Piptocoma discolor – A Tree in the Aster Family

In February of 2009, a young sapling shot up next to a rock in our back yard. One of the people working on a project for us told us to cut it down – that it was a weed. But Dario, our gardener at the time said, in Spanish, something along the lines of “Oh, no, don’t cut that one down. It’s a salvia silvestre.” He clearly was quite fond of it. Later that same month we had some strong winds and one of the trees that fell down was, to Dario’s dismay, a salvia silvestre.

So I was curious. It’s certainly not the Salvia in the mint family that we know from the Northern Hemisphere, but the leaves are a little reminiscent of sage to the touch. What plant is it, then?

After I saw the one that fell, I learned to recognize the mature tree. It has a trunk that reminds me of one of my favorite savanna trees – Miconia rubiginosa.

Having the images here side by side, I see that the trunks aren’t all that similar. The grooves of the “salvia” on the left are lighter in color and straighter than those of the Miconia on the right. Nevertheless, the bark in both cases is deeply grooved and the trunks of the mature trees are roughly similar diameters.

In an abandoned pasture, the “salvia” is likely one of the tallest of the trees there, but if it’s growing along side a quebrada (a spring, sometimes seasonal) it’s just one among other tall ones. When in bloom, it’s possible to see that the flowers are white, but that’s about all you can tell from the ground. The flowers are high up in the crown of the tree, impossible to reach.

I decided my only hope of seeing a flower close-up would be to wait until our sapling matured enough to bloom, with luck while it was still short enough for me to reach the flowers.

This year, 21 months after the first picture of the sapling was taken, it looked like this, and the top is out of sight – threaded into the nance tree (Byrsonima crassifolia) the sapling is beneath.

Quite a rapid growth, in my opinion, but not rapidly enough to produce flowers. Nice leaves, though, don’t you think?

Fortunately, another young tree nearby did have some flowers:

Enough to confirm my suspicion that this tree belongs to the aster family (Asteraceae).

I admit I groaned a little. The Asteraceae family is huge and its flowers are tiny. The flowers are so special they have their own terminology. The terms I’m about to use were gleaned from a wonderfully helpful page on the Flowers of Asteraceae at PlantzAfrica. What is shown in the image above is a cluster of synflorescences. One of them needs to be broken down a little so you can see what that means.

Here is a single synflorescence on the left. From it I plucked a head, or in Asteraceae terminology, a capitulum, which is next to the ruler. The capitulum is a small inflorescence or flower cluster. In this case, the cluster of flowers consists of two tiny flowers called florets. So a synflorescence is, you might say, an inflorescence of inflorescences. Perhaps a “compound inflorescence” would be a better term.

There’s a great deal more to the terminology, but this is enough to confirm that the plant belongs to the Asteraceae family. If I had to identify this plant based on a dissection of these tiny heads, I’d be in trouble. But I figured I could possibly get around the problem by holding in my head that this plant is a tree.

There aren’t that many trees in the Asteraceae family.

So I took a deep breath and pulled out my copy of Gentry’s field guide and plowed into Asteraceae. He listed 19 genera that contained trees, and I was preparing myself to read up on all 19 when I came across this description for the genus Pollalesta on page 349:

Medium-sized second growth and savanna trees with corymbose panicles. Leaves densely gray-pubescent below.

The accompanying illustration was promising. And yes, this is second growth in these pastures of the savanna.

Botanical side note: [definitions from the New Oxford American Dictionary]

• corymb = a flower cluster whose lower stalks are proportionally longer so that the flowers form a flat or slightly convex head. corymbose = adjective.
• panicle = a loose, branching cluster of flowers, as in oats.
• pubescent = covered with short soft hair; downy

This is what it’s often like for me – look up every third word or so in a description! Some of the terms are beginning to stick, but I despair of ever knowing them all. I do use a reference other than a standard dictionary, though. The book by Harris and Harris gives real botanical definitions and illustrates every term. It’s wonderful, but their definitions are a little too complex for my posts.

Next, I checked the Tree Atlas of Panama, and yes, trees of the genus Pollalesta are found here.

Next reference to check was Flora of Panama: Compositae [Compositae is the former name of the Asteraceae family]. Ah, success! Pollalesta is in Panama and it is represented by only one species: P. discolor. It’s enough to say that the description of the head (capitulum) fits and that there are two tiny flowers (florets) in the capitulum.

So, Pollalesta discolor it is. But wait. What’s this about Piptocoma discolor, the name in the title of this post?

Well, as happens fairly often in the plant identification world, a qualified botanist decided that Pollalesta was not really a separate genus but, on the traditional basis of the characteristics of the plants, should really be lumped together with the genus called Piptocoma. The only species in Costa Rica and Panama affected by this decision was Pollalesta discolor now called Piptocoma discolor. [Pruski] The complete official name now is Piptocoma discolor (Kunth) Pruski.

What is known about this tree, this Piptocoma discolor?
For one thing, it is found in abandoned pastures in Panama and Costa Rica, in dry to moist areas. It flowers in January and April and in November and December; it fruits in June, July, and December. [INBio]

It occurs from Costa Rica south into northwestern South America

In the province of Herrera here in Panama, it has the common name of negro [Spanish for "black"]. I suspect that name comes from the color of the inside of the bark, which is extremely dark. The Miconia rubiginosa tree that I mentioned earlier is known locally as canela negra, also, presumably because of the dark interior of the bark. In Herrera, at least, the Piptocoma is recognized as having some value in the pasture and so is not removed. It is said that its bark, pounded and mixed with water, gives a drink against snake bite. Don’t use that remedy on my say-so, though!

That’s about all I’ve been able to find about it. Not a popular tree, I suppose, except perhaps with our former gardener, Dario, and with me. I probably like it because Dario did, but you must admit the leaves are pretty, the bark is interesting, and it makes a nice tall tree in the pasture. I’ll probably never learn why Dario called it salvia silvestre, though.