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

December 6, 2015

STRANGE GOINGS-ON IN THE ORGANIC GARDEN
On a visit to Hacienda Chichen's organic garden I found my friends Paulino and Pedro busy working at something that at first I couldn't figure out. See if you can, at http://www.backyardnature.net/n/15/151206tz.jpg.

They were carefully spreading large Hoja Santa leaves atop a hole in the ground large enough to drop a put your fist in. A similar hole is at the picture's bottom, right corner. Atop the leaves they then arranged several parallel sticks so that they covered the hole's mouth. Then a light coverning of loose, granular soil was spread atop the whole thing, hiding the sticks and leaves. That's when the above picture was taken.

After taking all this in I began noticing that a tree sapling was bent over so that its top passed over the hole, and that from the sapling's trunk two white strings passed through the soil, sticks and leaves. One of the strings was very taut, the other loose.

Before I could analyze the situation, Paulino explained that they were building a Tuza trap, Tuzas being a kind of pocket gopher common in the Yucatan. You can see one with nice shots of its pockets and claws on our Tuza Page at http://www.backyardnature.net/yucatan/tuza.htm.

So, here's how the trap works:

First, you have to know that Tuzas dig extensive networks of horizontal, subterranean tunnels, with vertical exit and entry holes here and there. The two string pass through the leaves, sticks and dirt, and down the center of a vertical Tuza hole. In the picture, the bent-over sapling is held down by the taut string, which is held in place by a stake that has been driven into the ground at the bottom and in the center of the hole.

The loosely hanging string has a wire noose at its end. The noose's opening has been pressed into the tunnel's walls at the bottom of the vertical shaft so that the Tuza navigating his horizontal tunnel has to pass through the noose. However, half a finger's length beyond the noose the taught string attached to the stake driven into the tunnel floor bars the Tuza's pasage -- so really only the Tuza's head passes through the noose.

So, there the Tuza is with the noose surreptitiously around his neck, and the knowledge that he can easily gnaw through such rootlike obstacles as that taut string barring his way, so he starts gnawing. When the string breaks, the bent-over sapling held in place by the taut string instantly jerks upright with great force. However, the sapling rises only a little, because now the previously loose string with the wire noose at its end comes into play. The noose in a flash closes hard around the Tusa, and yanks him upward with great force.

But, the noose can't go far, because its string passes between two parallel, close-together poles shallowly buried in the ground and crossing the top of the Tuza's tunnel, just beneath the roof of leaves, sticks and dirt. And those poles don't give way because their ends are anchored in place by the large limestone rocks shown in the picture on both sides of the hole. The jerked-up Tuza's body, therefore, slams into the barrier created by the two buried poles, and is kept there with all the force of the sapling, which hasn't by any means returned to its natural position. The wire noose pulled so hard around the Tuza's body closes so narrowly that the Tuza can't breathe, and dies.

I like Tuzas, but can sympathize with my friends' position, for they have worked hard to establish a small banana plantation at the garden, and the Tuzas are beginning to enter the area and disturb the banana plants' roots. Actually, Paulino and Pedro are taking a special organic-garden approach to dealing with their Tuzas, for the Maya certainly know how to wipe out a population simply and easily by dropping poisoned corn grains down their holes.

I have Tuzas around the hut, too, but for me they provide a valuable service, as you can see at http://www.backyardnature.net/n/15/151206ta.jpg.

That picture shows two or three bushels of black, organic-matter-rich, nice and crumbly soil perfect to use as potting soil, mounded around the base of a Spanish Plum tree. And that soil has been left there by Tuzas. The depressions on the mound's near side are where I've removed potting soil.

Of course, Tuzas also do Nature a service by loosening up the soil and keeping it from becoming so compacted that rainwater can't soak in well. Their tunnels provide air ducts that conduct air underground into areas away from their holes. And soil air is as important as soil moisture, for most soil organisms need oxygen as much as we do.

*****

TUFTED-SKIPPER ON THE COMPOST
It's been awhile since a new species has been added to our Selected Butterflies of the Yucatán Page, though it's not because I haven't been looking for them. Our Yucatan Butterfly Page is at http://www.backyardnature.net/yucatan/mariposa/index.htm

New ones are just hard to find. However, this week as I was peeing on the compost heap, something unmistakably new turned up right below me, clearly liking something he'd found there. You can see the woolly-winged critter at http://www.backyardnature.net/n/15/151206sk.jpg.

With that thick body, hooked antennae and a tendency to hold the wings lower than most butterflies, this was obviously of that large butterfly group known as skippers. Skippers tend to be less colorful than other butterflies, often being mottled brown and gray, but this one's broad, brilliantly white splotches set it apart. When I sent the image to volunteer identifier Bea in wintry Ontario, quickly she replied "Oh boy! Oh boy! A new mariposa!" the word mariposa in Spanish meaning butterfly.

