JIM CONRAD'S
NATURALIST NEWSLETTER
Issued from Hacienda Chichen Resort
adjoining Chichén Itzá Ruins in
YUCATÁN, MÉXICO

November 21, 2010

ROADRUNNER RUNNING
Roadrunners are fairly common here, but I never thought I'd get a picture of one, since nearly always you see them only as they dart across the road. By the time you realize you're seeing a roadrunner, it's gone.

Last Sunday as I biked south of Pisté one streaked across the road before me but, as usual, by the time I'd stopped and gotten the camera out, he'd long since vanished into roadside grass. Though I readied the camera and waited for him to reappear, I kept thinking that it wasn't worth it. For, this was a game they'd been playing with me for years, as if really they were consciously teasing me with their sudden appearances followed by their inevitable disappearances.

I was about to put the camera away when a car began approaching from the other side. "If they really do enjoy crossing roads right in front of oncoming travelers, maybe this one will cross before this car," I thought to myself. As the car came into view I readied the camera, then when the car was the same distance from him as I'd been, he zipped across the road, I snapped, and got the movement-blurred image at http://www.backyardnature.net/n/10/101121rr.jpg.

This is the Lesser Roadrunner, GEOCOCCYX VELOX, different from the Greater Roadrunner, Geococcyx californianus, of the southwestern US, who not only is larger but also has a more heavily striped throat and chest. The Lesser occurs only along the Mexican Pacific coast south to Nicaragua, plus there's a disjunct "island" population restricted to northwestern Yucatan.

So, do roadrunners really like to cross roads in front of other road users? I can't imagine how it would benefit the bird, except maybe to keep its reflexes sharp, or to appeal to some sense of fun it may have.

*****

HUMMINGBIRD PUZZLE
The roadrunner was easy to identify, but it was hard to figure out who was the rufous-bottomed, madly zipping hummingbird who's been visiting the Wild Scarlet Sages next to the garden for the last week or so. You can see what that bird looked like at http://www.backyardnature.net/n/10/101121bb.jpg.

This is an immature bird, as attested by the fact that none of the adults illustrated in field guides match it, plus the green on the head is speckled, which often is the case with immatures acquiring their adult plumage. Still, three important field marks give the identity away:

Of the six or seven hummingbird species expected in this part of the Yucatan, two species have those features -- the Rufous-tailed and the Buff-bellied Hummingbirds. Actually, we're a bit north of the Rufous-tailed's distribution area, but with forest destruction and global warming stirring things up I wouldn't be surprised to find the species here.

The inset at the lower, right cues me that we have a Buff-bellied because that species' tail is forked just as the picture shows. The Rufous-tailed's isn't nearly as deeply incised.

So, Buff-bellied Hummingbird, AMAZILIA YUCATANENSIS. With yucatanensis in the binomial you might expect this species to be endemic to the Yucatán, but actually it's distributed from the southernmost tip of Texas along Mexico's Gulf Coast, then all through the Yucatán, northernmost Guatemala and northern Belize.

Its habitat is described as "arid to semihumid forest and edges, brushy scrub, clearings with flowers," which is exactly what we have here.

*****

LIMESTONE SENNA
Here and there nowadays you see a medium-size tree at its flowering peak, splendidly decked out with clusters of yellow, thumbnail-size blossoms. You can see such a tree on the southern outskirts of Pisté, next to the dandy bicycle Don Bruce lent me, at http://www.backyardnature.net/n/10/101121sn.jpg.

Up close it's clear that it's one of many species of the genus Senna, which are members of the Bean Family. The tree shows typical features of the genus -- yellow flowers and pinnately compound leaves, as shown at http://www.backyardnature.net/n/10/101121so.jpg.

Often we've looked at the "papilionaceous" blossoms of Bean Family species -- meaning that the flowers had a broad top petal, two side petals, and the two bottom petals were united along their sides into boat-shaped "keels," plus the stamens' filaments were fused at their bases, more or less surrounding the ovary. Senna flowers are different, looking like intermediate stages between classical papilionaceous blossoms and "normal" flowers, as shown in the flower close-up at http://www.backyardnature.net/n/10/101121sp.jpg.

