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

JULY 24, 2016

*****

AN ORNATE FRITILLARY CHRYSALIS
Deep in the forest, at about chest height, attached to bark on the lower surface of a tree trunk leaning toward sunlight, an especially pretty butterfly chrysalis "exuvia" turned up -- an exuvia being the remains of a molted arthropod such as a scorpion or an insect. It's shown at http://www.backyardnature.net/n/16/160724cs.jpg

It looked like the same kind of chrysalis exuvia we saw the other day, with a presumably just-emerged female Variegated Fritillary on it, already mating before she'd had a chance to explore her world. However, I wasn't sure of the ID, so I sent it off to volunteer identifier Bea in Ontario; she says she's pretty sure it's that species, so that's what we'll call it.

One reason I hesitated over the name is that there in deep forest where the exuvia was photographed, the forest floor was so shadowy that no wildflowers were present blossoming. Out in the fields and along roads where many plants are flowering nowadays, Variegated Fritillaries are abundant, but they're seldom seen in the forest.

*****

FUZZY CATERPILLAR UPDATE
A fuzzy, white caterpillar with curious red blotches near the head during up in deep forest this week, shown at http://www.backyardnature.net/n/16/160724cp.jpg

A close-up of the head end with its red blotches is at http://www.backyardnature.net/n/16/160724cq.jpg

Volunteer identifier Bea in Ontario thinks this must be the same caterpillar species she IDd as probably an Apatelodes species a couple of weeks ago. Just that this week's individual is much more boldly colored, as it well might be if we have a later instar. You can compare the above picture with the earlier one at http://www.backyardnature.net/mexnat/fuzzycat.htm

Interestingly, this older one just refused to expose his amber-colored head, while the younger one earlier displayed no hesitation at all.

*****

ANGLEPOD FLOWERING
During the mid dry season, in February or so, along roadsides and at woods edges, a certain vine appears here bearing conspicuous, four-inch-long pods (10 cm) on its leafless, semi-woody stems. Recognizing the vine as a member of the Milkweed Family -- now lumped into the Dogbane Family, the Apocynaceae -- with the help of a German friend who specializes in the family, back in 2010 we tentatively identified the vine as a kind of Anglepod, Macroscepis diademata. It was hard to confirm the ID because there's little solid info about that species' pods on the Internet.

This week, deep in the forest at Hacienda Chichen, the stem of a vine climbing a tree along the trail bore fairly large, stiff, brownish hairs just like those on stems we've seen bearing Anglepod pods, so here was a chance to firm up the ID, because the vine was flowering. There's much more information on the species' flowers than its pods. On this week's vine you can see large leaves and a couple of flowers arising where the leaves' petioles join the hairy stem at http://www.backyardnature.net/n/16/160724ms.jpg

At first I could only find immature flowers. A close-up showing an unopened, green corolla subtended by an unusually large, bowl-like calyx that along with the stem and petioles are truly hairy (hispid) is at http://www.backyardnature.net/n/16/160724mu.jpg

There was one open blossom, however, and it was spectacular, as shown at http://www.backyardnature.net/n/16/160724mt.jpg

Presumably the oversized sepals beneath the green corolla help attract pollinators, but if the flower wants to visually attract pollinators why are both sepals and corolla green? I couldn't smell any particular scent. You'll recognize something very distinctive about this blossom if you're familiar with the typical milkweed flower with its "gynostegium," or grown-together stigma and anthers. You can review milkweed flower anatomy at http://www.backyardnature.net/fl_milkw.htm

In our trail-side vine's blossom, the gynostegium lies flush with the throat of the flaring corolla. Normally the gynostegium rises inside a bowl-like corolla, like a pillar.

The flower definitely belongs to the Anglepod we guessed at earlier as the name for the vine producing the pods, Macroscepis diademata. Now I just need to confirm that the vines producing these flowers eventually develop the pods we've been seeing during the dry season.

Macroscepis diademata is native to southern Mexico and Central America. Other than that, there's not much information about the species available on the Internet, so maybe we're helping firm up the species' details for everyone.

