The top graph is of wind direction, with North at both the top and the bottom and South in the center, to accommodate 360 degrees stretched out in a straight line. The bottom graph is rainfall rate in inches per hour. Note the scale – maximum is 5 inches per hour. Most home rain gauges capture up to 5 inches, assuming it will be read once per day.

Boquete is not here where we are, but the personal weather station that recorded these data is located 6 miles due north of us and uphill by 1740 feet (530 m).

The river that flows through Boquete flooded, of course, and a resident of the area has posted photos of the damage at Picasa.

For us, on that day, the intense rains were of much shorter duration and occurred at the time of a secondary peak in the Boquete rain. Note that our scale goes to only 4.5 inches/hour.

This particular episode may have been related to a trough located near the Intertropical Convergenze Zone and possibly also by the activity of Tropical Storm Frank in the Pacific.

Whew.

In July we broke the monthly record for rainfall since Señor Espinosa started keeping track of rain in our area in 1992. The previous record – for September 1999 – was 55.3 inches. This July we exceeded that amount by exactly 4 inches; our total was 59.3 inches.

It rained 29 of the 31 days in July and on one of those days, it rained more than five inches.

Meanwhile, our average temperature has been 71 degrees F.

We have a few more tidbits at our weather archives page.

There are lots of sprawling, scrambling vines around, but this one I like because of its red inflorescence and also its trifoliate leaves. When I took a clipping or two home and and opened my trusted identification manual by Gentry in hand, it didn’t take long to come up with the family and genus name of this woody vine.

Leaves alternate and compound

The leaves are divided into three leaflets, which makes them compound leaves, and they are not opposite each other on the stem – they work their way up the stem on alternate sides.

This combination of alternate, compound leaves is most often found in the legume (Fabaceae) family, but legume leaves have smooth edges or margins. The margins of the leaves on this woody vine are toothed, or serrated.

The toothed edges place it in one of three possible families: the soapberry (Sapindaceae), the cucumber (Cucurbitaceae), or the grape (Vitaceae) family.

Crucial tendrils

To distinguish the families from each other, Gentry uses the configuration of the tendrils. Soapberry tendrils are bifurcated or forked. Cucumber tendrils are divided, spirally coiling, and make a right angle with the base of the leaf stalk. Grape tendrils arise on the stem opposite the leaf stalk – in the exact position another leaf would be if these leaves were opposite rather than alternate.

So which tendrils do we have here?

Member of the Vitaceae family

The tendril arises on the stem opposite the leaf stalk, which makes it a member of the grape, or Vitaceae, family.

Member of the Cissus genus

Once the plant had been placed in the grape family, it was straightforward to find the genus. In the discussion of Vitaceae, Gentry says:

Several Cissus species have 3-foliate leaves. The commonest of these have a characteristic 4-angled, subwinged branchlet . . . also usually distinctive in swollen nodes.

Here’s the 4-angled stem:

Nodes are where the leaves are attached to the stem. You can get a hint of the swollen node in the above picture. It’s a little more dramatic in this one:

Botanical Aside: Why I love Gentry

To me, those three easy-to-see characteristics listed by Gentry took me straight to the genus name of this plant. Had I not used this book and had somehow managed to place the plant in the Vitaceae family, I would have then turned to the classic paper on Vitaceae by Elias, in the Flora of Panama series.

There I would have learned that the grape family is represented by only two genera in Panama – Vitis and Cissus – and these two are distinguished, by their flower clusters, or inflorescences.

Vitis has paniculate flower clusters. Cissus has cymose flower clusters. Vitis is the genus name for grapes, including the cultivated grape, Vitis vinifera. Its inflorescence is on the left (photo from wikimedia commons) and the inflorescence for my Cissus vine is on the right. A panicle (adjective = paniculate) on the left and a cyme (adjective = cymose) on the right. Can you tell the difference just by looking?

I can’t. Inflorescence terminology is something that intimidates me greatly, and if the terms in the last paragraph had your head spinning, I sympathize. I find myself learning the terms on a need-to-know basis. I decided I needed to know the difference between paniculate and cymose in this case so I looked up the terms.

It got a little more complicated when I found that the grape panicles are racemose and that the Cissus cymes are compound. In the end, the important part about distinguishing these flower clusters is discovering the order in which the flowers mature.

