August 31, 2014
LOUNGING EGRETS
There's an end-of-summer feeling in the air, even here in southwestern Texas. In mid-afternoon the temperature can still reach 100° or more (38C) but it feels drier than during recent weeks, and if you keep quiet in the shade, it's pleasant enough.
For these last few months birds have been busy raising families, but now you see them slacking off, seeming more philosophical about things. Atop a Netleaf Hackberry tree on an island in one of several ponds in Cooks Slough Nature Park on Uvalde's south side, it was gratifying to see several white egrets or herons preening and gawking around. I didn't know which species they were until their picture appeared later on my laptop screen, and then it was clear that with such thick necks and blushes of rustiness on the napes and breasts of older birds, they were Cattle Egrets, as you can confirm at https://www.backyardnature.net/n/14/140831eg.jpg.
That silhouette in the background looks like it belongs to a Pterodactyl, but more likely it's a kingfisher.
Some of the Cattle Egrets in the picture are pure white, and these must be the young ones. In the picture, most adults with patches of rustiness are spaced out and busy preening, but the juveniles huddle together craning their necks looking around. There atop the hackberry tree on this hot morning when hectic road traffic rumbled across fields from a mile away and a police or Border Patrol helicopter circled the area these innocent, honest gestures pleased me more than I can say.
Our Cattle Egret page with much more information on the species is at https://www.backyardnature.net/n/b/bubulcus.htm.
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WHISTLING DUCKS
Though last spring numerous ducks could be seen on the ponds at Cook's Slough Nature Park on Uvalde's south side, during the summer mostly they disappeared, but now they're drifting back again. This week, the most conspicuous are the Black-bellied Whistling-ducks, some of which are shown at https://www.backyardnature.net/n/14/140831wd.jpg.
These individuals look like freshly minted adults. Juveniles possess dark gray bills but these have the adults' orange ones, though not brightly so. Also these birds' breasts are rusty brown like the adults', not grayish like juveniles', but the rustiness isn't as vibrant as on a fully mature adult.
Mostly this flock paddled around the pond's surface always keeping an eye on me, though I was a good distance away. If the main flock went behind the island, one bird always remained in the center of an opening where he could see me, never leaving his post. Whistling ducks strike me as particularly smart and wary, which -- along with global warming -- may account for the rapid expansion of the birds' distribution area northward.
Several times I witnessed seemingly spontaneous outbreaks of frenetic splashing and calling, lasting for just a few seconds. The sounds made were less whistles than squeals -- strange sounds for ducks to be making. They seemed to enjoy these occasional eruptions of apparent craziness, and I did, too.
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A FRESHLY EMERGED BORDERED PATCH
Arriving to continue painting a house in the valley, something dark was hanging on the white wall I'd painted only about two weeks earlier, so I went to check it out. It was a butterfly emerging from its chrysalis shell. In fact, its emergence was so far advanced that by the time my camera was out and focused, the butterfly was able to drop onto the concrete walkway below. You can see the split-open, empty chrysalis case sticking to the wall at https://www.backyardnature.net/n/14/140831bg.jpg.
It was a breezy morning and down on the concrete the freshly emerged butterfly was having a hard time. Its wings were so soft and pliable that the wind knocked them one way and then another, like moist cellophane. The butterfly frantically walked around in all directions as the limp wings flapped about and were dragged behind sliding on the concrete. I figured a plant was being sought to climb so he could hang upside-down with the wings dangling below as they slowly hardened. I picked up the little critter, nudged him onto a nearby Cowpen Daisy, and immediately he positioned himself beneath a flower and quieted down, the wings hanging downward, as shown at https://www.backyardnature.net/n/14/140831bf.jpg.
Even in that picture you can see that the wingtips at the very bottom are crooked and not fully deployed. Still, when I came back about half an hour later, there was no butterfly, so maybe the wings stiffened quickly, and the little being fluttered away.
Volunteer identifier Bea in Ontario tells me that this the Bordered Patch, CHLOSYNE LACINIA, shown from above with the wings open at https://www.backyardnature.net/n/a/uvalde/005.jpg.
Bordered Patches are mostly a tropical species, occurring from Argentina north through Central America and Mexico to as far as southern California to here, though irregularly they migrate as far north as Colorado and western Missouri.
Caterpillars of the Bordered Patch feed on leaves of members of the Composite or Daisy Family, to which the big colony of Cowpen Daisies right next to the chrysalis belong.
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WATER-HYSSOP
Cook's Slough Nature Park on Uvalde's south side is built around a series of interconnected artificial holding ponds filled with treated sewage water from Uvalde. The ponds purify the water enough to be released into the environment, and the ponds themselves attract plants and animals otherwise not to be seen in the dry scrub surrounding the park. On a low levee between ponds, around a concrete culvert conducting water between ponds, a much branching, sprawling herb formed a lush, green, carpet at the water's edge, as shown at https://www.backyardnature.net/n/14/140831bc.jpg.
