December 18, 2011
HARVESTMAN IN THE WOODS
We have those long-legged arachnids with oval bodies called harvestmen or daddy-longlegs down here, too, such as the pink-bodied one seen sprawling on a leaf at http://www.backyardnature.net/n/11/111218ll.jpg.
Most Northerners think of harvestmen as living in dank basements and old buildings, but this one was in deep forest. Lots of species exist, in several genera, and they occupy many environments. Several species live in caves and are blind. The one in the picture let me get close enough to see the interesting features shown at http://www.backyardnature.net/n/11/111218lm.jpg.
Harvestmen are related to spiders but they're not considered to be spiders themselves. Spiders produce venom and silk, but harvestmen don't. Spiders typically have up to eight eyes, but harvestmen just have two, if they have any at all. In the picture the two objects looking like eyes are indeed simple eyes with single lenses. Technically they're called ocelli. In most harvestmen the ocelli are located on a bump known as the ocular tubercle, visible in the picture.
Below the eyes notice the slender, pale things bent beneath the body, looking like fangs. Wikipedia's harvestman expert assures us that while spiders have fangs, harvestmen don't. Our harvestman's fanglike items are called chelicerae, which are defined as "fanglike appendages near the mouth of an arachnid, often used for grasping and piercing." It sounds like you need to be an anatomist to appreciate the difference between a fang and a piercing chelicera.
Numerous species and genera of harvestmen are recognized and I'm not at all sure which one we have here. It's similar to North America's Hadrobunus grandis, so maybe it's closely related or in fact the same species.
KATYDID WARMING IN THE SUN
On some mornings this week it was chilly enough for your breath to form steam if you stepped outside after drinking something hot. However, most mornings also have been clear, so at sunrise the sun's rays soon began burning off dew and warming things up. That's when butterflies find leaves facing directly into the sun and for several minutes perch holding their wings perpendicular to the incoming rays, basking. Birds perch on high, leafless snags preening in the sunlight, or just sitting there looking about.
On a Chaya bush next to the hut, on two such mornings an angular-winged katydid cautiously leaned from her overnight shelter of two leaves almost touching another below, exposing herself to the sun, as shown at http://www.backyardnature.net/n/11/111218ky.jpg.
Since a katydid has been showing up in the same general area almost daily for the last two weeks, I'll bet that this is the same one we looked at last week when she was still in a nymphal stage with her wings not yet expanded. You can review last week's picture at http://www.backyardnature.net/yucatan/katy2.htm.
DO SPIDERS EAT HONEYBEES?
If you've ever wondered about that -- since it would seem that honeybees might defend themselves -- look at http://www.backyardnature.net/n/11/111218lx.jpg.
The spider looks like the Green Lynx spider, PEUCETIA VIRIDANS, the same species found in the US southern states from coast to coast, south through Mexico, the Caribbean, into Central America. In the picture the bee has strands of spider silk adhering. Either that silk belongs to another spider species or it's the Lynx's dragline, because Green Lynxes don't make webs, just trail silk draglines, even when jumping.
Green Lynxes are among the most commonly encountered and successfully hunting of spiders in our area, ranging over vegetation like wolves through the woods. They're important predators of both insects that damage plants and pollinators the plants need.
ACACIA-LIKE TREE WITH PATCHY, FLAKING BARK
In the Yucatán the farther northwest you go the more arid it becomes, the lower and more scrubby the vegetation is, and the more species of feathery-leafed trees belonging to the Bean Family you find. Newcomers are overwhelmed trying to sort out all the acacia-like trees. One of those trees is easy to distinguish, though, merely from its bark and leaves. Basically, it's the one with frilly, acacia-like leaves but a patchy, scaly, sycamore-like trunk. You can see a typically mottled, very actively flaking-off trunk at http://www.backyardnature.net/n/11/111218ac.jpg.
Often around the base of such trees the ground will be completely covered with dry, curled-up flakes shed from the trunk. Now look at its twice-compound leaf at http://www.backyardnature.net/n/11/111218ad.jpg.
