February 1, 2019
*****
"CLIMBING STICK-TIGHTS"
During this season when most trees slowly are losing their leaves because of the advancing dry season, right beside the hut in which I live a vine has begun flowering. You can see dispersed clusters of the yellow blossoms exactly as I see them as I type this at https://www.backyardnature.net/n/19/190201bi.jpg
Up close it's clear that this is a member of the huge Composite/Aster/Sunflower Family, the Asteraceae, because flower-like heads consist of several tiny individual flowers, as shown at https://www.backyardnature.net/n/19/190201bj.jpg
North American wildflower fanciers will recognize both the pinnate leaves and the flowers as similar to what's variously called stick-tights, Spanish needles, or tickseeds. In the fall, stick-tights sometimes turn roadsides and entire weedy fields yellow with their blossoms,, and when you walk through them your clothes end up carrying dark, little tick-like items hanging on with tiny, barbed, needle-like spines. Several species go by that name, but typically when we use those names we're referring to members of the genus Bidens. Moreover, in the above picture you can see certain "needles" projecting from flower clusters. It really looks like a Bidens, but Bidens species are supposed to be wildflowers or weeds, not vines climbing in trees...
Up closer, the flowering heads look even more like they belong on knee-high stick-tight plants, as shown at https://www.backyardnature.net/n/19/190201bk.jpg
The collection of green bracts, or the "involucre," subtending each flower head of species in the genus Bidens do something special. The bottom-most ones are thick and green while the upper or inner ones are thinner and often paler. Our hut-side vine's involucral bracts match that description, as seen at https://www.backyardnature.net/n/19/190201bl.jpg
That observation sends us looking for more indications that this is actually a climbing, viny stick-tight, a Bidens, because, at least to a northerner, that would be surprising. In the genus Bidens the petal-like ray flowers issuing from the sides of the flower heads can be yellow or white, and ours are yellow. The tiny, closely-packed, cylindrical disc flowers in the heads' centers are yellow, and our vine's disc flowers are yellow, too, as seen at https://www.backyardnature.net/n/19/190201bm.jpg
In that picture the dark brown items are pollen-producing anthers fused along their sides, forming a cylinder around each the style, atop which two yellow stigmas emerge and become Y-shaped. Stigmas are where pollen grains from other flowers land, germinate, and send their male sex germs down through the style to the ovary at the flower's bottom, and that ovary then will mature into a one-seeded fruit. If you break away one side of the flower head you can see what's shown at https://www.backyardnature.net/n/19/190201bn.jpg
At the right in that picture a disc flower has pulled away clearly showing the yellow corolla atop the ovary, which already is taking the form of a typical stick-tight of the genus Bidens. See the two upward-projecting, barbed "needles" that later will so stubbornly stick to your trousers or hairy legs? A last picture showing details of one of the vining stem's nodes -- where leaves and sprouts arise -- appears at https://www.backyardnature.net/n/19/190201bo.jpg
So, our vine is indeed a climbing stick-tight. It's BIDENS SQUARROSA, generally distributed throughout the American tropics. It has no commonly used English name, so our name "climbing stick-tight" is a made-up one, just for us. But English speakers need such a name so they can talk about this climbing Bidens, and ask one another what a vine needs such needle-bearing stick-tights for up in the air where no trouser legs or hairy legs go wandering through. Squirrels, bats, monkeys, kinkajous... ?
As I type this many bees buzz around our climbing stick-tight's flowers, so I know that what Juan told me is true, that this is an important plant for them.
Also, online I see that in 2008 MC Pérez-Amador and others published an article in the journal Phyton (B. Aires) on the biological activity of phototoxic compounds in Bidens squarrosa. Our plant was chosen because it had not been studied, despite the fact that leaf infusions made from other species of the genus Bidens have been used traditionally to treat influenza, swollen and sore throat, and dysentery. They found that extracts of Bidens squarrosa showed significant antibacterial and antiinflammatory activity, deciding that "Results obtained in this study validate the use of Bidens squarrosa as a medicinal plant."
