When I first thought about identifying this tree, I zoomed in on those leaves. The color of their undersides reminded me of many of the Miconia leaves around here. At least one species in Panama is called dos caras – named for the “two faces” of the leaves.

But a quick look shows that the sangrillo (left image below) lacks the longitudinal veins of the Miconia (right image below).

    

Since those longitudinal veins are characteristic of the entire family to which Miconia belongs – the Melastomataceae – and the sangrillo doesn’t have them, then I thought I’d better start the identification from scratch.

One of the most valuable parts of the book by Alwyn Gentry (A Field Guide to the Families and Genera of Woody Plants of Northwest South America …) is that he starts his keys with leaf arrangement, something quite easy to determine. In the case of sangrillo you can see the leaf arrangement in the image on the left, above – the leaves are opposite and they are also simple.

When I looked at Gentry’s book, I saw that if I could check just one more characteristic – the presence of latex – then I could really narrow down the families under consideration. So I tore off a leaf, looked at the leaf stalk, and knew immediately where the tree got its common name. There was a small amount of reddish-orange latex oozing from the stalk. That “little red” could have two meanings: there was not much of it, and it was more orange than red, so it was only “a little red.” I could wipe it onto my finger and see its color but I was completely unable to get a reasonable picture of it with my point-and-shoot camera. I had what I needed, though. I went back to Gentry’s key and found that trees in our area having these three characteristics:

• simple leaves
• opposite leaves
• presence of latex

fall into one of two families: 1) the dogbane or Apocynaceae family and 2) the clusia or Clusiaceae family.

Sangrillo belongs to the Clusiaceae family

I knew immediately to which family the sangrillo belonged – but it surprised me. It was not the Apocynaceae family, which tends to have large, beautiful flowers such as Plumeria, and their reproductive parts – the male stamens and the female pistils – are usually hidden by their petals. So it had to be that sangrillo belongs to the Clusiaceae family.

Why the surprise? Because we have many trees of the Clusia genus here, and their leaves are so smooth and leathery that I tended to generalize that feature onto the entire family. To do so is wrong, of course. The Clusiaceae family consists of about 37 genera and more than 1600 species. It includes, besides Clusia, St. John’s wort (the entire genus of Hypericum) and the delicious mangosteen (Garcinia mangostana) (wikipedia).

Once I knew the family, I bypassed keys and went straight for pictures. The book Trees and Shrubs of Panama, by Carrasquilla, is arranged by family, so I opened that book to the Clusiaceae and immediately found pictures of a Vismia latisepala that looked good, but I couldn’t see the details well enough to peg it.

So I turned to the Tree Atlas of Panama where I found three other Vismia species listed. What images that were there were good, but without supporting text, I could not be confident of my identification based on them.

At last, I found a key for the Vismia of Panama. It was in the Annals of the Missouri Botanical Garden (Vol 65, 1978) and it was written at a time when Vismia was considered to belong to a different family, the Hypericaceae.* Even the species name I came up with is no longer used, but the plant is still the same plant, and by tracking down synonyms, I was able to give a name to the sangrillo.

The features to look for, then, are:

Leaf blade usually < 20 cm long; base wedge-shaped or rounded

The length of the sangrillo leaves that I measured ranged from 11 to 17 cm, none even approached 20 cm. This feature immediately distinguishes the sangrillo from one other species of Vismia that is in Panama – Vismia macrophylla, which has leaf blades generally much longer than 20 cm.

Leaf underside lightly covered with short, soft, matted wooly hairs.

I simply could not photograph this feature, but from the description you can guess what short, soft, matted wooly hairs should feel like – and it does.

Outer sepals oblong to elliptic or lanceolate

Here is the sangrillo flower. I’ve never seen those globular buds open much further than this. The sepals are the outer covering for this flower and they have separated enough to show the petals and a little tuft, which I’ll come to shortly. These sepals are lance-shaped rather than oval-shaped, thus separating  sangrillo in the key from the species Vismia japurensis (and also from Vismia latisepala, the species I saw pictured in Carrasquilla’s book).

That tuft?

That tuft is part of the shaggy-haired lining of the inner surface of the petals. In the following image of the flower from Discover Life, the flower has been opened to reveal the shaggy lining of the petals and also the reproductive parts of the flower. There are five (female) pistils. The (male) stamens, in five tight bundles or fascicles, lie just inside the petals.