• • In a cyme, the flower at the end of the stem matures first.
  • In the grape panicle, the flower at the base of the central stem of the flower cluster matures first. The fact that the panicle is racemose is what tells you this.

These are important differences, but for an amateur who wants to get to the name first and to study the botany and ecology with name in hand, it slows one down to use inflorescence as a distinguishing characteristic. If the leaf type and arrangement can do it, then I’m all for it.

So that’s why I love Gentry. I learned that the plant in my hand was a Cissus without having to first learn the difference between cyme and raceme. But, of course, now that I do know the difference, I can do something with it, and so here we go.

Proof of cyme, anyway: In a simple cyme, the flower at the end of the stem matures first. In a compound cyme the flower at the end of each axil in the flower cluster matures first. So here’s a look at an individual axil. Sure enough, the central, terminal flower has clearly matured before the other flowers on the axil; the fruit has already developed from the central flower (and it is in focus whereas the flowers elsewhere are not).

So this woody vine is in the genus Cissus, by all kinds of criteria.

Incidentally, a very nice sequence of racemose flower maturation (shown in grapes, not in Cissus) is in this post on Virginia Sweetspire. It may help to know that the word raceme comes from the Latin racemus, which means “bunch of grapes.”

End of Botanical Aside: Enough on cyme, cymose, panicle, and racemose, then.

Working out the species

When Elias worked out the key for Panamanian Cissus, he listed four species that were trifoliate. For now, let’s call them species A, B, C, and D.

To sort them out, first characteristic he looked at was whether the leaves were rhombic in shape or elliptical to oval, with the narrower end at the base. He made note that the plants with rhombic-shaped leaves tended to be fuzzy with hairs. The leaflets in this Cissus (seen in the image earlier) are more or less oval shaped and are smooth to the touch. The Cissus with rhombic-shaped leaves is species A.

Then the species with leaves that are roughly oval and smooth to the touch are separated on the basis of the length of the peduncle, or the main stalk of the flower cluster. If it’s between 7 and 12 cm long, its stems tend to be 4-sided and the fruits 4-6 mm in diameter. This is Cissus species B.

Here we see a stalk that 7.4 cm long and a nearly mature fruit that is 5 mm in diameter.

If the stalk is shorter and the fruits larger, then we have species C or D and they are further distinguished by other criteria..

So by the criteria of flower stalk size and fruit size, together with the 4-sided stem, this woody vine, species B, is Cissus erosa.

PS: The names of all four species of Cissus described by Elias in 1968 are:

• species A = C. rhombifolia
• species B = C. erosa
• species C = C. microcarpa
• species D = C. martiniana

We now know that there are more species of Cissus in Panama than these four, but that’s enough for now.

Cissus erosa

Cissus is the Latin name for ivy. (Certain cultivated species of Cissus are called “grape ivy.”) In the United States, plants of the genus Cissus are called “treebine,” and these plants are often compared to Virginia Creeper or five-leaved ivy. Same family, different genus.

The species name erosa means jagged, perhaps because of the rather rough leaf stalk. Here’s a zoom in on the stem image:

Cissus erosa is widely distributed in Central and South America, where it is known as caro de tres hojas or “dear three leaves.”

Why Scrambler?

The title of this post is “Cissus the Scrambler.” The thought of a vine or liana as “scrambling” over low-lying plants or, in the case of some of these plants, over a forestry road, came to me after reading a chapter about “Hangers On” in the book Tropical Nature. There’s a great discussion of the impact a climbing vine can have on the tree that it is climbing. It can, in fact, be devastating.

All leaves, whether on a vine, a shrub, a tree or any other plant, need sunlight. If plants are near the ground, then they must either find a sunny area or adapt to the lesser sunlight in the shade of a tree. Woody vines or lianas, not having trunks or sturdy stems like shrubs, travel to reach the sun. They may use tendrils or they may use their entire stems to wrap around a shrub or tree and therefore climb.

A tendril can coil around small things – the tendrils of this Cissus erosa even coiled around pine needles and grass stems on the forest floor. These tendrils could never coil around a tree trunk, so lianas like this one sprawl out in sunlit clearings, and may climb over small shrubs if their tendrils can wrap around the twigs. These are the scramblers, spreading out as fully as possible in forest clearings.