Bea says that it looks like the Cleat Tufted-Skipper, POLYCTOR CLEAT, occurring from Mexico south to Costa Rica.

Normally when Bea sends a name I'm able to find interesting information about it on the Internet. However, after lots of Googling, I can report that not much information is available about the species. Several pictures of it are posted here and there but usually only the location where the pictures were taken is provided, and sometimes not even that.

So, by reporting here that our Cleat Tufted-Skipper was found on a compost heap in central Yucatán in early December, at the edge of a secondary forest with a mixture of perennial and seasonally deciduous trees, maybe we're increasing what's known about this species a great deal.

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SNOW SQUARESTEM
Some of the least presuming, downright homely looking plants turn out to be -- when you take the time to pay attention -- very interesting and pretty. That's the case with the leggy, gangly weed growing beside the road between Pisté and Xcalacoop shown at http://www.backyardnature.net/n/15/151206ss.jpg.

Up close, the plant takes on a little character with ts leaves, the larger ones all clustered at the plant's base, bearing saw-toothed margins and one or two spreading lobes at their bases, as shown at http://www.backyardnature.net/n/15/151206st.jpg.

What appear to be white flowers at a distance, up close prove to be mothball-size heads consisting of many tiny, white, cylindrical flowers, or florets, each mature floret topped with two style arms curving up and out of the corolla, like bull horns, as seen at http://www.backyardnature.net/n/15/151206su.jpg.

This manner of packing tiny florets into a head tells us that we're dealing with a member of the Composite or Daisy Family, the Asteraceae. Once we realize that, and remember that the Composite Family is one of the two or three most species-rich of all plant families, and that figuring out the species can be hard, we know we need to start paying attention to details.

The first big field mark to note is that the florets in this species are all of the cylindrical "disc flower" type -- no ray flowers. Most Composite Family species have both disc and ray types, such as asters, and many produce only ray types, such as dandelions, so already we know we're dealing with that minority of Composite Family members whose flowering heads bear only disc flowers.

Another important field mark needed for Composite Family identification usually is the shape and configuration of the green, cup-like "involucres" below the cluster of florets, involucres being composed of modified leaves called phyllaries, which usually are triangular, sharp-pointed and arranged into one to several series, as shown at http://www.backyardnature.net/n/15/151206sv.jpg.

In that picture, the involucre is more or less "normal," but it's worth noting that inside the corolla tubes there are black anthers; most anthers are yellowish, like pollen. More important field marks are shown in a broken-open head in which the corollas have fallen off and the florets' ovaries have developed into hard, dark, cypsela-type fruits, seen at http://www.backyardnature.net/n/15/151206sw.jpg.

First it's important tonote that between each sunflower-seed-like fruit there's a papery, pale brown, fingernail-like structure partially enveloping the fruit. Those are "paleae," and in the Composite Family thousands of species produce flowers with them, while thousands lack them, so this is one of the fundamental things we need to know. Another important field mark is that the cypselae fruits aren't topped with white hairs as dandelion and aster cypselae are, nor with permanent spines like those of Spanish-needles or Stick-tights.

We've already seen enough to figure out this plant, but one more nice detail worth showing is that once all its cypselae have fallen away, the papery paleae subtending the head spread out, making what looks like a handsome little flower with many whitish petals, as seen at http://www.backyardnature.net/n/15/151206sx.jpg.

This is MELANTHERA NIVEA, distributed from the US southeastern states south through Mexico, Central America and the Caribbean to Brazil in South America. Occurring in the US, it's been bestowed with the English name Snow Squarestem. In Spanish it's often less elegantly known as Yerba de Cabra, or Goat-plant.

Despite its homeliness, gardeners in the southern US are beginning to esteem Snow Squarestem. An information sheet available online from the Florida Native Plant Society describes the plant as a must for any butterfly garden because of the copious nectar it supplies to pollinators, plus its herbage hosts caterpillars of certain butterfly species. "This species will keep your garden humming," they write.

*****

BONEBRACT
Along the entrance road to Hacienda Chichen, a population of yellow-flowered members of the Composite or Daisy Family, the Asteraceae, was putting on a pretty show clambering over limestone rocks. I stopped to admire them, even though from the road they looked like ordinary Spanish-needle-like fall weeds, as you can see at http://www.backyardnature.net/n/15/151206bb.jpg.

Up close, the individual flowering heads were attractive but humdrum in appearance, still reminiscent of ubiquitous Spanish-needles, as shown at http://www.backyardnature.net/n/15/151206bc.jpg.

