Excerpts from Jim Conrad's
Naturalist Newsletter

from the January 18, 2019 Newsletter issued from Rancho Regensis north of Valladolid, Yucatán, MÉXICO;
elevation ~40m (~130 ft), N~20.876°, W~88.170°
EK BALAM, THE PLANT

Thirty-four species of the genus Croton, in the Spurge/Euphorbia Family, are listed for the Yucatan Peninsula, and probably at least a dozen might occur in our area, maybe many more. But their taxonomy is a mess and they're hard to differentiate. So far I've only been fairly certain about one of the woody species, which I call the Tree Croton, whose page is at www.backyardnature.net/mexnat/croton2.htm

Now I'm maybe 80% sure of a very common Croton species that often turns up here along fencerows and livestock trails through the woods. A typical plant is shown below:

CROTON CHICHENENSIS

Crotons bear unisexual flowers, and our fence species bears racemes of either all male or all female flowers, so the plants are "dioecious." Below, you can see some young racemes of male flowers

CROTON CHICHENENSIS, male flowers

Already with that picture you can see what's true of most crotons: They're hairy. A male flower with numerous white stamens issuing from it wide open, hairy calyx is shown below:

CROTON CHICHENENSIS, male flower

A cluster of very different-looking young female flowers is shown below:

CROTON CHICHENENSIS, female flowers

The white items are styles emerging from small, fuzzy-white ovaries. Each style ends in a curled stigma. A cluster of more mature ovaries with their styles shriveling and turning brown is seen below:

CROTON CHICHENENSIS, mature female flowers

The white-woolly undersurface of a leaf is shown below:

CROTON CHICHENENSIS, hairy leaf underside

When croton leaves are plucked from a stem, usually a noticeable amount of clear or colored liquid issues from the break. In this species, the sap is orangish, as shown below:

CROTON CHICHENENSIS, orange sap & leaf base

That picture also shows that the plants' hairiness is largely composed of branched or "stellate" hairs. Also, leaf bases in this species project back toward the stem a little, so they're "shallowly cordate." The sinus between the two back-pointing lobes is narrow, and forked veins radiate from the juncture of the blade with the petiole.

All these details appear to lead to the species CROTON CHICHENENSIS, which has no common name in English. I read that a Maya name for it is Ek Balam. However, my friend Juan calls it Oregano Kaash, meaning "Wild Oregano." However, they don't use Croton chichenensis as a spice, as they do with another species they call by that name.

In certain parts of the rancho's forest where livestock graze, many trees are dying because their bark is being eaten off, and the herbaceous layer has been almost removed. However, wherever enough sunlight breaks through, large, single-species patches of Croton chichenensis are left untouched by the animals. I sampled a leaf and didn't find it particularly bitter, so livestock avoids this species for some reason other than its bitterness. If this overgrazing continues, in a few years we may have large areas of pure Croton chichenensis.

Despite its abundance and weediness here, Croton chichenensis is endemic only to the Yucatan Peninsula.