These passages are from Oaxaca Journal, Sacks’ account of a group tour of the American Fern Society, in a part of Mexico rich with biodiversity. I love the portrait of people in love with plants. I have limited experience hanging out with expert naturalists, but in those brief times I’ve spent with them, I’ve been struck by the purity and joyfulness of their interest in the world, as though they’ve hung onto a child’s sense of wonderment.

“Finally we arrive at the Lano de las Flores. John Mickel moves about swiftly, identifying all the ferns: shield ferns, holly ferns, lady ferns, fragile ferns, bracken, sometimes fifteen feet high–all common in temperate regions. And Plecosorus speciosissimus and Pagiogyria pectinata. I love these rolling, Latinate names, redolent of a long-past scholastic age. Clubmosses, lilliputian plants out of fairyland with tiny leaves and cones, clothe the sides of the ravine. There are also many epiphytes, wreathing the trunks of trees, leaving scarcely an inch uncovered. Usually these epiphytes are harmless, clinging to the bark of trees without parasitizing or hurting them–unless the sheer weight of the epiphytes brings the tree down. (I have heard of this happening in the Australian rain forest, where staghorn ferns may weigh a monstrous five hundred pounds or more.).”

“John Mickel shows us a frond from a rare Elaphoglossum–he risked his life, apparently, crawling far out on a tree limb to get it; the tree limb cracked under his weight, almost precipitating him below. These enthusiasts think nothing of risking their lives and limbs for ferns–and they are astoundingly agile. Here is John, in his mid-sixties, leaping brooks, scrambling up cliffs, climbing trees, like a boy–and this is so for almost all the party, including some who are ten years his senior.”