Excerpts from Jim Conrad's
Naturalist Newsletter

ACACIA (VACHELLIA) MAYANA

from the May 1, 2016 Newsletter with notes from a visit to Lacanja Chansayab in the Lacandon Reserve, Chiapas, MÉXICO
MAYAN BULL-HORN ACACIA
On April 13th on my walk up the little paved road leading into the Lacandon village of Lacanja Chansayab in Chiapas's Lacandon Reserve, right at the road's edge where a bridge crossed the Lacanja River on the town's north side, a four-meter-tall (13ft) bull-horn acacia turned up looking like no other acacia I'd ever seen. Its big thorns, ferny leaves and flower spikes are on display atop this page.

This is a kind of bull-horn acacia. In the Yucatan we have plenty of bull-horn acacias but the Yucatan's species produce thorns that are round in cross section, not broad-based and "winged,"like these. Below, you can take a closer look at a pair of this tree's amazing thorns.

ACACIA (VACHELLIA) MAYANA, thorns

With such winged spines I knew we had something interesting, so I photographed other details that might be important for identification purposes. For example, there were glands along the compound leaves' rachises, maybe for the production of an edible substance for the very aggressive biting ants living in the hollow thorns -- typical for the bull-horn acacias -- and those are shown below:

ACACIA (VACHELLIA) MAYANA, glands on leaf rachis

Later I sent the above pictures to Dr. Wolf-Achim Roland in Solingen, Germany, who produces a fine website on the world's Acacias. We're friends despite his being one of those specialists encouraging the breakup of the old, famous genus Acacia into small, hard-to-remember genera. He quickly replied that our Chiapas tree is Vachellia mayana, which we who hesitate to abandon the noble genus Acacia still call ACACIA MAYANA. The species has no English name but I don't think anyone will object if we call it the Maya Bull-horn Acacia.

Acacia mayana is endemic just to that part of Mexico stretching from southern Veracruz State on the Gulf of Mexico, through Oaxaca and Chiapas into part of lowland northern Guatemala, the Petén area. It's described as one of the rarer ant-acacias, one specializing in lowland wet forest and forest margins. Therefore, our pictures and notes are likely to make acacia enthusiasts very happy.

One final note worth mentioning is that I read that Acacia mayana produces a large supply of Beltian bodies, which are yellow, protein-rich packets attached to leaflets, serving as ant food. They're shown and described on another bull-horn acacia page at http://www.backyardnature.net/yucatan/acacia-t.htm

The literature says that on developing leaves of Acacia mayana nearly all leaflets contain Beltian bodies, and these bodies are usually about 2 mm long and up to 0.8 mm wide, which is much larger than what we've seen on our Yucatan acacias. Our Acacia mayana was flowering in the heart of Chiapas's dry season, the tree bore no developing leaves, and none of its old ones bore Beltian bodies.