March 19, 2017
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BULLHORN ACACIA FLOWERING & FRUITING
Bullhorn acacias are species traditionally placed in the genus Acacia, but who nowadays often are put in the genus Vachellia. Their twigs bear very large, thick-based, mostly hollow spines in which ants sometimes live. Several bullhorn acacia species are recognized. We've seen the one known technically as Acacia collinsii in the forests around Chichén Itzá ruins, and the page for that species is at https://www.backyardnature.net/yucatan/acacia-t.htm
A fellow in Velbert, Germany specializing in ants wrote asking for Acacia collinsii seeds so he could grow trees in which acacia-thorn ants live. Weeks ago I found some bullhorns here on the ranch and have been waiting for the fruits to mature. This week they're maturing and if you look hard -- they're camouflaged to look like spines -- you can see the dark, pod-like fruits with pointy tips among more slender, sharper-tipped spines at https://www.backyardnature.net/n/17/170319ac.jpg
Up close you can see some pods, two of which have split open and lost their contents, at https://www.backyardnature.net/n/17/170319ad.jpg
Two split-open pods with their contents in place -- the pods matured in a cup in the hut -- are shown at https://www.backyardnature.net/n/17/170319ae.jpg
I was surprised that the black seeds (beans) developed with such a large amount of greenish pulp between them. I'm interpreting this to be an adaptation encouraging animals to eat the pulp, in the process swallowing the seeds, which later will be disseminated away from the parent tree in the animal's feces.
Both here and around Chichén Itzá mature Bullhorn Acacias not only are protected by their spines and biting ants living in those spines, but also by wasps who build paper nests on the trees' limbs, as shown on a flowering branch at https://www.backyardnature.net/n/17/170319af.jpg
The wasps in those nests do sting with the slightest provocation. As I photographed a spine with an ant entry hole I was stung twice on the back of the head. Interestingly, first the camera and my fingers were attacked, and then the top of my bald head, but no sting resulted. Then they found the hair at the back of my head and the stinging began. Maybe the wasps needed hairs for holding onto as they drove their stingers into me. Two stings caused considerable swelling that lasted several hours. The spine with an ant hole for which I paid with the stings is shown at https://www.backyardnature.net/n/17/170319ag.jpg
We've already seen the Bullhorn's tiny, yellowish packages of protein called Beltian bodies, which grow at the tips of young leaflets. Ants eat the bodies. This week I got an even nicer picture of the bodies, shown at https://www.backyardnature.net/n/17/170319ah.jpg
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COPPICING WILD TAMARIND
At https://www.backyardnature.net/mexnat/leucaena.htm we meet the Wild Tamarind, locally called Uaxim in Maya, which may be the Yucatan's most common tree. It's so abundant because it thrives in disturbed habitats such as roadsides, abandoned fields and below power lines. On our Wild Tamarind page we mention that the Maya often cut the tree's young branches to feed to livestock -- young stems and leaves. Often along the highway you see local men who have come on their bicycles or even in taxis to cut large bundles of Wild Tamarind for their livestock. Even pigs eat it.
Near Ek Balam recently some men set about cutting a large area of forest, leaving only the scattered trunks of decapitated small trees. Very soon these trunks sprouted numerous sprouts, as you can see at https://www.backyardnature.net/n/17/170319cp.jpg
A close-up of some of the sprouting trunks is shown at https://www.backyardnature.net/n/17/170319cq.jpg
Now I understand that when the forest was cut the remaining lower trunks were those of Wild Tamarind trees. Apparently the trunks' sprouts are meant to supply livestock feed. During this very hot, dry season the herbaceous layer has died back, and deciduous trees have lost most or all of their leaves, so free livestock food is hard to find.
The practice of cutting back trees to encourage new growth is called coppicing, and it's an old technique currently gaining recognition around here. I've not seen it done here on such a large scale before. At the ranch our Wild Tamarinds are coppiced to encourage sprouts for the livestock, but we don't have large fields of them like this.