However, the moment I stooped for a side view of the head, it was clear that here was something interesting, something I may not have seen before. That view is shown at http://www.backyardnature.net/n/15/151206bd.jpg.

Two field marks are attention getting here: First, the green, bowl-shaped structure from which the yellow florets arise, the "involucre," consists of only five leafy "phyllaries" affixed side by side instead of overlapping as they do in most composite flowering heads. Second, the yellow, petal-like ray flowers radiating from the cluster's center narrow at their bases into long stem-like structures, and that's unusual. Pulling down one side of the involucre one of the flower's hidden secrets awaited, as displayed at http://www.backyardnature.net/n/15/151206be.jpg.

Not only do the big, radiating ray flowers narrow at their bases into stem-like structures, but the "stems"also attach to their own small, green, stem-like structures which, given their position below the corollas, can be nothing but sterile ovaries modified to take on stem duty. In other words, the ray flowers in this species don't produce fruits; they're just there to attract pollinators.

In the above picture, to the left of the small, slender,sterile, ray-flower ovary, notice the much larger, green, hairy ovary from one of the head's interior disc flowers. But, about that big ovary bulging out over the ray flower's shriveled one... It shouldn't be green and hairy. Composite flower ovaries are normally black or white, and not so hairy. A closer look at ovaries in one of this plant's heads that was mature enough for the ray and disc flowers to have fallen away is shown at http://www.backyardnature.net/n/15/151206bf.jpg.

The green, hairy, spherical things that until now have been called ovaries bear at their tops low, lopsided, collar-like affairs, which is even more mysterious.

The breakthrough came with noticing something in the above picture's lower, right corner. From behind the collar-like thing atop the green, hairy, and even warty, spherical item it looks like there's something hairless barely peeping from behind the collar. In other words, in this species the green, hairy and warty part is a special scale enshrouding the normal ovary.

Our pretty roadside weed is SCLEROCARPUS DIVARICATUS, the genus Sclerocarpus embracing eight species, seven of which occur in Mexico, making this the center of the genus's evolution. Species of the genus Sclerocarpus often are known in English as bonebracts, because when the fruits and bracts surrounding them are mature they're "hard as bone."

The bracts in "bonebract" are "paleae," which we've met in other species, but in this case they have enlarged into bag-like coverings completely enveloping each of the flower's cypsela-type fruits. Such a covering of an ovary or fruit is known as a "perigynium," and the mature, cypsela-type fruit enclosed within its perigynium is known as a "sclerocarp."

Another Sclerocarpus species, Sclerocarpus uniserialis, is much better known because it's more widely distributed and commoner, even occurring in Texas. I had problems distinguishing the two species until on the Internet a 2011 study turned up by José Luis Villaseñor and Óscar Hinojosa-Espinosa entitled "El género Sclerocarpus (Asteraceae, Heliantheae) en México." Appearing in the online Revista mexicana de biodiversidad, it's freely available. That paper makes clear that among other details distinguishing Sclerocarpus divaricatus the five green phyllaries subtending the heads are much broader than in other species.

Sclerocarpus divaricatus occurs in a broad range of habitats from central Mexico south through Central America into northern South America. I can't find mention of any particular use for it. It's just one of those many overlooked, mostly unknown species Nature has populated the Earth with, apparently satisfying Nature's impulse to generate curious adaptations and special features wherever and whenever possible.

*****

ESCOBILLA FRUITING
Groping toward a gravel road's sunlight, a slender branch bearing twice-compound leaves emerged from the dense forest wall bearing a six-inch long (15cm), legume-type fruit, as shown at http://www.backyardnature.net/n/15/151206zp.jpg.

The legume was unusual in that not only did it narrow at its base into a slender stem, but also this stem itself was attached to another fairly long stem. Clearly the plant "wanted" its legume to extend beyond its leaves, and maybe dangle on branches which, at least along the road, dangled from tall trees. In better light you can see that the legume is fairly unusual looking, at http://www.backyardnature.net/n/15/151206zq.jpg.

Noticed how the beans inside the pod sometimes are separated from one another, and that the pod's margins are conspicuously thickened. At the above picture's top, left corner, you can also see a short, curved back spine.

Despite not having flowers, the pod and leaves were so distinctive that it was easy to figure out that here we have what's often called in Spanish Escobilla, meaning "little broom." It's ZAPOTECA FORMOSA, a member of the Bean Family, as its legumes, beans and acacia-like, twice-compound leaves indicate. No flowers are visible at this season. I read that the fruits are "explosive," in that when the ripe legume dries out, great outward stress forms tugging the walls apart, but the legume's thick margins keep the walls together until the stress is very great, and the walls snap open, throwing beans in all direcitons.