At the picture's lower, right corner, sprigs of the plant on dry land bear tiny, white blossoms, while at the picture's left flowerless stems emerge from below the water, rising into the air. A flowering sprig from shallow water at the water's edge appears at https://www.backyardnature.net/n/14/140831bd.jpg.
Here you see that the plant's leaves are opposite (two leaves per stem node), that thick roots develop at stem nodes, and that the flower also arises at a stem node. Many plant species never root at their nodes, and many produce their flower clusters at stem tips. Also, notice that the flower's green, cup-like calyx with five sepals is subtended by two green, scale-like bracts, or "bracteoles." A peep into the flower's mouth is afforded at https://www.backyardnature.net/n/14/140831be.jpg.
In this picture two features helping in this plant's identification are that the stamens are "didynamous," and the stigma is "capitate." Didynamous stamens are those occurring four per flower, in two pairs of different lengths. The word "capitate" means "formed like a head," as opposed to being sharp-pointed, flat, or some other shape, so that fits our capitate stigma, which is the green, rounded-topped item atop the style issuing from the flower's center.
If we had fruits, we'd see that they are dry capsules that split open to release many small seeds, and such fruits associated with such plants bearing such flowers suggest the Figwort or Snapdragon Family, the Scrophulariaceae.
With our little mat-forming herb having opposite, unlobed leaves, five sepals not four, and corolla lobes or petals much longer than the cylindrical part of the corolla below them, the plant keys out to the genus Bacopa, species of which often are referred to as water-hyssops. Two water-hyssop species are listed for area.
In southwestern Texas, to know which water-hyssop species we have, it's enough to see that the leaves have only one vein down their middles, not several radiating from the blade bases. This is what's often called Coastal Water-hyssop, and sometimes Herb-of-grace -- BACOPA MONNIERI. Coastal Water-hyssop occurs worldwide in tropical and otherwise warm places. In the US it thrives in watery habitats throughout the southern coastal states. Over its huge area of distribution its corolla color can range from white to purple and blue.
If you look up Bacopa monnieri on the Internet you'll find plenty of pages about it, but most won't call the plant Coastal Water-hyssop. The main name used in cyberspace is "Brahmi," and those pages extol the plant's fame in the service of Ayurvedic medicine, where it is noted as "... an effective and powerful herb helpful for memory and combating stress." One website sells a plastic bottle of 180 capsules containing Brahmi for $37.20.
Bacopa monnieri's Wikipedia page has sections on its biology, traditional uses, pharmacology and toxicology at http://en.wikipedia.org/wiki/Bacopa_monnieri.
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GIANT RAGWEED
Nowadays one of the first things my neighbor Phred does when he steps outside his air-conditioned house is to go through a fit of sneezing. One reason for that might be shown at https://www.backyardnature.net/n/14/140831am.jpg.
That's Giant Ragweed, AMBROSIA TRIFIDA, which most of us have seen in weedy spots, especially moist ones. I hadn't expected it here because of the aridness, but you can see that the seven-ft-tall one (2m) in the picture stands next to a prickly pear cactus. Actually, Giant Ragweed is quite common in Cook's Slough Nature Park on Uvalde's south side, especially in shade and next to ponds. In the Dry Frio River Valley 35 miles to the north, on the Edwards Plateau southern slope, I've not seen one.
Though 22 ragweed species -- members of the genus Ambrosia -- are listed for North America, Giant Ragweed is easy to distinguish from all the others not only by its size but also for its large leaves which normally are deeply lobed with up to five "fingers," as shown at https://www.backyardnature.net/n/14/140831an.jpg.
At WebMD.com one reads that "... most cases of hay fever are caused by an allergy to fall pollen from plants belonging to the genus Ambrosia -- more commonly known as ragweed." And Giant Ragweed produces prodigious amounts of pollen. The plant in the picture was topped with dozens of slender, pagoda-like, pollen-producing flowering heads, or racemes, as seen at https://www.backyardnature.net/n/14/140831ao.jpg.
Since ragweeds are members of the giant Composite or Daisy Family, each of those objects on a slender pedicel arising from the racemes' stems is a cluster of tiny male flowers. You can see some tiny heads of male flowers at https://www.backyardnature.net/n/14/140831ap.jpg.
Each little head is structurally like a daisy, in that each consists of a green, bowl-like "involucre" (held upside-down in ragweed racemes), inside which reside several individual male flowers, or florets. In our picture, most florets inside their involucres haven't opened yet to release pollen, but some have. All the florets in each involucre consist of nothing but stamens. Each pollen sac in every anther of every male flower contains thousand of pollen grains. It seems that Giant Ragweed produces much more wind-dispersed pollen than it can possibly need. I read that a single plant can produce 10 million pollen grains daily and more than a billion pollen grains during its life cycle.