The whole picture shows just one "bipinnate," or twice divided, leaf with half-inch-long leaflets (12mm). The blade atop the petiole is divided into six primary divisions, and each primary division is subdivided into ten or so leaflets arising opposite one another.
This interesting tree, common here, especially where limestone bedrock juts from the soil, is a member of the Bean Family like the acacia, as well as a member of the Mimosa Subfamily, also like the acacia, but it belongs to a genus I'd never heard of before arriving here. It's CHLOROLEUCON MANGANSE, and there's not much about it on the Internet. My impression is that it's endemic just to the Yucatán.
Especially at roadside woods edges nowadays here and there you see a white-flowered vine overtopping weedy vegetation and often climbing high into trees. Its dense masses of smallish, white flowers with attendant glossy-green leaves spectacularly blanket areas the size of houses. You can see some flowers and leaves at http://www.backyardnature.net/n/11/111218cd.jpg.
The leaves are trifoliate -- compound leaves divided into three oval leaflets. In the picture at the top, left, notice how three leaflets join at their stems, or "petiolules," atop a petiole connecting to the stem. A close-up of a flower can be seen at http://www.backyardnature.net/n/11/111218ce.jpg.
The fuzzy, downward-curving things are sepals. The white, matchstick-like items are pollen-producing stamens. In their center you can barely see a pistil's neck, or style. Several vestigial female pistils are hidden among the stamen bases. I refer to "vestigial" pistils because the vines have either functionally male or female flowers. The flower in the picture has robust stamens but insubstantial pistils, so it's functionally male. Something else curious about this blossom is that there's no sign of a corolla.
The lack of a corolla, the numerous stamens, the several vestigial pistils, and the trifoliate leaves, all combine to form good fieldmarks pointing to the fact that what we have here is a clematis vine. Most clematis flowers bear both male and female parts, but this species produces separate functionally male and functionally female plants; the plants are "dioecious."
In fact, this is CLEMATIS DIOICA, its name celebrating its dioeciousness. The species is fairly common throughout tropical America, including the Caribbean.
Clematises are generally known as leather flowers, virgin's-bowers, or just clematises. I can't find any good English name for this one, so I think of it simply as White Clematis. Like other clematises, after flowering this species forms conspicuous, fluffy fruiting heads which once, I read, were gathered for stuffing pillows and cushions.
The vine seems to have captured the imagination of Mexicans, who variously call it Barbas de Viejo (Old Man's Whiskers), Barbas de Chivo (Goat's Whiskers), Cabeza de Viejo (Old Man's Head), Pelo de Angel (Angel Hair), Nube (Cloud), Pestañas de Tecolote (Owl's Eyelashes), and other Spanish names. In Maya it's Meexmuxab. Throughout the Americas it must have hundreds of names!
One reason for its multitudinous names may be that traditionally the vine has been used medicinally in many ways, especially for skin and tooth problems. Also coughs, hemorrhoids, and kidney ailments. And certain livestock diseases. Well, the uses go on and on, though the online Atlas de las Plantas de la Medicina Tradicional Mexicana says that no scientific studies have substantiated its usefulness for anything.
A DARK EYED, VIOLACEOUS MORNING-GLORY
"Violaceous" is a nice word, meaning "of a violet hue." We have Violaceous Trogons here, for instance. Trying to make sense of all the morning-glory species here, lately I've progressed from lumping all the bluish-and purplish-flowered species together, to discriminating between those blossoms that are more sky-blue and others that are violaceous.
But even still we have quite a few violaceous-flowered species. Once I got that through my head, I began noticing that most flowers in that group had white throats, or "eyes," but a few had dark ones. Then I began noticing that the two most common dark-centered, violaceous blossoms had very different calyxes. At that point, I could start digging for names.
For example, along trails out in the woods often you see a species with blossoms raised high above its leaf level, its flowers stretching toward sunlight, as seen at http://www.backyardnature.net/n/11/111218i5.jpg.
