August 3, 2014

EASTERN PONDHAWK
A large, unusually thick-bodied, very blue dragonfly landed on a concrete culvert projecting into one of the ponds at Cook's Slough Nature Park on Uvalde's south side. You can see it at https://www.backyardnature.net/n/14/140803ph.jpg.

Using Sidney Dunkle's Dragonflies through Binocularsit was easy enough to figure out that this was one of several species known as pondhawks, but there were two deep-blue pondhawk species with especially thick abdomens -- the Eastern and Western Pondhawks. In both species the males are blue while females are green. Pictures seem to show that our Uvalde pondhawk is dark blue like the Western species, while Dunkle's distribution map indicates that in our area we have the Eastern species, not the Western.

However, the species descriptions said that the cerci of Eastern Pondhawks are white while those of the Western species has black ones. Cerci are the two tiny, claw-like items visible at the very tip of the abdomen, in our picture clearly visible in the lower, right corner. Those cerci look more gray than white, but at least they're not black, so that agrees withs the distribution map, making this the Eastern species. Therefore: Eastern Pondhawk, ERYTHEMIS SIMPLICICOLLIS.

Eastern Pondhawks occur throughout the eastern US and contiguous Canada, west to Nebraska and Arizona, plus the Caribbean, and south throughout Mexico to Costa Rica in Central America. It's common over most of its distribution and is considered to favor human-modified wetlands, which is exactly what the ponds are at Cook's Slough. This predisposition has enabled Eastern Pondhawks to become one of the most abundant species in the eastern US.

Pondhawks in general (genus Erythemis) are thought of as voracious and aggressive, sometimes taking prey as large as themselves, which they hold on to with three large spines on each middle and hind thigh. In our picture, remembering that the thigh is the upper, thicker part of the leg, you can see these three spines.

Among the pondhawks, of which five species occur in North America, the Eastern species is considered especially ferocious, attacking even each other. They remove great numbers of flying insects, including those thought of as agricultural pests. The male's vigorously defended territory consists of about five square yards (meters) of floating vegetation such as algae and duckweeds. Ours was patrolling a band of duckweed gathered up against the pond's bank.

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PAPER WASP STARTING OVER
A couple of weeks ago we looked at a colony of paper wasps beneath the roof of a shelter at Cook's Slough Nature Park on the south side of Uvalde. You can see the healthy colony of worker sisters toilng diligently on the paper nest, with eggs and grubs visible in the cells, at https://www.backyardnature.net/n/a/polistes.htm.

Somebody knocked the nest down, and now where the larger nest had hung there's a much smaller nest with one wasp working on it, presumably the queen. Eggs are visible in the cells. You can see this at https://www.backyardnature.net/n/14/140803po.jpg.

Is this the same queen who lost the previous nest? Whatever the case, I feel sorry about the whole thing.

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SCARLET SAGE
Down in Uvalde on the Coastal Plain 35 miles south of Juniper House the landscape is much greener than here, and wildflowers are much more in evidence. I'm told that in years past normally it was the opposite, as evidenced by our having forests of juniper and oak on our hills here, but only low scrub of Mesquite, various acacias and such down there. You can see one pretty cluster of wildflowers just outside Uvalde, next to a fence where the mowers couldn't get them, at https://www.backyardnature.net/n/14/140803sv.jpg.

A close-up of the brilliantly red, inch-long (25mm) flowers is at https://www.backyardnature.net/n/14/140803sw.jpg.

The plant's leaves, two to a node and therefore "opposite," on a stem that's square in cross-section, are shown at https://www.backyardnature.net/n/14/140803sx.jpg.

The strongly bilaterally symmetrical flowers, opposite leaves and squared stem suggest the Mint Family, but gardeners hardly need to think in taxonomic terms to know that here we have the famous Scarlet Sage, SALVIA COCCINEA. Our plants may look different from Scarlet Sage in your garden because most garden cultivars are selected to be shorter and to have more numerous, more closely packed and longer lasting flowers than the wild plants, and these outside Uvalde are wild.

We often encountered Scarlet Sage in Mexico. Our page on the Mexican plants, with a picture of a cut-open blossom showing how the stamens' filaments have been modified to form a remarkable mechanism for daubing pollen onto the beaks of hummingbirds looking for nectar is at https://www.backyardnature.net/mexnat/scarlet.htm.