The petals are unequal and the flower is asymmetric, but not to the extent of true papilionaceous flowers. The yellow, frankfurter-shaped items are the stamens' pollen producing anthers, but notice that above them lie three or so smaller stamens with much reduced anthers. Those are sterile stamens, which is very typical for Sennas. The long, slender, upward-arching ovary, which will become a long, slender legume, also is typical.

Based on fuzzy pictures of the species on the Internet, and its appearance in lists of plants known to occur here, I'm calling this SENNA RACEMOSA. The USDA names the species Limestone Senna, which concurs with the fact that the Yucatán is basically a big slab of limestone. The species is distributed in the Yucatan, Cuba and here and there in Central America.

The tree is used medicinally in the Yucatán against diarrhea and eye infections. I read that lab tests confirm that compounds from the leaves are antibacterial.

*****

NEEA
If you drive or ride a bus all through lowland tropical Mexico, Central America and even South America, watching vegetation along the roads, you'll be surprised how often the same species appear again and again. They're weeds adapted to very disturbed and unstable environments, and of course such habitats are too common everywhere, so the weeds that inhabit them also are widely distributed. And those weeds have taken the places of much rarer species that are more narrowly adapted to the more natural conditions that used to be there.

Happily, sometimes if such abused areas are let alone awhile, the former species return, if they haven't been completely extirpated from the area. The farther I bike from Pisté, and the deeper I hike into the forest away from the Hacienda, the more likely I am to encounter species I've never seen before, species more adapted to the mature forest that used to be here. A look at one such mature-forest species is shown at http://www.backyardnature.net/n/10/101121ne.jpg.

That ten-ft-tall (3m) bush is a member of the genus Neea, probably NEEA TENUIS, a member of the Four-O'Clock or Bougainvillea Family, the Nyctaginaceae. If you Google looking for pictures of it you won't have much luck, since not much is known about it.

Field marks cueing us that it's a Neea include its opposite, leathery leaves, the long-pedicled fruits, and the tips of the fruits, which display thickened, dark rings beneath their tiny points. Features indicating that this is the species tenuis include the fact that the panicle is longer than the leaves and dangles on a long, slender stem, or peduncle.

Neea tenuis is distributed from Mexico's central Gulf Coast through the Yucatán, probably to Costa Rica.

This is the kind of species you like to run into, not only because it's something new and pretty, but also because it's an indicator of an ecosystem gradually healing itself, which our forest is doing, having once been ranchland.

*****

HELIOCARPUS'S CURIOUS FLOWERS
Another tree not likely found in weedy areas is shown at http://www.backyardnature.net/n/10/101121he.jpg.

That's HELIOCARPUS DONNELL-SMITHII, traditionally placed in the Basswood Family, the Tiliaceae, but with genetic sequencing now assigned to the big Hibiscus Family. You can see one of its tiny flowers at http://www.backyardnature.net/n/10/101121hf.jpg.

Often we've pointed out here that a feature distinguishing the Hibiscus Family, the Malvaceae, is that stamens in flowers of the family have their filaments joined into cylinders surrounding the ovarys' slender styles. But you can see here that the filaments don't do that, so, what's the deal?

The deal is that as the Hibiscus Family traditionally was conceived, those cylinder-forming filaments did indeed constitute a fine field mark for the family. The Hibiscus Family was thought of as a good example of a well defined family. However, now that genetic sequencing reveals the true relationships of things, it's clear that some genera within the family don't have "staminal columns." And Heliocarpus is one of them. More and more it's becoming clear that "plant families" are artificial, not-very-exact pigeon-holes existing only in human minds, and not something really existing in Nature.

The tree's leaves bear conspicuous glands, as seen at http://www.backyardnature.net/n/10/101121hg.jpg.

