Adapted from Jim Conrad's
Naturalist Newsletter of March 10, 2007
issued from Sierra Gorda Biosphere Reserve,
QUERÉTARO, MÉXICO

BUTTERWORTS

One plant I always look for when I head into the higher elevations in eastern Querétaro State is the butterwort. Actually, four Butterwort species are listed for the Reserve. A purple-flowered one that's probably PINGUICULA MACROPHYLLA is shown below:

Butterwort, PINGUICULA cf MACROPHYLLA

In that image, notice the long, slender spur extending behind the blossom and holding nectar for pollinators with long proboscises. It almost looks like a violet flower, but the plant's leaves are very unlike any violet.

Butterworts are insectivorous plants -- they "eat" insects and other tiny invertebrates, and even plant debris that gets stuck in the abundant, gland-tipped, sticky hairs mantling the butterworts' broad leaves. After catching something, butterwort leaves slowly curl around their catch to form a bowl below it or to increase contact. The complex "eating" process is described very well, and a fine diagram is provided showing a gland-topped hair and other leaf-surface digestive organs, at http://www.pinguicula.org/pages/culture/Overview.htm.

As that page explains, one feature enabling butterworts to soak up nutrients from disintegrating prey is that their pretty leaves are profusely perforated with tiny holes called cuticular gaps. These holes allow digestive secretions inside the leaf to exude onto the leaf's surface where digestion takes place. It's very rare in the world of flowering plants for a plant's interior juices to come into direct contact with the outside world.

You can imagine that having leaves filled with holes means that the plants can very easily dry out. That's the reason you don't find Butterworts anyplace but where the air stays humid most of the time -- as in shady sites in the Eastern Sierra Madre highlands, where rising air cools and moisture in the air often condenses. Pinguiculas here typically occur in or near mountaintop cloud forests.

Notice that the web address given above is at a website dedicated to nothing but Butterworts. You might enjoy browsing it from its front page at http://www.pinguicula.org/pages/pages_principales/content.html.