Wild Scarlet Sage occurs far beyond its presumed native land of Mexico. It ranges from the US Southeast where it's especially at home on hot sand along the Gulf Coast, south through all of Mexico and Central America into South America as far as Brazil.

Among folks using medicinal herbs, sages in general are thought of as affecting the nervous system, the most typical effect being a general mellowing out. One web page describes a more precise effect: "... calming without distancing ourselves from the issues at hand, simply soothing us enough to look life in the face." Among the many sages, genus Salvia, Scarlet Sage is singled out as "quite relaxing." You can make teas from the leaves, alcohol-based tinctures, extracts with vinegar and oils, and some people just eat the leaves, though at least one report mentions leaf-eating as causing headaches.

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SMALLHEAD SNEEZEWEED
At Cook's Slough Nature Park on Uvalde's south side, some of the low levees separating water treatment ponds are fairly overgrown with the dense, much-branched, knee-high, weedy member of the Composite or Sunflower Family shown at https://www.backyardnature.net/n/14/140803he.jpg.

Nowadays we're at the end of this species' peak flowering period, and most plants, which are annuals, are drying out crisp and brown. In the above picture a green plant still bearing flowers occupies the foreground while in the background you see plants in the dried-out, apparently dead state more typical at this time. At first glance the plants couldn't look more scrappy and disreputable, but up close you start seeing interesting details, as shown at https://www.backyardnature.net/n/14/140803hf.jpg.

Among those flowering heads we see a green head with its disc and ray flowers not yet expanded, some older heads on which the fruits are developing, and some heads in full flower, though the "rays" below the spherical part are much tinier than in "normal" composite, daisy-type flowers. On all the heads it's the spherical part that strikes us a most unusual. A close-up of a single head enabling us to see better what's going on is at https://www.backyardnature.net/n/14/140803hg.jpg.

At the head's bottom, those slender, curved, green things are the bracts or scales forming the involucre, individually known as phyllaries. This species' phyllaries are unusual because they're so slender and projected downward. In most composite flowering heads phyllaries are somewhat triangular , directed upward, and overlap one another like shingles on a roof as they form a kind of green bowl for the flowers. The yellow, petal-like ray flowers are very unusual because their yellow blades are so short and inconspicuous. The spherical part, which is distinctive just because it's spherical and not flat or convex, consists of closely packed disc flowers affixed to a spherical, vegetative platform known as the receptacle. You can see the receptacle of a head from which part of the disk flowers' mature, cypsela-type fruits have been removed at https://www.backyardnature.net/n/14/140803hh.jpg.

The plant's leaves also do something interesting: Their margins, instead of narrowing to a petiole, often flow onto the stem itself, forming green, narrow "wings" along the stem below the leaf. A closer look at a leaf and the plant's "winged stems" is at https://www.backyardnature.net/n/14/140803hi.jpg.

Earlier we've profiled plants displaying this exact combination of anatomical features, though at first glance the plants looked very different. Back East a common weed along dry, sandy roadsides with these features is the Bitter Sneezeweed, shown on our page at https://www.backyardnature.net/n/h/sneeze.htm.

Another plant with the same basic features, though looking very different, is the local Pretty Sneezeweed shown at https://www.backyardnature.net/n/h/helenium.htm.

Both of these sneezeweeds belong to the genus Helenium, so the moment this Uvalde plant revealed its flower structure, it was pretty clear that it was yet another Helenium. That's not surprising, since seven sneezeweed species are listed for Texas.

With its exceedingly small heads, our Uvalde plants are appropriately named Smallhead Sneezeweeds, HELENIUM MICROCEPHALUM, with that microcephalum in the binomial meaning "small head." In the US Smallhead Sneezeweeds occur from Arizona to Oklahoma south into northern Mexico.

Small, seed-eating birds such as finches can easily be imagined perching on the plants' stiff stems as they feed on tiny, dry fruits, but Smallhead Sneezeweeds are otherwise famous in these parts as being highly toxic for grazing livestock. A webpage of the Uvalde Research and Extension Center, associated with the Texas A&M University System, reports that Smallhead Sneezeweed is extremely poisonous to livestock, even mules and goats, causing 'spewing sickness," the symptoms of which are "... weakness and staggering, diarrhea, vomiting green material, green salivation or discharge from nose, bloating, gastroenteritis and death."