Escobilla is fairly common in weedy, disturbed woods, especially those in somewhat arid climates, all the way from Arizona in the US and northern Mexico to Argentina in South America. With such a large distribution it's fragmented into at least six recognizable subspecies.

This is another of those species that is basically a tree, but it likes to lean on other vegetation and often tends toward being a vine. The way it dangled from the side of the roadcut through the forest, as first I thought it was a vine. Its curved, short spines help the plant snag on stronger limbs. In our forests here we have several such leaning and clambering tree species, and I've often wondered whether this may be an adaptation to our hurricanes. When strong winds hit our area, Escobilla will be one tree that won't snap. It'll bend, and if all the other trees fall, it'll grow over them.

*****

MOLD ON A LOG
This week the weather has been about perfect, not too hot, not too chilly, and only an occasional little sprinkle in the afternoons. Normally it's good to have a rain every few days but here at the end of the rainy season there's such lush greenness that we're ready for fall-type wildflowers to add their yellows and white to the roadsides, and it'd be good for things to dry out a little.

Different from most of the year, this is a good time to see fungi, most of which need high humidity. For example, look at the white, moldy spots on a log that's been lying in the shade next to my hut at http://www.backyardnature.net/n/15/151206md.jpg.

In that picture, in the top, right corner, along the log's lower side, notice how the white material appears to be suspended atop many slender filaments. A close-up of part of that population is shown at http://www.backyardnature.net/n/15/151206me.jpg.

That enchanted forest of fungus shows a kind of Ascomycetes fungus reproducing asexually. To start understanding that, first we might recall that in the forest sometimes when we separate two plastered-together leaves on the forest floor we find white thread-like filaments fanning across the blades' surfaces. Those white filaments are the bodies of fungi soaking up moisture and nutrients from the decomposing leave's surfaces, and they're known as hyphae (singular hypha). Mushrooms are formed from underground hyphae and are the hyphae's fruiting bodies, not the main fungus. The fungus's "body" is the network of hyphae.

Knowing what hyphae are, we can say that in the enchanted forest picture the trunk of each "tree" is a special kind of hypha called a conidiophore, the word conidiophore just meaning "bearer of conidia." And conidia are basically microscopic bits of hyphae that break off or bud from the tips of hyphae bodies, with no sexual activity involved. When conidia are transported -- usually by wind -- to moist and otherwise favorable environments, they grow into regular hyphae.

After taking the enchanted forest picture I blew a puff of air onto the forest, and a white cloud burst from it and drifted on a breeze into the real forest beside us. The cloud consisted of untold thousands of microscopic conidia budded from the tips of the many branches visible in the picture. This is how fungi can turn up in so many places seemingly spontaneously, for the air -- especially our soggy, late-rainy-season air -- is simply loaded with conidia.

About 1,500 genera of conidia-producing fungi are recognized, and some 30,000 species of them have been described, with these numbers increasing rapidly, so you might guess that I can't identify the species in our photos. Technically, we can say that our enchanted forest pictures show "columnar aggregations of synnematal conidiomata," so maybe with those key words appearing in this writing, some future, search-engine-using specialist with find our report, and identify our fungus for us.

*****

MOLDY BINOCULARS
In this greenhouse-like air, decaying logs aren't the only places white mold shows up. This week I wanted to look at a bird but when I retrieved my binoculars from the hut, where they'd hung unused for about two weeks, they were in the condition shown at http://www.backyardnature.net/n/15/151206bi.jpg.

That's white mold, or fungus, dusting them, and notice that the mold even extends onto the glass lenses.

Because white mold is so common and often destructive, entire websites are dedicated just to white mold. From these I learn that the types most commonly seen in homes include: Penicillium, which often appears bluish-green and white; Aspergillus, which can also appear yellow or green, and; Cladosporium.

Despite the fact that interesting bird migrants are still filtering in after journeying from the North's approaching winter, my binoculars had been hanging unused on a wall in the hut for two weeks because they have become practically useless. Images seen through them appear to be viewed through thick oil -- dim and with pale halos. I assume that this is caused by many years of accumulated fungus damage to the surfaces of lenses and prisms, both inside the binoculars and out. Here in the humid tropics binoculars and cameras just lose their ability to form sharp images.

Mold found on glass is most likely growing on organic compounds in the lenses' coatings, not the glass itself. However, apparently when molds produce chemicals to break down organic compounds, the chemicals can etch glass, causing real damage.

You can imagine what's happening with my clothing, books... and computer.

*****

FEATURED ESSAY FROM THE PAST:

"A Month of Easter," from the March 25, 2006 Newsletter, at http://www.backyardnature.net/n/p/060325.htm

*****

Best wishes to all Newsletter readers,

Jim

All previous Newsletters are archived at http://www.backyardnature.net/n/.