I have mixed feelings about the process. On the one hand, it's using a native, locally grown plant as food for livestock. On the other hand, it's converting forest composed of diverse species into a monoculture, which is ecologically unstable and not nearly as useful to wildlife as regular forest.
It's all being done to feed livestock. The most ecologically friendly approach is for people to stop eating animal flesh, and leave the forests as they are.
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PLANTING CHAYOTE
Earlier this month we looked at Chayote fruits bought in a local market, for eating. Our page for that squash-like plant is at https://www.backyardnature.net/mexnat/chayote.htm
Years ago a young Maya man taught me how to plant Chayote in the garden, and our Chayote page has shown how he did it. I've removed that section because now I think he didn't know how to do it himself. That's not too surprising since most young Maya pay little attention to the old ways and don't care much about growing their own food. The reason I doubt the young man knew what he was doing is because he planted his fruits with the "tongue" pointed skyward, the idea being that the "tongue" was the emerging young plant.
But, the "tongue" was something else, as I learned when some of the Chayote fruits written about earlier remained uneaten in their crate so long that they began to issue roots and sprouts, as shown at https://www.backyardnature.net/n/17/170319ch.jpg
In that picture the ascending, green stem is the future vine, the "epicotyl," while the descending white items are roots. Both epicotyl and roots are issuing from between the "lips" of the "tongue" the young gardener had planted facing skyward. That being the case, the protruding "lips" are the tops of the plant's two first leaves, the cotyledons, so the "tongue" is just the two cotyledon tips pressed together.
When seeds of certain species germinate, such as those of the common garden bean, the two cotyledons are pulled from the seed coat and carried above-ground atop the elongating stem, or hypocotyl. This is called "epigeal germination." In other seeds, such as peas, the cotyledons remain within the seed coat while the embryonic stem, or "epicotyl," rises above-ground. This is called "hypogeal germination." On our germinating Chayote fruit the cotyledons clearly are staying in place below-ground, so Chayote fruits practice hypogeal germination.
Therefore, I planted my chayote fruits on their sides just below the soil's surface, so that the soil's moisture would encourage root growth. After just a couple of days most stems already had issued from the soil. You can see an inch-tall sprout (2.5cm) with the vine's first leaves preparing to unfurl at https://www.backyardnature.net/n/17/170319ci.jpg
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AFTERNOON CLOUDS
Nowadays as the dry season weighs ever heavier on the land and we approach the hottest month of May, most early mornings are cloudless and the skies deep blue. By late morning white, cottony cumulus clouds float peacefully in the blue. As the afternoon progresses, clouds grow in number and size, the blueness pales, and by 2PM the thermometer in the porch's shade reads 95-100°F (35-38°C). That's a good time for sitting still and looking around. Often, I look at clouds.
Clouds can be thought about in all kinds of ways, but these days my mind has been flitting around one certain notion. That is, that always the sky's air is occupied with molecules of water, but we don't see the water until its molecules condense into clouds. In other words, we don't notice the water until its molecules rearrange themselves into patterns more complex than general diffusion.
What's interesting about this formula of increasing complexity of pattern leading to a more noticeable phenomenon is that it takes into account an observer who notices.
Of course, it's a child's belief that clouds might form in a summery afternoon sky at least partly to be admired by an observer such as myself. However, in a Universe where the same Creative Impulse creates both clouds and child, is the thought to be rejected off-handedly?
In fact, now in my gray-beard days, afternoon clouds set my thoughts dancing around a certain irrational and unprovable, but very appealing, idea, one as agreeable as a mid-afternoon breeze. Here it is:
There's just one observer to everything -- everything -- and what's observed is being magically conducted from an infinity of nerve-ending-like sensors -- sensors like you and me -- to the single Universal Consciousness.
Are you and I not like taste buds on the Universal Observer's tongue?
And, doesn't this concept suggest that it might be OK for a fellow to sit around on a hot, tropical-dry-season afternoon doing nothing but admiring clouds, and feeling glad for any friendly breeze that comes along?
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Best wishes to all Newsletter readers,
Jim
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