*****

AN HERBACEOUS BAMBOO
With the rainy season's arrival the forest is dark and shadowy, and when an understory plant happens to be enjoying its moment in a sunbeam, it shows up as if beneath a spotlight. Such was the case with the knee-high grass shown at http://www.backyardnature.net/n/16/160724ol.jpg

Anyone familiar with North American grasses might see a resemblance between this one's broad leaves and those of the big group known as the panic grasses. However, the flowering spikelets above the vegetative parts don't look like panic grass flowers, which are spherical to oblong. This is something new for us. A closer look at the leaves is at http://www.backyardnature.net/n/16/160724om.jpg

The bases of panic grass leaves tend to partly wrap around the stem, but here the blades' bases narrow as they approach the stem and don't embrace it at all. A closer look at a leaf base shows something remarkable, a field mark seldom seen among grasses, and that's a petiole-like structure, sometimes known as a pseudopetiole, shown at http://www.backyardnature.net/n/16/160724on.jpg

In that picture the blackish pseudopetiole at its bottom fuses with the top of the sheath that wraps around the stem below the point of blade attachment. Here we also see that the ligule at the top of the sheath consists of no more than a very low, thin membrane bearing a few extremely short and fine hairs, or cilia.

At the grass's base we find remains of stiff, somewhat woody stems from previous seasons, which brings to mind the bamboos, as you can see at http://www.backyardnature.net/n/16/160724oq.jpg

Along with its unusual vegetative features, this grass's flowers, or florets, also are a little unusual, in that they are unisexual. We've come onto the grass exactly when each of its few, large female florets bears two exceptionally conspicuous, feathery styles, as shown at http://www.backyardnature.net/n/16/160724op.jpg

In that photo, the smaller florets above the large female ones are the unisexual male ones, at this moment not yet mature. Having its female flowers mature before its male ones assures that the grass's flowers don't cross pollinate.

With such peculiar and easily seen field marks, this species was easy to identify as OLYRA GLABERRIMA, found in Mexico, Central America and western South America, including Brazil. Within the Grass Family, the Poaceae, the genus Olyra falls into the Bamboo Subfamily, the Bambusoideae, and tribe Olyreae, so we can think about it as a kind of bamboo.

A 2013 paper by Scot Kelchner and others in Molecular Phylogenetics and Evolution, reporting on gene analysis of numerous members of the Bamboo Subfamily, the Bambusoideae, found that species within the subfamily tend to fall into four major groupings: temperate woody, Old World tropical (paleotropical) woody , New World Tropical (neotropical) woody, and herbaceous bamboos. Our grass in the genus Olyra is considered as a member of the herbaceous bamboo group -- despite the fact that some technical descriptions describe the species as producing woody stems.

It's hard to say where herbaceousness ends and woodiness begins, but it's clear that our Olyra glaberrima is much more herbaceous than most other bamboos.

So, who would have thought it? An herbaceous bamboo...

*****

DROPSEED GRASS
On the road to Xcalacoop sunlight glared off the white limestone-gravel roadside, such a harsh environment that hardly anything grew there at all. A certain spindly looking grass caught my eye simply because it was surviving there, and had a form I couldn't quite place. I got off the bike and took it's picture, so you can see it right beside the asphalt, which shows up as a black frame at the picture's left, at http://www.backyardnature.net/n/16/160724sp.jpg

The grass was past its peak flowering time, with most of its spikelets already fallen off. Still, important field marks could be noted, as shown at http://www.backyardnature.net/n/16/160724ss.jpg

First of all, the thousands of kinds of grasses can be divided into two big groups: those whose spikelets contain just one flower, or floret, and those with more than one. If you can't visualize the difference, check out our Grass Page at http://www.backyardnature.net/fl_grass.htm

In the above picture our roadside species is clearly of the one-floret kind, so it's definitely not a bluegrass, not a fescue, or any of the other big grass groups whose spikelets bear more than one floret. Another good field mark is that the flowering head, or inflorescence, is of the panicle type, with divisions branching more than once. Also, note that here and there florets appear to have fallen away leaving scale-like glumes on their little stalks, or pedicels. When the florets of many kinds of grass fall, the glumes go with them, so this is a good field mark.