*****
FIGURING OUT AN IMMATURE VINE
Amid weedy brush next to the corral several hand-size leaves caught my attention because I'd not seen leaves exactly like these. They're shown at https://www.backyardnature.net/n/19/190201s5.jpg
Near that picture's bottom-left corner you can see that the leaves arise opposite one another on a slender, pliable-looking stem. Most plant families produce leaves alternating with one another on the stem, so that simple field mark helps eliminate possible species in many plant families. Also, the stem is so slender that the plant must be a vine. The stem climbed onto a strand of barbed wire, then at a tree trunk the wire was nailed to began wrapping itself around the trunk and growing upward, as shown at https://www.backyardnature.net/n/19/190201s6.jpg
Most plant families don't produce vines, so this also drastically limited the number of plant families we could be dealing with. Following the vine upward brought me to where the vine's leaves were just beginning to unfold, and those leaves showed some peculiarities, as seen at https://www.backyardnature.net/n/19/190201s7.jpg
Note how leaf lobe tips narrow to form curling, hairlike appendages, which I'm guessing might hold immature leaves in place when the vine climbs inside dense brush. The leaf blade is white with very slender, silky, close-lying hairs, a condition known as being "sericeous." Also, at the blade's bottom, where it connects to its petiole, notice the two green glands.
At the elongating vine's tip, where tiny leaf blades were just forming and hardly recognizable, the curly hairs that eventually would arise from the lobes' tips already were well developed, and so were the green glands at the future petioles' bases. And ants gathered there, maybe to drink secretions produced by the glands. All this can be seen at https://www.backyardnature.net/n/19/190201s8.jpg
A close-up of a liquid-issuing gland on a fully developed leaf is shown at https://www.backyardnature.net/n/19/190201s9.jpg
In that picture brown, close-lying hairs cover both the leaf blade and the petiole. The oldest stems where the vine was rooted were mostly hairless, but mature stems a few feet from that point also were densely mantled with similar close-fitting, brown hairs. A picture of a hairy stem node with hairy leaf petioles jutting toward the image's top and bottom is shown at https://www.backyardnature.net/n/19/190201s4.jpg
By now I'd decided which family this vine must belong to, mostly because such glands conspicuously occur on flowers in the family, and the family produces many woody vines with opposite leaves. Also, often species in the family are covered with a unique kind of hair. The hair is T-shaped, the T's vertical column being so short that the horizontal bar lies very close to the plant's surface. I looked for such hairs, suspecting that most or all the brown hairs were such T-shaped ones, just that they lay so close to the surface that they looked like they must be rooted at one end. Finally I found a single hair that was unmistakably T-shaped. Pushing my little camera to its limits, I got the picture of that hair shown at https://www.backyardnature.net/n/19/190201s3.jpg
Such T-shaped hairs in technical literature sometimes are referred to as "malpighious," because they are typical of the tropical Malpighia Family, the Malpighiaceae, which our vine belongs to.
With that, it was a matter of checking which species in the Malpighia Family found in this area produce young leaves of the kind shown here. I was led to a woody vine, or liana, often noticed here when it's fruiting and flowering, Stigmaphyllon lindenianum, on whose page you can see green glands similar to those seen here, but on the calyxes of flowers and fruits. That page is at https://www.backyardnature.net/mexnat/stigmaph.htm
On that page you can see that leaves produced later are not lobed like these young ones. Whatever the reason for have deeply lobed leaves early during the vine's development, and rounded leaves later on, it must be important, because producing two forms of leaf on one plant represents a good bit of evolutionary experimentation and refinement of genetic coding.
*****
RHYNCHOLAELIA (BRASSAVOLA) ORCHID
Some Canadian friends are retiring in Valladolid about 20kms south of the rancho, have bought a house there, and they invited me to come see their new home. Last week, in town for a new set of bifocals, I dropped by. Their address led to a door in an uninspiring wall looming above a narrow, broken-up sidewalk along a narrow, hot, dusty, potholed street. Passing through the door, however, I entered a little paradise. It was cool and lushly green, mostly a garden with a fountain and pathways winding among tall trees, flowering bushes and ornamental ground-cover, and all kinds of potted plants, and vines, and ferns, bromeliads and orchids on tree trunks and among lower branches. Around the garden's perimeter buildings, some with entire walls opening into the garden, provided elegant living for my friends.
During my guided tour a spectacularly flowering orchid rooted on a tree trunk caught my eye. It's shown at https://www.backyardnature.net/n/19/190201ba.jpg
That picture shows a good field mark for identifying tree-growing or epiphytic orchids in general, and that is the white roots adhering to but no parasitizing the trunk. The white, spongy, water-absorbing material covering the roots is called "velamen." Anatomically velamen can be thought of as a root's much modified, spongy epidermis. Its main purpose is to wick water from the air, but also it serves as insulation.
