specifically argeli, a term which has no wikipedia article; mitsumata (which the article says is the name of the paper) is https://en.wikipedia.org/wiki/Edgeworthia_chrysantha. the wikipedia article says the papers are washi and, in https://en.wikipedia.org/wiki/Japanese_tissue, kitakata.

the econometrics from the article

> This year, Mr. Sherpa has hired 60 local Nepalis to help him process his harvest and expects to earn eight million Nepali rupees, or $60,000, in profit. (The average annual income in Nepal is about $1,340, according to the World Bank.) Mr. Sherpa hopes to produce 20 of the 140 tons that Nepal will be shipping to Japan. ¶ That’s a majority of the mitsumata needed to print yen ...

suggests that the total available profit is 420 thousand dollars, enough to support 313 nepalis (though perhaps the workers' wages are more than the landowner's profit, i suspect that they are, instead, smaller). the population of nepal is 30.7 million people, so this probably will not be a major new nepali export if it's just for the japanese mint. hopefully the article will make it fashionable among hipsters seeking better materials for their moleskines?

unfortunately the reporter did not think it was important to include the scientific name of the plant, so i guess we're out of luck

edit: as twic points out, it's almost certainly https://en.wikipedia.org/wiki/Edgeworthia_gardneri, so i've updated wikipedia