Sepals spread and may bend backward in fruit

This last feature helps separate sangrillo from the species Vismia guianensis, in which the sepals are pressed against the fruit.

The result: Vismia baccifera.

Vismia baccifera has been known by six other names. The name in the key I used was Vismia panamensis, which certainly suggests that it is a common tree here. The origin of the name Vismia has eluded me, but the (current) species name, baccifera, means “bearing berries,” which of course is true but which also would apply to any other member of the genus Vismia. I should also point out that the common name sangrillo, even though I’ve been using it as if it referred only to the one species, is in practice applied to most if not all the Panamanian species of Vismia.

Vismia baccifera is distributed throughout Central and Northern South America.

In Costa Rica, Vismia baccifera prefers open areas and occasionally proliferates rapidly, accelerating the natural recovery of a scrubland or secondary forest. The seeds are dispersed mainly by bats (Zamora et al.).

Once I read about the involvement of bats in the ecology of the tree, I went back and looked at it to see how easy it would be for bats to find these little fruits. Remember the position of the flowers in the bat-pollinated balsa tree? Well, here in Vismia baccifera, at least some of the fruits are sticking right up there at the very tops of the trees where bats can find them. A click to enlarge the image will make this clear.

Since the fruits are all over the tree, though, and not just at the tops of the crowns, it is likely that birds or other animals partake of the fruits as well. Although I have not found literature on birds eating the fruits of Vismia baccifera, birds are often seen in association with the trees. The top five birds noted are (ZipCode Zoo):

• a kingbird (Tyrannus melancholicus)
• Blue-gray Tanager (Thraupis episcopus)
• Turkey Vulture (Cathartes aura)
• Black Vulture (Coragyps atratus)
• Clay-colored Thrush (robin) (Turdus grayi)

All are listed in A Guide to the Birds of Panama except for the particular species of kingbird, Tyrannus melancholicus. I would guess that the vultures use the sangrillo as a perch, not as a food source, but Blue-gray Tanagers and Clay-colored Thrush are definitely fruit eaters.

In summary, then, this particular sangrillo is Vismia baccifera because it has

• leaves shorter than 20 cm
• short, wooly, matted hairs on its leaf undersides
• lance-shaped sepals that bend backward in fruit

One of its distinctive features is the shaggy-haired lining of the inner surface of its petals.

It’s in the Clusiaceae family because it has

• simple, opposite leaves
• latex

That little red latex is what gives sangrillo its common name in Panama. Bats are important in dispersing its seeds but fruit-eating birds are seen with it as well.

All in all, a fine small tree for a neotropical savanna.

_______________

*At the time of the publication of the key, the family Hypericaceae had only two genera in Panama: Vismia and Hypericum. The Vismia was distinguished from the Hypericum by having a petiole whereas Hypericum does not. (There were other differences, too, but this would have been the easy-to-spot difference I would have chosen.)

Once you’ve lived among these trees, though, you’re able to see their beautiful flowers and exotic fruits. I began to want to know which species of Clusia we had. There are 300 species of Clusia in the new world tropica (Maas), but only five species listed in the Tree Atlas of Panama, which made me think I might be able to discover which species we had. However, despite the excellent illustrations in the Tree Atlas, I was not confident of any identification.

So I turned to Robin Foster of the Field Museum of Chicago, who in turn told me about Barry Hammel. Hammel, of the Missouri Botanical Garden, is in Costa Rica at this moment as I write and he is working on the Flora of Costa Rica Manual. He very promptly and kindly answered my email query and suggested that this Clusia might be C. pratensis, which is, he said, “…mostly known from the dry savannas of Panama.” He said that some of the characters that help one recognize this species are:

1. the epidermis of the twigs peels off in fine strips
2. the flowers do not produce stamens (male reproductive structures)
3. it is mostly free-standing, as opposed to hemi-epiphytic (we’ll get into this shortly)

Let’s look at these features one at a time. When we do, I think we’ll see that Hammel is right.

The epidermis of the twigs peels off in fine strips

As soon as Hammel mentioned this characteristic, I went back outside and looked closely at a twig. Here it is. Notice the fine red wrinkly material on the surface of the twig.

When I rubbed my finger gently over the twig, the material came right off.

Check number 1 for C. pratensis.