Then I noticed that a little farther off the road the same species was growing much more lushly in its less deserty habitat, shown at http://www.backyardnature.net/n/16/160724sq.jpg

That plant had florets still issuing pinkish, pollen-filled anthers and white, much branching styles, shown at http://www.backyardnature.net/n/16/160724sr.jpg

One last feature to check before trying to ID the grass was the ligule, the rim-like structure at the blade's base where it meets the stem. Some grass kinds have ligules, some don't, and when they're present they come in a wonderfully diagnostic variety of forms. In the literature our grass's ligules are described as a fringe of hairs 0.2–0.3 mm long, which is what we see at http://www.backyardnature.net/n/16/160724st.jpg

Our roadside grass belongs to a large, well-known group called dropseeds, the genus Sporobolus. Several Sporobolus species are listed for the Yucatan, but the above field marks -- especially the panicle's narrowness and the short, hairy ligule -- leads us to SPOROBOLUS JACQUEMONTII, graced with a number of English names, including American Ratstail Grass, Giant Smutgrass, Smutgrass, West Indian Dropseed, West Indian Rrush-grass, West Indies Smutgrass, and more.

It's native to most of tropical America and has become an invasive weed in much of the rest of the tropics. In Queensland, Australia it's listed as a Class 2 environmental weed, meaning that landowners must take all reasonable steps to keep land free of the species, and that it's illegal to sell it or its seeds.

Here Sporobolus jacquemontii is well behaved, not seeming aggressive at all, just occupying environments too harsh and sterile for other plants to root in. It's a good citizen doing its job to stabilize the soil and keep down erosion.

*****

FLOWERING HELICONIA
Back in December, 2009, here at the Hacienda, we looked at fruiting heliconias, Heliconia latispatha, sometimes called wild plantains. You can see what they looked like then in fruit at http://www.backyardnature.net/yucatan/heliconi.htm

Nowadays they're flowering. You can see some plants next to the hut about eight feet tall (2.5m) in full bloom at http://www.backyardnature.net/n/16/160724hc.jpg

The large orange items in that picture are modified leaves, or bracts, that attract pollinators. You can see that the bract at the bottom right is half orange thing, half leaf. A close-up of a regular orange bract is at http://www.backyardnature.net/n/16/160724hd.jpg

In that picture, the actual flowers are the green items peeking up from the trough of the scoop-shaped bract. Note the pale tip of one of the flowers. Those are stamens projecting from the green flower's mouth. A close-up look into the bract's trough is at http://www.backyardnature.net/n/16/160724he.jpg

The picture shows the stamens poking from the green flower. The pea-like items in the trough to the left of the flower are ovaries from which the male parts, calyx and corolla have fallen, leaving dark scars atop the ovaries. The ovaries will mature into fruits like those we photographed in 2009.

*****

RALFS AT MIDDAY
The other day around noon I took a picture of my Latvian friend Ralfs because he was doing something utterly impossible to accomplish in North America and Europe. See if you can figure out his feat at http://www.backyardnature.net/n/16/160724rf.jpg

What Ralfs is doing is casting a shadow that hardly extends from right beneath him. North Americans and Europeans can't do that because those continents are north of the Tropic of Cancer, so the Sun never shines directly overhead there, and thus can never cast a shadow directly beneath anything it shines on. Here we're south of the Tropic of Cancer, so for a time each year the midday Sun is north of us, while the rest of the year it's to the south. Twice a year, when its daily path either approaches the Tropic of Cancer or starts leaving it, it passes directly overhead here. Around this time of year, at midday, at a certain moment, it's nearly exactly overhead.

On the Internet you can learn how near shining directly overhead the Sun can get in your area. The US Navy provides a page for helping you at http://aa.usno.navy.mil/data/docs/AltAz.php

There you need to plug in either the name of your US city or else provide coordinates of latitude and longitude for your location elsewhere on Earth. Down the page, there's a link where you can find your own latitude and longitude.