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SWAMP SMARTWEED
Smartweeds produce fingerlike flowerheads composed of many tiny, normally closely clustered flowers, which often are pink or white. Many species exist and some are weedy, so it's a good group of plants to know just because you run into them all the time. They're members of the Buckwheat Family, the Polygonaceae. The other day at the sometimes submerged edge of a little ephemeral stream in Cook's Slough Nature Park on Uvalde's south side a smartweed turned up, shown at https://www.backyardnature.net/n/14/140803pg.jpg.

Notice how the stems tend to recline. A close-up of some flowers is at https://www.backyardnature.net/n/14/140803pf.jpg.

That picture shows an important feature of members of the Buckwheat Family: Instead of the flower having a green calyx below a colorful corolla, there's just one thing like a merged calyx and corolla. In such cases we call the whole structure the perianth, and instead of referring to calyx sepals or corolla petals, "tepals" are spoken of.

Maybe the best field mark of all for the Buckwheat Family, however, is what's shown at https://www.backyardnature.net/n/14/140803pe.jpg.

Notice that where each leaf attaches to the stem, immediately above the connection point a cylindrical membrane surrounds the stem. You can think of that as stipules grown together, stipules being tiny, leaf-like things often at the base of leaves. When stipules grow together into a cylinder around the stem we often say they form a "stipular sheath," but the structure's fancy name is "ocrea." If you find a plant with ocreae, that's a very good sign that you have a member of the Buckwheat Family, though not all genera in the family produce them.

We've seen our Cook's Slough species nearly everyplace we've visited the last few years, but it still always gives a little trouble when I want to be sure it's really what I think it is, and not something closely related. Some very similar species exist, and this one is remarkably variable. It's so variable that throughout its taxonomic history it's been assigned quite a few names by botanists who were certain they'd found a new species, but which turned out just to be a normal variation of this one.

Our plant is the Swamp Smartweed, POLYGONUM HYDROPIPEROIDES, or Persicaria hydropiperoides according to some specialists. You see the two names used about equally. I stick to Polygonum because that's how I learned it.

So, in the field, if you're where the soil at least sometimes is waterlogged or even submerged and you see a smartweed halfway reclining on the ground, its flowering heads are slender, white, and the flowers aren't as closely packed together as in most smartweed species, the flowers' five tepals are not particularly dotted with glands, and the ocreae bear along their top margins hairlike "bristles" up to 10mm long (3/8ths inch), then probably you have our Swamp Smartweed. The tepals numbering five and the longer-than-typical bristles atop the ocreae are especially good field marks.

Swamp Smartweed occurs all across the US and contiguous Canada, except in some high, arid western states, as well as all through Mexico and Central America into South America. Sometimes it forms masses along lake shores, as shown in a picture we took back in Mississippi still online at https://www.backyardnature.net/n/12/120701pg.jpg.

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ROSANNA FREYRE'S SEEDS
Last September we looked at an uncommon wildflower occurring in cobblestone fields along the Dry Frio River. It was the Mexican Petunia profiled at https://www.backyardnature.net/n/h/ruellia4.htm.

A few months after that page was published, Dr. Rosanna Freyre, a research scientist in environmental horticulture at the University of Florida, wrote, asking for seeds. You can meet Dr. Freyre at http://hort.ufl.edu/people/freyre.shtml.

Dr. Freyre wrote during the winter when no seeds were available, so I told her to remind me in a few months. She did, and this week after searching most of a morning I found one plant flowering, shown at https://www.backyardnature.net/n/14/140803ru.jpg.

The plant bore both flowers and fruits, shown at https://www.backyardnature.net/n/14/140803rv.jpg.

A blackish fruit nestled within dry, brown sepals is shown at https://www.backyardnature.net/n/14/140803rw.jpg.

This plant was growing well, bore green leaves and lots of flowers and fruits, much in contrast with other wildflowers here, because of the serious drought. I think the reason this plant looked so good was that it was a woody perennial, probably with deep roots. The woody base is shown at https://www.backyardnature.net/n/14/140803rx.jpg.

I sent lots of fruits to Dr. Freyre, and I took all these pictures because maybe it'll turn out that our plant will make a good garden plant, or at least contribute some genes to another wild petunia species with bigger flowers, but weak roots.

Whatever the case, I'm always tickled to help researchers like this, and I hope our seeds produce many pretty Mexican Petunias.