The lianas that climb trees must start out in the shade. They find their sun at the very top of the tree canopy, and the story of how they change as they climb by coiling their stem around the tree is a fascinating one, not to be discussed here (but read the book, it’s good!). There they start competing for space in the sun with the very trees they’ve climbed. No tendrils involved, but stems strong and sometimes thick enough to support large mammals.

Cissus, the scrambler, will never provide a swing for Tarzan. It finds the sun it needs close to the ground, in forest clearings, or crossing forestry roads.

Wrapping it up

Cissus erosa has

• alternate, compound (trifoliate) leaves
• tendrils opposite the leaf

which make it a member of the grape family, Vitaceae.

It has

• a 4-sided stem
• swollen nodes
• compound cymose inflorescence

which make it a member of the genus Cissus.

It has

• leaflets that are roughly oval and smooth to the touch
• a peduncle between 7 and 12 cm
• fruits 4-6 cm in diameter

which make it a member of the species erosa.

Its tendrils are fine enough to wrap around a pine needle or a grass stalk and are used to move the plant along across a clearing or to scramble over shrubs with thin twigs. Nowadays, when nearly everything in the forest is so very green, it’s nice to come upon a clearing and to see a cluster of red . . . a cyme (!) of Cissus.

——

Note: The “Botanical Aside” was inspired by the “Side Notes” used in Watching the World Wake Up, where they are an art form.

So far this year we’ve had 134 inches (11 feet) and we’re two weeks away from August.

Some days, the standard 5-inch rain gauge doesn’t hack it.

Just saying.

A note on the host blog: Agricultural Biodiversity may sound a bit dry to you, but if you follow the blog even for a short time, you’ll see that the issue is far larger than simply keeping agriculture from becoming an industry that produces only a few, almost mechanized, foods. Just skim down the list of categories – there are 46! – to get an idea of the topics covered. Plus, Jeremy’s style, as you’ll see in the BGR carnival, is lively and opinionated.

Back in May, I noted the early blooming of Miconia rubiginosa after the heavy rains in April.

Now, in July, I’ve seen two plants in bloom that I normally see bloom in August: a tree with large bunches of yellow flowers, Senna hayesiana, and a miniature relative of the Elephant Ear herb, Xanthosoma mexicanum. I’m also seeing flower buds on an unidentified Miconia that usually blooms in September. I’m sure more’s going on along this line than I’m seeing.

Maybe these large swings in time of blooming are relatively normal for the tropics. But I’m starting to think that it’s more than coincidence that different plants from three unrelated families (Senna = Fabaceae or bean family, Xanthosoma = Araceae or arum family, Miconia = Melastomataceae or “black mouth” family)  are blooming immediately after uncommonly large monthly rainfalls.

To refresh your memory,

A Witch’s broom is a disease or deformity in a woody plant, typically a tree, where the natural structure of the plant is changed. A dense mass of shoots grows from a single point, with the resulting structure resembling a broom or a bird’s nest.

First recorded instance in Sapindaceae
The Allophylus tree is in the family Sapindaceae, the soapberry family, and I went looking for other instances of witch’s broom in that family. But Dr. Pedro Acevedo, of the Smithsonian Institution and a specialist in Sapindaceae, wrote to me that this is “…the first time that I know of the occurrence of witches’ brooms in Sapindaceae.”

The agent that causes this witch’s broom is not known, either, unsurprisingly. An expert in fungus, Dr. Meike Piepenbring, wrote to me that she has seen several witches’ brooms on avocado and on native plants here in Panama, but not on Allophylus. She found the presence of, not fungi, but aphids. After studying the literature, she concluded that the most probable agent is for the witch’s brooms that she saw is mites, but she has not yet seen these mites herself.

Ted MacRae, in a comment on my earlier notes on this witch’s broom, had suggested that I might look for mites, and I did. I found one on the first “broom” I examined. I have since, very unscientifically, looked through more than a dozen or so brooms, chopping them up with pruning shears, and have found a few more mites, a couple of tiny beetles, a weird-looking white flat thing that I couldn’t begin to identify, several very small and various spiders, and no fungal spores, at least not any detectable with my 16X hand lens. I don’t have much hope of discovering the causal agent all on my own.

Not so innocent brooms
One little broom all by itself doesn’t look so bad, especially since it has taken the basic shape of the inflorescence and become carried away with it, so that it looks like it might give rise to a robust bloom of small flowers.