Plugging in Chichén Itzá's coordinates of W 88° 44', N20° 42' I find that for the date July 22, 2016 the Sun during its journey from east to west is closest to exactly overhead between 12:00 and 12:10 CST -- 89.8° at 12:00 and 90.7° ten minutes later. When it's at 90° it's at the highest point of journey from horizon to horizon -- its azimuth -- but it was not necessarily directly overhead. On July 22, the point at which it was closest to directly overhead, independent of whether it was at the highest point of its azimuth, was at 1PM, when it stood at 89.3° from the horizon. That number is referred to as its altitude, and 90° would be exactly overhead. The two points don't coincide in time because the Earth is tilted on its axis as it orbits the Sun.

Our 89.3° means that on July 22 the Sun wasn't exactly overhead, but pretty close. During the Summer Solstice, here at midday the Sun would be lower than it is now, a bit to our North, because we're south of the Tropic of Cancer, which is where, on the Solstice, the Sun would be directly overhead. Here the Sun is most overhead twice a year, as its journey takes it to and from the Northern Hemipshere's Tropic of Cancer.

If you do these figures for your location anyplace else than between the Tropics of Capricorn and Cancer, you'll find that your numbers simply never approach 90°, and in Ralfs' Latvia so close to the Arctic, the numbers are far from 90°, and people's shadows always are much, much longer.

*****

WHITE CLOUD, BLUE SKY, WHITE BUTTERFLY
Because I took the time to look into the sky, I saw something interesting.

A white butterfly, high above and driven by winds that near the ground didn't stir, was blown in a straight line across my field of vision. The white butterfly stood out against the blue sky, but against the white cloud made only a dingy speck. Against the white cloud the speck was dark because the cloud not only was white, but also glowed as clouds do when they're small enough for sunlight to diffuse through them, illuminating every water droplet inside them, each droplet broadcasting its rainbow hues to its neighbors. In contrast, with the butterfly against the blue sky, its wings showed only their shadowed underside, while during upbeats, with the wings folded above, for an instant I saw nothing of it at all.

All this was easy to figure out, but the white butterfly's passage still left an impression.

For, isn't life just like life? That which drifts along effortlessly glowing with its own internal light outshines whatever hustles just to keep aloft. That's what the Buddha tells us, and to a certain extent Jesus and some of the rest.

So, what is the essential difference between a cloud and a butterfly?

Maybe the Buddha would say that the radiant cloud seeks no identity, assumes whatever shape the air gives it, and admits into itself whatever comes its way. The butterfly, however, after having lived a long time as a caterpillar obsessively chewing leaves in order to grow, then resting briefly as a chrysalis, now has emerged as a winged adult working hard to find a mate and produce offspring. Remember the female Variegated Fritillary we saw recently mating while she was still on the chrysalis exuvia she'd just emerged from.

Butterflies are poems of hunger and desire.

But, if the butterfly's way of being is preached by the Nature Bible, isn't that teaching just the opposite of what the Buddha and Jesus seem to say?

Moreover, as an old graybeard sitting looking into the sky, my own life experience reminds me that when I was a butterfly driven by winds that didn't stir close to Earth, then I would have told you that any other way of being than being like a hungry, lusty butterfly would have killed me with its desperate dreamlessness, lonliness, and untouchability.

But, maybe Nature's teaching is more nuanced than suggesting one way over another. After all, the light we're talking about ricocheting into our eyes from cloud, butterfly and sky, science tells us, itself manifests two natures. On the one hand, light behavea like tiny sandgrains traveling through space but, on the other hand, also it behaves like electromagnetic radio waves.

Could not light's teaching be that white cloud, blue sky and white butterfly all are all perfect in their own ways, doing what is perfect for them as they are what they are? The light is the thing that teaches, not the cloud, sky and butterfly, and light has two natures.

What a thing this world is, with its blue skies, white clouds, white butterflies, and whole theaters of illusions to touch, smell, hear, taste, see and think about.

*****

Best wishes to all Newsletter readers,

Jim

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