The most spectacular feature in the picture, however, is the large blossom with its white-hairy corolla lip. You can see just how large the flower is compared to my hand, at https://www.backyardnature.net/n/19/190201bb.jpg
Orchid floral anatomy is unique and can be hard to interpret. In that picture three of the long, narrow items extending outward are sepals, two are lateral petals, and the large, fringed item is the petal known as the lip. The lip curls around the "column," which is the Orchid Family's most unusual feature. It consists of male stamens and female style and stigmas all fused together. You can see the column at the top of the lip's opening at https://www.backyardnature.net/n/19/190201bc.jpg
This orchid's stem and leaves also exhibited features important for identification, shown at https://www.backyardnature.net/n/19/190201bd.jpg
Notice how the broad leaf blades at their bases abruptly connect with more slender sections, which themselves sprout from trunk-hugging, root-issuing stems. The slender sections immediately below the leaf blades are "pseudobulbs." During the dry season the blades may shrivel and fall off, leaving their pseudobulb behind. In many species the pseudobulbs are much larger than these and serve as water-storage reservoirs, and I'm guessing that these may do that as well.
All these details led to a cluster of orchid genera sometimes known as the Cattleya Alliance, Cattleya being an important genus. Our Valladolid species, easy to determine because of its spectacularly fringe-margined lip, currently is called RHYNCHOLAELIA DIGBYANA. However, that name has only recently been changed from Brassavola digbyana, and on the Internet mostly it's still called by that name. My old Bailey's Manual of Cultivated Plants refers to it as Laelia digbyana, so this species has been around.
Rhyncholaelia digbyana seems to have no good English name. It's native from southern Mexico (but not the arid Yucatan) south to Costa Rica. Despite its limited distribution, in the world of orchid-growing, it's thought of as an important species because it's so often used as a parent when producing hybrids with other species in the Cattleya Alliance. These hybrid offspring often turn out to be very vigorous growers with exceptionally large, fragrant blossoms. The general shape and fringed lip are dominant characters passed on to most hybrid offspring.
Rhyncholaelia digbyana is the national flower of Honduras.
*****
GUATEMALAN CLIMBING CACTUS, IN CHIAPAS
Last October 5th, during my camping trip into Mexico's southernmost state, Chiapas, climbing on a tree trunk beside the entry road to the ruins in Palenque National Park, a cactus issued flat, tongue-shaped blades with crenelated margins but no spines or tiny, spinelike "glochids," as shown at https://www.backyardnature.net/n/19/190201er.jpg
Apparently the flowering season had just passed, for two or three blades bore the limp remains of corollas atop ovaries just starting to enlarge into fruits, as seen at https://www.backyardnature.net/n/19/190201eq.jpg
In that picture the collapsed corolla dangles at the left. It arises from the tip of a yellowish, enlarging, fingerlike ovary, which will mature into an oblong, red, juicy fruit. An important detail to notice on the limp corolla is that what once was its slender tube is much longer than the mop of decomposing corolla lobes or petals, at the bottom.
Also in that picture the narrow, downward-pointing item at the right is an immature blade just beginning to widen, and still in the process of growing longer. Notice how it arises from a stiff, purplish, rounded stem. These stems can be fairly long, with flat blades arising intermittently along them. You can see a cluster of such drooping, blade-bearing stems, with our blossom-bearing blade visible in the picture's lower, right corner, at https://www.backyardnature.net/n/19/190201ep.jpg
Only a few cactus genera produce such flat, spineless blades on similarly long stems, and of the few that share these field marks, an important feature for determining the genus is the flower. Our wilted flower with what remains of its exceptionally slender, long corolla tube and shorter petals leads us right to the cactus genus Epiphyllum, of which 19 species are known. The name Epiphyllum celebrates the genus's peculiarity of producing flowers on the leaf -- the Greek epi, for upon, and phyllon, a leaf. Flowers upon the leaf.
Actually, such cactus blades are not leaves but rather stem segments modified to function as leaves, known as "phylloclades." But taking that into consideration, we wouldn't get such a neat name as Epiphyllum. Species of Epiphyllum often are known as climbing cacti, though several other genera also produce tree-living (epiphytic) species and go by that name.
