Excerpts from Jim Conrad's
Naturalist Newsletter

from the June 25, 2017 Newsletter issued from Rancho Regensis north of Valladolid, Yucatán, MÉXICO

Last weekend on my banana-buying biking trip to Temozón I noticed a large bush or small tree with hat-size leaves flowering at the forest's edge, shown below:

Guettarda cf. coombsii, leaves and flowers

The big leaves with their numerous regularly spaced secondary veins connected with one another by very many short, tertiary veins, were more eye-catching than the flowers. The flowers whiteness did however show up nicely against the forest's deep green background. Below, you can see that the flowers' corollas displayed long, slender tubes:

Guettarda cf. coombsii, flowers from side

That picture shows the flowers' calyxes arising from atop roundish ovaries, which means that the flowers have inferior ovaries, and that's an important field mark. Below, you can see a flower from the front, displaying six corolla lobes, and with anther heads barely reaching the tube's opening

Guettarda cf. coombsii, flower from front

The inferior ovaries suggested the big Coffee or Madder Family, the Rubiaceae, so I checked to see if the leaves were opposite, and with stipules connecting the tops of the petioles. Below, you can see that the leaves were indeed opposite, and that the tops of their petiole bases were connected by stupendous stipules:

Guettarda cf. coombsii, stipules

So, it was a "Rube," and to my great pleasure it was a genus and species not well documented at all. My guess that we have GUETTARDA COOMBSII is mostly based on W.J. Hayden's pictures of that species' stipules and leaves at http://chalk.richmond.edu/flora-kaxil-kiuic/g/guettarda_coombsii.html

Hayden publishes his Flora of Kaxil-kiuic online. That location is in the eastern Yucatan, and Hayden's work has helped me with many identifications, like this one. However, so far he has no photos of flowers or fruits. Moreover, CICY, the Centro de Investicación Científica de Yucatán, in Mérida -- which provides information about the Yucatan's plants -- only mentions that members of the genus Guettarda are present in the Yucatan, but provides no information or images at all. Elsewhere on the Internet I couldn't find any flower pictures.

So, at this time, on the Internet, our roadside plant is very poorly documented, and here we may be providing pictures and information very hard to come by. That makes me feel good. Even if our plant is something other than Guettarda coombsii, at least by using that name here we're making the information findable to those searching for information about Guettarda and its species.