You can see its dark center (and a basking skipper) at http://www.backyardnature.net/n/11/111218i6.jpg.
Its pale green, oval, broadly overlapping, thin-edged sepals, the outer ones shorter than the inner, are at http://www.backyardnature.net/n/11/111218i7.jpg.
All these features seem to narrow the species to this: IPOMEA TILIACEA, a species known to grow from southern Mexico and the Caribbean through Central America, and in Brazil.
We've already looked at the other violaceous species, at http://www.backyardnature.net/yucatan/ipomoea9.htm.
What's notable is that that other species, I. crinicalyx, is just about identical with I. tiliaceae, except for its calyx's long, green, fleshy "hairs."
So, why did Nature set two morning-glory species to flowering at the same time in pretty much the same habitat and locality, looking practically identical, except for great differences in the calyx? Even knowing how evolutionary history often explains such phenomena, I think of the answer in terms of Nature's pure gusto for engendering diversity.
What a pleasure being drawn into Nature's seeming anarchy, always knowing that eventually things will start making sense, with systematic patterns becoming apparent. But, then, just when you're starting to think that Nature is all geometry, you're reminded of such questions as the above, the old mysteriousness returns, and you know that pursuing your new question eventually will carry you to the next level of inquiry and understanding. Which will lead to the next, and the next...
LIMA BEAN FLOWERS
Last year at this time we looked at the robust, red-seeded Maya Lima Bean, all discussed and illustrated at http://www.backyardnature.net/yucatan/limabean.htm.
At that time it was too late to find a flower but this year I have one, and it's curious enough to be worth looking at and thinking about.
Lima Beans are PHASEOLUS LUNATUS. Besides Lima Beans, the genus Phaseolus includes Kidney, Mung, Adzuki, Sieva, Scarlet Runner and other important cultivars, so it's a big, important genus. A member of the huge Bean Family, the genus Phaseolus is recognized by its trifoliate leaves (with three leaflets, like clover); by the flower's style (the ovary's "neck") being hairy, or "bearded," toward the top, and; by the flower's keel (the two lower, grown-together petals) twisting into a spiral. You can see all that at http://www.backyardnature.net/n/11/111218ib.jpg.
This being a Bean Family member with "papilionaceous" flowers, the two large, white petals are the "wings," the large, greenish petal is the "standard," and the strongly curved thing arising between the two wings' bases is the "keel." We discuss papilionaceous flowers at http://www.backyardnature.net/fl_beans.htm.
So, at the outer end of the spiraling keel you can barely see some white fuzz and extended white stamens. That fuzz is the style's "beard" we spoke of. Why do Phaseolus flowers have spiraling keels? When you have that question, what you do is to sit down next to a flower, wait for a pollinator, and see what happens.
The pollinators I saw landed with their legs grasping the two bottom petals, the wings, so that most of the insect's weight rested on them. As the weight levered the wings down, some kind of inner linkage with the style caused the style's tip to thrust much farther from the keel, thus becoming much more likely to be dusted with pollen. You can see a flower held between my fingers with its wings depressed and showing much more of its fuzzy style than in the first picture, at http://www.backyardnature.net/n/11/111218ic.jpg.
So, the flower seems to be engineered so that until the moment of pollination its sexual parts are mostly shielded from the elements by its coiled keel, but a pollinator's weight causes those sexual parts to be thrust forward where they're more accessible for pollination.
DWARF BANANA FLOWERS
The common Banana plant, sometimes known as the Plantain, is usually named Musa paradisiaca, and under ideal conditions it can grow up to 30 feet tall (9m). Here we also grow Dwarf Bananas, often known as MUSA NANA, which are much smaller. You can see some
in our garden, with me peeping from the shadows, at http://www.backyardnature.net/n/11/111218ba.jpg.
Some of our Dwarf Bananas are just issuing new flower spikes so near the ground that their flowers are easy to see. An emerging spike with female flowers at the base ready for pollination, and male flowers at the top still enclosed in large, purplish bracts, is shown at http://www.backyardnature.net/n/11/111218bf.jpg.