That's the underside of Heliocarpus's hairy leaf, where it attaches to the petiole. The glands are the brownish, shiny things along the blade margins. They're appear only near the petiolse. The typical function of such glands is to attract ants, which discourage herbivores from feeding on the leaves.

*****

BLUE JACQUEMONTIAS GALORE
Cruising the Yucatán's weedy backroads at this time of year morning-glories simply bedazzle the eye. There are many kinds of them, with different flower colors and sizes and leaf shapes, and great numbers of the various kinds. For the most part they're weeds, but because of the color they lend the landscape and the bounty of nectar they provide pollinators, you're glad to see them, wishing them well.

One of the most abundant species nowadays forming thick blankets of mutually entangling, blue-flowered vines mantling bushes and low trees is shown at http://www.backyardnature.net/n/10/101121jq.jpg.

That's a tiny part of a mass covering an area larger than most gringo lawns, and it's hard to see how the shrubs and trees below them get enough light to stay alive. It was impressive.

This member of the Morning-Glory Family, the Convolvulaceae, is JACQUEMONTIA TAMNIFOLIA, so widely distributed in the American and African tropics that it's hard to say where it's native to. It's even fairly common in places throughout the US Southeast, and seems poised to move north with global warming. It was first noted in Missouri, for instance, only in 1979, but now is more commonly met with.

Most vines known as morning-glories are members of the large genus Ipomoea so, if you're a morning-glory purist, Jacquemontias aren't really morning-glories. Often in the US they're just called Jacquemontias, but Mexico is home to about 17 species of that genus so, since this is the common, blue one, I call it the Blue Jacquemontia.

How do you distinguish a real morning-glory -- a member of the genus Ipomoea -- from a Jacquemontia? One way is that the stigmas of Ipomoeas are more or less spherical, while stigmas of Jacquemontias are two-lobed, with each lobe being somewhat slender, giving the style/stigma ensemble above the ovary a T shape. Can you make out the two-lobed stigma in the Jacquemontia throat, residing among five stamens, at http://www.backyardnature.net/n/10/101121js.jpg?

Jacquemontia tamnifolia differs from other Jacquemontias in the way its flowers are bunched into such close heads, and there are slender bracts, or modified leaves, subtending each flower, as shown at http://www.backyardnature.net/n/10/101121jr.jpg.

Back in Yokdzonot a few miles west of here, in 2008 we ran into another Jacquemontia, Jacquemontia nodiflora. You might enjoy comparing that white-flowered species, paying special attention to its similar T-shaped style and stigma, with the current blue-flowered one, at http://www.backyardnature.net/yucatan/jacquemo.htm.

*****

A SHY LITTLE VINE
Occasionally over the years I've mentioned having once worked as a botanical illustrator at the University of Bayreuth, Bavaria, Germany. For scientific publications I drew the tiny flowers of a certain kind of "climbing milkweed." Now whenever I run into plants of that group it evokes good memories of a past life and I wonder which species I have. I ship pictures of my finds to my friend Ulli still back at the Uni, who continues doing research on the group, and he tells me what I've found.

So, last week a species not yet featured here appeared climbing over a stone wall in Pisté. You can see it at http://www.backyardnature.net/n/10/101121fu.jpg.

A flower, looking very much like the blossom of a common milkweed, is shown at http://www.backyardnature.net/n/10/101121fv.jpg.

Ulli says that this is FUNASTRUM BILOBUM. Those dark items between the white, oval things (corona lobes) are "pollinarium glands," each bearing two leglike "pollinia" descending behind the corona lobes, so that gland and pollinia form an upside-down V. When an insect's leg slips between the corona lobes, it catches in the narrow angle formed where the V's arms join, and the whole V structure is torn from the flower and carried to another flower on the insect's leg. That's what the flower wants, since the pollinia consist of waxy, packed-together globs of pollen. When pollinia are left on the next flower's "cap," pollination will be accomplished.