But once you know that witch’s broom is a disease and that it could harm the tree (for instance, witch’s broom is a grave threat to cocoa production), they’re not so attractive. Here’s a portion of a tree that is infested with these things.

Maybe even these green brooms don’t look so bad to you, but they look pretty nasty after they’ve “died” or whatever they do after they’ve accomplished their purpose. The brown or black ones may be a little harder to see, even after you click the image on the left. So I’ve circled them in the image on the right, which is also clickable.

No self-respecting inflorescence would end up looking like that!

It is my hope that a graduate student somewhere with an interest in Sapindaceae stumbles across this post and decides to write a thesis on witch’s broom in Allophyllus psilospermus! Wouldn’t that be great?

On the following graph, the blue line is the 17-year average for each month of the year, and the red line represents the rain we’ve had so far this year. Months that have more than 10 inches of rain occur during our rainy season, thus our rainy season extends from May through November, a period of seven months.

March had rainfall pretty close to average, but February and April were way off the average line. Because April was so far above average (it qualified as a rainy season month this year) and because May was so on-the-nose average, I decided to look at just how often do we have average rainfall in any given month.

What is average?

Here’s a graph representing each of 17 years of rainfall, superimposed on the average (thick black line).

On seeing this graph, one person remarked that “It looks like there’s not a single average year on that graph!”

So I wondered – how many months actually have average rainfall? I created a table showing the deviation from average for each month. (You may have to click on the table to see it more clearly.)

I highlighted the months that differed from the average by 1 inch or less and then totaled those months in the last row. A total of 28 months during that 17-year period had within an inch of average rainfall. This is 14% of the months represented. We can therefore expect that we will have non-average monthly rainfall 86% of the time.

Over that 17-year period, August never had near-average rainfall. September had the greatest deviations from the average – more than two feet of rain (24.4 inches) above average in 1999 and 20.4 inches of rain below average in 2009.

Does El Niño have anything to do with this?

It turns out that the 2009/2010 El Niño dissipated in May of this year. You may have noticed in the table above that from June through September of 2009, rainfall was below average, usually several inches below average. This is the typical pattern of El Niño in Panama – below average rainfall in the rainy season – leading to droughts – and (slightly) above average rainfall in the dry season. With the dissipation of El Niño in May, our rainfall returned to exactly average.

If El Niños result in less rainfall in Panama during the rainy season, then La Niñas result in more rainfall during the rainy season. Note that the September 2-ft excess rainfall was in 1999 and that rainy season months August through November of that year all had higher than average rainfall. That year, 1999, was a La Niña year.

Back in graduate school, when I first learned about El Niño and atmospheric circulation as a basis for understanding the surface currents of the oceans, we learned that El Niño occurs more or less every 30 years. This gives you an idea about how long ago I was in graduate school! It seems these days that we’re either in an El Niño or a La Niña practically all the time. In fact, NOAA’s Climate Prediction Center states that “Conditions are favorable for a transition to La Niña conditions during June – August 2010.”

Grateful as we may be for average rainfall this May, it looks like average conditions won’t last long, and we may be in for some heavy rain this year.

Update: Carla Black has posted a comment giving the rainfall data from Volcan, which is to the west of us and uphill by a great deal, but still on the Pacific slope side of Volcan Baru. You’ll see that their May rainfall, unlike ours, was far below average.

A lesson from this observation is that local conditions can seem to overwhelm global conditions at any particular time. For instance, last month Carla sent me 13-year’s worth of rainfall data from Aprils in Volcan. This exchange was prompted because here in Potrerillos we had an extraordinarily high rainfall this April. When I plotted all 13 Aprils from Volcan vs. the same 13 Aprils in Potrerillos, I found that there was no correlation between rainfall in the two places whatsoever. Yes, there’s a slope to the line, but the r-squared value, which shows whether there is any significance to that slope, is about 0.2, which says that there is a 20% chance that the data are related. Or an 80% chance that they are not related.

So, if it’s raining in Potrerillos, we cannot predict at all whether it will be raining in Volcan. For example, she wrote that it had been raining for six hours in Volcan – at the moment I received her comment it had only begun to rain here and has now done so for about one hour.

Good lesson!

And thanks, Greg, for including The Corotú and the Gomphothere in your selection!