round, medal-like shapes on tree trunks and other surfaces.
Many lichens are sensitive to air pollution, but this Lichen species seems to have a certain degree of resistance, which is why I think it is a species that is relatively often seen even in urban areas.
Although it is common, there are other lichens that look similar, and until I got used to it I would puzzle out, wondering "which one is which..." (I still come across some from time to time that I don't know which).
It is much larger than the candle moss that we introduced the other day, with some growing to about 10cm in diameter.
As they grow larger, the center part may peel off. The one in the photo is just 10cm long, but perhaps it was damaged by the heat, as it has peeled off in a rather pitiful way.
Normally, when it's dry, it's whitish and not very noticeable, but when it rains and gets wet, it turns a bright green, as shown in the photo below.
This is the same lichen as in the first photo, but this one was taken in June 2020. As befits its medal name, it has a round shape.
Lichens are organisms in which algae live symbiotically within fungi.
When dry, they often have a dull color, but when they absorb moisture, the green color of the algae inside becomes visible.
This year's rainy season saw little rain in the Shibuya area where our Yoyogi office is located, making it a difficult time for observing wildlife outdoors.
Rain can make life inconvenient, and flooding is a different story, but personally I look forward to the rain.
Reference: Yoshito Omura, "Urban Lichen Handbook," Bunichi Sogo Shuppan, 2016
MURAKAMI Isao