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Excerpts from Jim Conrad's
Naturalist Newsletter

Entry dated April 19, 2024, from notes taken about 1.5km northeast of Puerto de los Velazquez, Municipality of Pinal de Amoles; N21.138°, W99.665°, elevation ~2780 meters (~9120 feet); oak/pine forest on limestone bedrock; in the Eastern Sierra Madre Mountains of east-central Querétaro state, MÉXICO
HEMIONITIES [ALEURITOPTERIS] FARINOSA

Rooted in shattered rock associated with a a geological fault through limestone on the mountain's northern slope, the above fern sheltered on the face of a relatively moist, shady roadcut. The fault zone's crumbly rock afforded easier downward passage of rainwater than through unfractured rock, and several species took advantage of the water's special availability. However, the above fern is very dried out, possibly dead. The North American Drought Monitor designates this area as experiencing their droughtiest of drought categories, the D4.

Above, despite its parched-brown state, the frond's undersurface displays the kind of white surface botanists describe as farinose -- covered with a whitish, mealy powder. The blade's black midrib, or rachis, and the secondary veins off the rachis, the costae, provide a striking, even elegant, contrast against the white surface.

Above, the mealy nature of the farinose surface is more apparent. Note that the main stem, the rachis, is furrowed, or channeled. Margins of the frond's ultimate lobes, the pinnules, curve under, forming "false indusia," which strongly suggests that we have yet another species of the big lipfern genus, Hemionitis. However, as best seen in the picture's lower, right corner, the margin also bears several flat lobes, similar to one side of a short zipper. The false indusia are "interrupted," creating a toothed or "crenate" effect. I've not seen such a thing among the lipferns, or any other taxa.

Above, a brown-parched pinnule's upper surface displays sunken furrows coinciding with veins. The rachis's upper surface, along the picture's right side, is even more conspicuously channeled than on its underside.

The fern's black petioles at their bases bear dispersed, large, sharp-pointed scales, a feature helping with identification.

In the 2019 volume of the Flora del Bajío treating the Maidenhair or Brake Family, the Pteridaceae, all the above features, especially the underturned, "interrupted" false indusia, led to the genus Aleuritopteris, of which only one species occurs here in upland central Mexico, and that's Aleuritopteris farinosa, with no English name. However, at this writing, Kew's Plants of the World Online database regards that name as a synonym of HEMIONITIS FARINOSA.

A fair number of other authorities still recognize the name Aleuritopteris farinosa, and recent genetic studies don't clarify matters. They do confirm that on the lipfern branch of the taxonomists' phylogentic Tree of Life, matters as they currently are, are a mess.

Hemionitis farinosa occurs throughout most of the world's tropical and subtropical highland regions, in thin, rocky soils, especially calcareous ones, on volcanic basaltic outcrops and in canyons.

I find no traditional Mexican uses of this fern, probably because it's an obscure species and too small to deal with.

It is, however, a fascinating species, which even in its parched, possibly dead, state, has its fascinating features.