Back in Yokdzonot we met another Funastrum species, Funastrum lindenianum. You might enjoy comparing our current species with that other one at http://www.backyardnature.net/yucatan/funastru.jpg.

*****

WILFRIDO'S GARDEN CANCHÉ
Luis the gardener quit, so now we have a new gardener, Wilfrido. You can meet him next to his new canché at http://www.backyardnature.net/n/10/101121wf.jpg.

Like Luis, Wilfrido tends his own family milpa, or traditional cornfield, and he knows everything the typical Maya farmer knows about how to grow things, which is a lot. As soon as Wilfrido arrived and got most Pica-Pica vines cleared from the main garden area he set to work building his canché.

The beds behind Wilfrido, in Maya called eras, grow healthy crops of radishes, leaf lettuce, cilantro, garlic and, to the right of the garlic, lemongrass. Both the eras and the canché accomplish the goal of gathering soil in one place so that it's thick enough to be worked and to support plants. In the Yucatán this is often necessary because in many places the soil is exceedingly thin atop the limestone bedrock and so poor in organic matter that it dries out fast. The thinness isn't entirely the result of erosion caused by frequent deforestation. Friar Diego de Landa in his manuscript of 1566 Relación de las cosas de Yucatán writes:

Yucatán is a land of less soil than any I know, being all live flat stones with very little earth, so that there are few places where one can dig down a {unit of measure} without meeting great banks of large rocks.

The canché has the advantage over the beds on the ground in that it's harder for animals to get at the plants. You've heard about our animal depredations. The newest one is that someone, probably a Coati, dug up a cantaloupe-size jícama tuber, or yam-bean, and ate the whole thing, killing the sizable vine that had sprouted from it.

Wilfrido's canché is composed of an elevated bed of poles atop which banana leaves are placed thickly enough to hold the soil deposited atop it. It's not absolutely animal-proof, but it's a little more so than a bed on the ground.

*****

WHY BOTHER WITH PRESERVING SPECIES?
Finding the seldom documented Neea tenuis and Heliocarpus glanduliferous this week got me thinking about the value of lesser-known and unknown species. With the enormous variety of life that exists -- more kinds of yellow butterflies, green algae and hawthorn trees than one could ever comfortably wrap his or her head around -- if a species we've never heard of goes extinct, what's the big deal?

One argument always trotted out to support the preservation of minor species is that one never knows what unstudied species may turn out to provide the cure for cancer or some other dreaded disease. That's true, but probably most people reason that since we already know close to 2,000,000 species, probably we'd have the cure by now if it were really there, or else we'll soon stumble upon the compound in our pharmaceutical labs.

Another argument for preserving species is that the more species-rich an ecosystem is, including the planetary human one, the more stable and sustainable it is. That's true, but so few people really grasp that they are part of an ecosystem, or why stable ecosystems are safer, that that argument doesn't carry much weight, either.

I believe that most people will never become concerned about the preservation of the Earth's millions of lesser-known species until they mature spiritually. I'm not talking about religiosity, which is the acceptance of dogma someone else teaches you. Spirituality is that set of insights and feelings blossoming spontaneously when one beholds and reflects on the incomprehensible gorgeousness and complexity of the Universe, and wonders how we humans fit into the scheme of things, and what the implications are for how we ought to behave.

If you accept "Nature as Bible," it's pretty clear how important diversity has been to "the Creator." Remember that as soon as Earth cooled after its formation, life arose. And as soon as life arose, it began very vigorously evolving new species. Always, always, always new species arose, each species ever more subtly adapted to ever more nuanced environments, until today we have all these millions of species, most of them not yet known to science, and evolution continues as lustily as ever.

Well, if one is to have any guiding principle in his or her life, what is more appropriate for that person than to harmonize behavior with the whole general flow of the Universe -- with what the Creator WANTS? And the history of Life on Earth indicates that what the Creator wants here is ever more diversity, which is exactly what protecting lesser-known species is all about.

*****

Best wishes to all Newsletter readers,

Jim

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