The yellow-green, banana-shaped items at the picture's bottom are the female flowers' ovaries, which eventually will ripen into bananas. The white, papery, cuplike things atop each ovary are calyxes. Corollas are represented by single petals, which aren't distinguishable in the picture. The matchstick-like items jutting from inside the calyxes are globular stigmas atop their styles, which are the ovaries' necks. A close-up better showing the female flowers is at http://www.backyardnature.net/n/11/111218bg.jpg.
One story the above picture tells us is that bananas employ the strategy of having their male and female flowers mature at different times. While the female flowers are in plain view, the male flowers remain hidden behind large, reddish-brown bracts, not yet mature and not yet producing pollen.
Actually, this neat trick for avoiding self-pollination is wasted on bananas, since they've been so single-mindedly selectively bred by humans for so long that under normal conditions banana plants have lost their ability to reproduce sexually. When you slice a banana and see those tiny, dark, sandgrain- like items in the fruit's core, you're seeing aborted ovules. Banana trees are reproduced by offshoots, not seeds. If humans disappear, banana plants will, too.
By the way, with such scrambled genes, banana taxonomy is a mess. Some top experts say that the whole Linnaean concept of the binomial consisting of the genus and species names is inadequate to deal with the banana's heritage. Still, the USDA declares that the Banana Family, the Musaceae, comprises two genera, and the banana genus Musa embraces seven species. Some banana species produce seeds in inedible fruits, and some species are important fiber producers.
Another aside: How do you distinguish a Dwarf Banana from small cultivars of the regular Banana? My old Bailey's Manual states that, among other things, the Dwarf's calyx is 1-1¼ inches long (2.5-3.2cm) while the regular's is 1½-2 inches (3.8-5.0cm). Ours is one inch. Also, the large scales covering a Dwarf's male flowers are "red-brown," while the regular's are "red or violet." Ours could be called red-brown. Therefore: Dwarf.
LATE DECEMBER LIGHT
Late this Wednesday night, December 21, the Winter Solstice takes place in central and western North America; in North America's Eastern Time Zone and Western Europe it occurs early Thursday. Therefore, it's not surprising that sunlight these days presents a special feeling.
During recent weeks if you stood outside in late afternoon paying attention to the light's wateriness, the shadows' black, sharp edges, and the air's feeling of things being shifted a bit to one side... you could sense the annual cycle closing down, the specialness in the moment, even this far south in the tropics. I know the feeling is much more pronounced farther north, but it's strong here, too.
It's a shame so many festivities take place nowadays distracting from this majestic ending of the Earth's most important cycle, and the beginning of a new one. During the Winter Solstice I feel more out of step with my native culture than at any other time. Some Maya, the shamans mostly, do celebrate the Solstice in their own way, though usually their date doesn't coincide with mine. And, really, I can't relate with their chants, drinking the balché and offering it to the four directions, the billowing copal incense. Most Winter Solstices, I don't say a word to anyone about it, just keep it in my own head and try to maintain a certain sense of decorum, celebration and reverence the whole day.
This time next year, though, many will be focusing on the Winter Solstice because of all the media hype about the Maya saying that the world will end then. Of course the Maya don't say that at all. According to one stone slab, or stela, the Mayan Long Count, which began in 3114 BC -- long before any identifiable Maya culture came into being -- ends. But the Maya don't say what happens on that date, other than that another count begins. The whole issue is discussed at http://www.archaeology.org/0911/2012/ .
During the Solstice, the important thing is to look around and see and feel what's in the light, the air, the web of living things gracing that exact moment, and to celebrate it as the new cycle reveals itself, a cycle taking place within another cycle in which the Earth has come into being, has evolved and brought life to a certain point, and now... what... ?
Such magnificence, such mystery...
Late Wednesday night the Earth's and Life-on-Earth's own special moment comes and I inside my mosquito net will give a silent, unseen nod to the whole shebang.
Best wishes to all Newsletter readers,
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