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MILO
On the bench below the birdfeeder on Juniper House's deck I keep several pots of herbs, and a big pot of Aloe vera. I like having Aloe vera around not only so I'll have the succulent leaves handy so I can daub their gummy juice onto burns and other skin irritations, but also I make a pleasant tea from the gel inside the leaves. Well, a seed from the birdfeeder must have fallen into the Aloe vera's pot, for a grass grew up there and since it didn't look like a weed grass, I let it flower. You can see the grass in its pot at https://www.backyardnature.net/n/14/140803sg.jpg.

The grass's flowers where sexually active a couple of weeks ago when pollen was being released from pale yellow anthers dangling from threadlike filaments, as seen in a picture of the flowering head at https://www.backyardnature.net/n/14/140803sh.jpg.

In that picture notice that the individual spikelets are on short stems, or pedicels, which arise from branches off the main flowering stem, or rachis. In other words, this flowering-head is a panicle-type inflorescence, something to keep in mind during the identification process. You can see individual spikelets, some of their florets issuing fuzzy stigmas for collecting pollen, and other spikelets whose florets have dangling, banana-like anthers with open pores at their bottoms where pollen dribbles out, at https://www.backyardnature.net/n/14/140803si.jpg.

Seeing the very plump spikelets held in a panicle, already I suspected the grass's identity this was, but just to be thorough in gathering information for IDing, I photographed the ligule, the obscure, wall-like growth at a grass blade's bottom where it meets the stem. Ligules look the same throughout a species, but vary drastically between genera and species, and sometimes don't exist at all. You can see that this grass's ligules consist of a low, green, membranous wall topped with tiny, white hairs, or cilia, at https://www.backyardnature.net/n/14/140803sj.jpg.

This week, after two weeks of growth, the caryopsis-type grains, or fruits, have enlarged much, much more than "normal" grass grains might, becoming more or less spherical and actually swelling well beyond the scales, or glumes, lemma and pellea, that enclose the mature grains of normal florets. You can see this at https://www.backyardnature.net/n/14/140803sk.jpg.

Not only does that picture show us the oversized grains, but also now that the individual florets are pushed apart by their big grains impinging on one another, it can be see that next to every hairy spikelet producing a big grain there are smaller, slenderer, less hairy spikelets. The big, hairy ones are fertile spikelets while the smaller, less hairy ones either are male or completely sterile. You might also make out that the large, fertile ones don't have a stem beneath them, while the smaller, infertile ones do. This manner of having its inflorescence composed of pairs of spikelets, with one of the pair being large, fertile, stemless and the other smaller, infertile and short-stemmed, is an important feature of this grass.

So, this is SORGHUM BICOLOR, one of the world's most important domesticated plants, being the fifth-most consumed of all grasses, only being eaten less than corn (maize), rice, wheat and barley. Over the centuries humans have developed many cultivars from the species, and today these cultivars are thought of as clustering into four major groups:

Our Sorgum bicolor, because of its large grains, is of the Milo type -- sometimes referred to as grain sorghum. That sounds right because the bag my birdseed came in says it contains "White Millet, Milo, Wheat, Cracked Corn, Black Oil Sunflower." Millet grains are smaller -- "canary seeds."

Though many researchers have tried to figure out the horticultural history of Sorgum bicolor, its history is still not clear. It appears to be native to Africa, especially Ethiopia, but its domestication either could have begun there, or the wild grain could have been carried to India where it was domesticated, then returned to Africa, where it was further developed. It's believed that African slaves brought sorghum seeds with them to the US, and now the US is the top sorghum growing country in the world.

My guess is that during upcoming years Milo will become even more important in the US as a cereal crop, because as global warming brings less rain to traditional corn (maize)-growing states, those states will shift to Milo because it needs much less watering. Also, Corn is cross-pollinated, so that if rain fails during silking time, barren ears (no kernels) may develop. But Milo is self-pollinated and produces heads over a longer time, so several weeks of severe drought affect Milo much less. In long droughts, Milo may produce fewer and smaller heads, but at least they produce something, when corn may produce nothing.

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FEATURED ESSAYS FROM THE PAST:

"Barklice and Worldcom" from the June 30, 2002 Newsletter, at https://www.backyardnature.net/n/p/020630.htm

"Human Evolution Needed Boneheads" from the June 30, 2008 Newsletter, at https://www.backyardnature.net/n/p/080630.htm

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Best wishes to all Newsletter readers,

Jim

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