Palicourea, another coffee relative

I nailed this one pretty much by accident yesterday.

I had it pegged as a member of the coffee or madder family (Rubiaceae) because it has

• simple, opposite leaves with no teeth or lobes
• stipules (sometimes described as leaflike appendages) between the bases of the leafstalks or petioles

Here are the stipules (click the image to enlarge it).

But I figured it would take awhile to get beyond the family identification. After all, there are about 600 genera in the family.

It happened, though, that yesterday I received a Google Alert on Rubiaceae that concerned a revision of the genus Palicourea Aubl. by Charlotte Taylor of the Missouri Botanical Garden. There was a tiny picture of a plant on the alert page, but I thought “That looks familiar.” And so…

The first place I turned was to my book, The Trees and Shrubs of Panama, by Luis G. Carrasquilla R., which is available only through the Smithsonian Tropical Research Institute. Plants are arranged by family in this book, and I knew the family, so I went straight to the Rubiaceae. There I found a Palicourea – it was P. guianensis Aubl. – but both the leaves and the flower clusters looked too broad to be “my” plant. The common name caught my eye, though – recadito, “little messenger” in Spanish. The message to me in this case was: P. guianensis Aubl. is not the plant in my woods. Unhappily, it was the only Palicourea described in the book.

I’d like to say the next place I turned was to the place where I got my answer, the Trees, Shrubs, and Palms of Panama database. But instead I spent a lot of time searching google and Flickr, more or less to reassure myself that Palicourea was the right genus.

In this browsing I learned that Palicourea is a genus of about 200 species of shrubs and small trees. One feature that characterizes the genus are its stipules, which “…usually have two lobes or awns on each side and are often united intrapetiolarly as well as interpetiolarly….”

Well, bingo! If you scroll back up and look at the stipules, you’ll see the two awns (which I thought of as forks). You’ll also see that the stipules are both between the petioles and the stem (intrapetiolar) and between the petioles (interpetiolar). There were more details about the flowers, but since I hadn’t been able to capture good flower images before the plant started producing fruit, I’m leaving that description alone for now.

I also learned that Palicourea is closely related to Psychotria (which includes the Hot Lips of a few posts back). That surprised me a little because of the coincidence that the two plants I photographed are within a few meters of each other on the floor of a planted pine forest. Not to make too much of that, though.

Next I sank a great deal of time trying to discover the origin of the word Palicourea. Is it based on a Latin description of the plant, or is it based on someone’s name? All my usual sources, and many more, failed me in this endeavor and I never did find out.

I finally went to the Tree Atlas of Panama where you find a checklist of the known trees in Panama as compiled by the Center for Tropical Forest Science. You can search by species name, by family, or by common name. Three species of Palicourea are known for Panama:

1. Palicourea guianensis
2. Palicourea triphylla
3. Palicourea tubuliflora

I had already eliminated P. guianensis because it is the one in my book, and studying the images at this site confirmed my decision. The leaves, flower clusters, and stipules were all wrong.

One look at the next two species names, and I suspected right away, which my plant might be. Look at the picture below and decide for yourself whether you’d vote for P. triphylla or P. tubuliflora.

You’re right! Almost any introduction to the Latin roots of our words will reveal that “tri-” means three and “phylla” has something to do with leaves. These three leaves form a small whorl around the plant stem, and this arrangement gives Palicourea triphylla its name. The photographs at the Panama atlas site confirm that we’re really looking at P. triphylla.

Now, if someone will just let me know where the word Palicourea originates, I’d be a happy camper.