Crater Lake seems to be an especially favorable locality for the bizarre and unusual plant life. Besides the seven new species that Colville found in this region in 1896, he has since described another. (In Underw. Nat. Ferns ed. 669, 1900). This is a little fern that grows only on the highest pumice slopes. It really is not a true fern since the fronds are not circinate in the bud, the sporangia do not have typical fern's annulus, and the spores are formed within the tissue of the sporophyll. By these characteristics we place it in the Adder's Tongue Family (Opheoglossaceae) but still for all practical purposes we may call it a fern.

Its extreme rarity is evidenced by the fact that it has been found by collectors only twice. The type specimen was found a good many years ago, but since then it has "hidden out" on us completely, with the single exception of a specimen which was collected this season.

Not only its rarity, but also its protective coloration aids it in escaping notice. The leaves, or fronds, are a dull grey color, which blends perfectly with the pumice slopes on which it grows. This is a fortunate circumstance, since it would soon become extinct were it at all conspicuous.

Botanists call this plant Botrychium pumicola, which altho grammatically incorrect as Latin names go, means "pumice inhabitant."