Flowers do not produce stamens

To prove that the flowers of this tree do not produce stamens, I suppose I should have several dozens if not hundreds of photos of flowers without stamens. I don’t, but I can say that the flower in the next photo looks just like all the other flowers I’ve ever seen on this tree. In fact, one of the things that intrigued me early on about the flowers was the structure in the middle.

It turns out this central green mass is simply the female reproductive structure – the brownish (and very sticky!) ring is below the ovary and in some species this ring bears sacs containing pollen. There are, however, no pollen sacs or any other male reproductive structures in this species.

I had not known that a species could produce fruits without there ever being pollen involved. The term Hammel used was apomictic to describe the species – from apomixis, “[d]efined broadly as any form of asexual reproduction and narrowly, and more commonly, as seed production without fertilization.” [Harris] Wow.

So, check number 2 – this plant has no stamens – for C. pratensis.

Mostly free-standing

Clusia may be free-standing or they may be hemi-epiphytes. An epiphyte is a plant that “…grows upon another plant but does not draw food or water from it.” (Harris). Hemi- means “half,” so a hemi-epiphytic plant is “half-epiphyte.” Within the same species of Clusia there can be free-standing trees and trees that “half-grow” upon another. Clusia may not extract food nor water from the tree it half-grows upon, but it can certainly strangle such a tree, as I wrote about earlier.

It manages this hemi-epiphytic behavior by putting out “stilt roots” that, when they encounter another tree, begin to grow around it, until the trunk of the other tree is completely girdled. The red arrow points to the origin of this stilt root.

Most of the Clusia in our area, however, are free-standing, as is this young one.

So, check number 3, mostly free-standing, for Clusia pratensis.

So what does this word pratensis mean? According to Dave’s botanary it means “referring to a meadow.” Well, I guess meadows and savannas can be similar, so the name fits well enough. 

This may not be the end of the Clusia story, though. Hammel mentioned in his email message that it is possible that two other species of Clusia may very well be present in our area, so now, Sherlock cap on head, it is time to go looking for more.

But it has what we humans might call a nasty habit: it can strangle other trees, just like the famous strangler figs, of which the banyan is an example.

This one, found on our neighbor’s property as we were walking with them today, has strangled both a tree and a rock, though the rock probably didn’t care.

I’ Another feature of the tree I like is its bark.

But when our gardener saw a Clusia growing adjacent to one of our nance fruit trees, he cut it down.

Now I know why.

As usual, what strikes me as one of the most characteristic features of a plant is not what strikes botanists as important. In this case, it is what I consider the succulent nature of the leaves.

I looked at these leaves and the jointed branches and thought “jade plant.” Of course I knew it was not really a jade plant, but I thought there might be some kinship. Not much, it turns out. The jade plant is a member of the Crassulaceae family. That family is so named because of its thick leaves (Latin crassus means thick, fleshy).

Botanists describe the leaves of my plant as coriaceous (leathery) rather than as succulent. It is a member of the Clusiaceae family, named after 16th century Dutch botanist Carolus Clusius. This family may be considered the tropical equivalent of the St. John’s wort family of temperate climates. Interestingly, considering the recent enthusiasm for the mangosteen fruit, this plant is in the same family and subfamily, but not the same tribe, as the mangosteen.

After looking into it a little, I found that the “succulent” quality of a plant does not indicate a genetic relationship at all, since it is a feature that unrelated plants developed in separate ecosystems. At any rate, my plant probably is not succulent – in the sense of storing water – at all, just “leathery.”

The plant is most likely a species in the genus Clusia. That odd feature in the center of the flower, here in side view,

would tell a botanist whether this were a pistillate (female) flower or a staminate (male) flower. I’m too new to this study to say, but according to all my references, the Clusia male and female flowers are separate. I have only seen this one kind of flower, and I think it’s pistillate if indeed it’s equivalent to this image in the Manual de Plantas de Costa Rica

showing a small bee taking resin, which must account for that sticky feel I observed.

Most of the Clusia I see around here are shrubs or small trees, but it’s possible for them to become very large. There’s one near a seasonal stream that must be at least 20 meters tall.

The sap is a white latex which has been used as a caulking material. The tree is sometimes called the autograph tree because you can presumably etch your name in a leaf. Well, I was born in Missouri, so you have to show me…

Okay, well, at least I guess I’ve at least got the right genus name here!