Three or four Epiphyllum species are listed for Chiapas. Based on the size, shape and distance apart of the blade margins' scallops, or crenations, and the plant's habitat, this must be EPIPHYLLUM GUATEMALENSE, distributed from southern Mexico south through Guatemala into Honduras. I've not seen an English name for the cactus but with a species name like guatemalense, what can we call it but Guatemalan Climbing Cactus?
By the way, Epiphyllum guatemalense is the name used at the CactiGuide.Com website, with Epiphyllum phyllanthus being listed as a synonym. The online Flora of North America treats the names just the opposite, with Epiphyllum guatemalense being the synonym of Epiphyllum phyllanthus.
Little information about the species is available on the Internet, except for this: Many pages sell as a curiosity an odd-looking, twisted cultivar of the species, probably a mutation, under a variety of made-up names, Curly-locks Cactus being one of them. You can such a specimen at the GardeningKnowhow.Com website.
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WALKING WITH AUSTIN
Rancho volunteer Austin from Pennsylvania arrived with a good camera equipped with macro extensions for close-up photography, knew how to use his equipment, but needed help finding good subjects to photograph. Since I always seemed to be taking close-ups, would I give him some pointers?
Without moving from where the request was made we looked at constellations of tiny, translucent glands embedded in an orange-tree's leaf, then with a few steps came to a Cowfoot tree bearing white flowers, in which the calyx, corolla, stamens and pistil clearly could be seen, Austin particularly liking how the stalked ovary looked like a little greenbean legume. A few steps farther brought us to two plants of Ek Balam Croton with male flowers on one and female on the other.
After about an hour of this, still not far from where we started, Austi's mind percolated with new ideas about where to look, and how to think about the world between human scale and truly microscopic. He'd experienced how seeing translucent glands in an orange-tree leaf leads to new insights about plants defending themselves with chemicals. The Cowfoot flower had shown how having a mental image of "a standard blossom" can indicate what's special about any blossom encountered -- special features being those different from the "standard" one. Male and female flowers of the croton summoned thoughts aobut how Nature works hard to produce diversity by avoiding self-pollination but always building on what She already has.
Experiencing so many new insights and seeing how easily they can come about simply by paying attention, and letting one insight lead to another and another, possibly eventually bringing about some kind of transformative shift of mindset, Austin asked me what the most important effect in my life Nature study has had. I replied that my spirituality is rooted in what I've experienced and understood about Nature. And what did that mean, he wondered?
"All my life I've been groping and stumbling through the same process we just went through, trying to keep my eyes and mind open, with each new insight leading to and encouraging the next," I said. "My main compulsion for doing this was the need to have some kind of explanation for why this Universe exists, why I'm in it, and what I ought to be doing. Nature has guided me step by step, and keeps guiding me. Only a few months ago, at age 71, I finally got my thoughts about the matter together enough to articulate what I was seeing to Eric, a philosopher friend in Mérida. He identified me as a monist."
"What's that?" Austin naturally asked. I pinched my arm and replied:
"The pinch hurts. That spot of stimulated senses on my arm has an identity in that it's localized and has boundaries. It's sending reports of what the arm is feeling there to the center of intelligence, my brain, so it's useful, for the body needs to know when something is hurting it, so it can take action. Before I pinched the arm, nothing at all existed of that pain, and once the pain stops, there'll be no trace of it again. But, for awhile, that little spot of pain definitely exists, and it's important."
I let that set in, then continued, explaining that in my conservative form of monism there's just One Thing, and we entities under the impression that we're separate from other entities believing the same thing -- if they can believe at all, and of course rocks and galaxies don't seem to believe in much of anything -- are like the spot of pain in my arm.
"This pain in my arm is to me, as you and I and everything else in the Universe are to the One Thing."
Then I finished:
"I've wondered why things might be set up like this. The only answer that strikes me as halfway believable is this: We're the One Thing's nerve endings."
Austin was quick. Immediately he saw that, thinking along monistic lines, humans exist on Earth in order to experience, feel and think. Also, the monistic perspective orients us from the beginning to see how intimately all us parts of Nature are interrelated, and interdependent, and how important it is for us entities to empathize with, and take care of, one another.
*****
Best wishes to all Newsletter readers,
Jim
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