So, where are the female flowers? If you look for them you can find them at the racemes' very bottoms, as seen at https://www.backyardnature.net/n/14/140831aq.jpg.
In the picture's top you see two nodding involucres bearing male flowers, but in the picture's lower half those blackish, eggfruit-like items topped with V-shaped stigmas are female flowers. The eggfruit-like things will mature into cypsela-type fruits -- dry, one-seeded fruits that don't split open at maturity. In the old days, ragweeds were thought to pollinate themselves, but now it's known that they're strongly self-incompatable. A plant's pollen may generously douse its own female flowers, but the male and female sex germs at the genetic level just can't get it together.
Unlike most weeds, ragweeds are native Americans, though they've become weedy in other countries. Giant Ragweed ranges all across southern Canada south through all of the US into northern Mexico, so the species' vitality and robustness must be admired.
Since Giant Ragweed is native, indigenous Americans had uses for it. The Cherokee used it medicinally for insect stings, hives, fever, and pneumonia, and the Iroquois used it to treat diarrhea. I read that it's been used successfully as a compost activator and as a cover in sheet mulch gardens. The stems are so thick and tough ,though, so a wood-chipping machine might be necessary for these latter purposes.
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TOOTHLEAF
In an arroyo bank's rocky soil in the upper Dry Frio floodplain where dog-days heat and the multi-year drought had stunned most wildflowers into crisp, brown submission, one tough, knee-high plant caught my attention not only with its bright greenness but also by its stems' unusual, branching-from-the-top form, shown at https://www.backyardnature.net/n/14/140831st.jpg.
There you can see last year's dead stems at the plant's base, so this is clearly a perennial. Up closer we see that at stem tops not only does multiple branching occur, but also where all the branches originate, there are immature, pea-sized fruits, as shown at https://www.backyardnature.net/n/14/140831su.jpg.
At the tip of some branches, spikes of much reduced male flowers may be accompanied at the spikes' bases by female flowers, as seen at https://www.backyardnature.net/n/14/140831sv.jpg.
In that picture notice that leaf margins bear many glandular "teeth." Also, beneath the green ovary or immature fruit at the image's lower, left, notice the yellowish, bowl-like, pollinator-attracting nectar gland. Moreover, if you look closely, you can see that each cluster of stamens on the spike also arises next to nectar glands, though smaller ones.
Notice that the fruits have three rounded corners. The vast majority of dicot fruits, if not round in cross section, are four or five angled, so this is a significant field mark. A shot of a mature fruit beginning to split open is at https://www.backyardnature.net/n/14/140831sw.jpg.
A broken-apart capsular fruit with one of its white seeds is shown at https://www.backyardnature.net/n/14/140831sx.jpg.
So, here we have a plant that produces three-cornered fruits, separate male and female flowers on the same plant, and it's very glandular. If you break a leaf of this plant, a milky latex exudes from the wound, too. In other words, of what family could this plant belong other than the big, mostly tropical Spurge or Euphorbia Family, the Euphorbiaceae? Even in the Temperate Zone, when you see three-sided fruits like that on a dicot, the first family to think of is the Spurge Family.
However, unlike last week's spurge species where male and female flowers crammed together in a tiny, cuplike cyathium, the flowers of this week's member of the family are much larger and separated from another, so our arroyo-bank plant isn't a spurge itself, but rather a member of a different genus in the Spurge Family.
Once we know we have a member of the Spurge Family, the main field marks directing us to the right genus include:
In Texas these traits suffice to distinguish our plant as a member of the genus Stillingia, in which about 30 species are recognized, all occurring in tropical and semitropical parts of the Americas, with a handful of species extending north into the US southern states. Species of Stillingia often are referred to as toothleafs because of the toothy glands along the leaves' margins. Three Stillingia species can be found in Texas, but only one of those produces such narrow leaves as are shown in our picture, and that's STILLINGIA TEXANA, variously known as Texas Toothleaf, Queen's Delight and Texas Queen's Delight. Texas Toothleaf occurs almost exclusively in Texas, though it's been found spottily in Oklahoma, New Mexico and across the river in Coahuila State, Mexico.
I can't find why toothleafs are so delightful to queens, but another name used for one or more Stillingia species is Cockup Hat, so to certain people there must be something particularly alluring about these plants.
Members of the Spurge family are famous for their juices containing toxic or medicinal compounds, depending on the dosage, and toothleafs have long been regarded both as potentially poisonous for grazing livestock, and as powerful medicinal herbs. The plants are so unpalatable that usually livestock won't eat them, except when food is hard to find. Then if the plant is eaten its cyanogenic glycosides might release free cyanide into an animal's rumen, and you know how deadly cyanide is.
The WbMD.Com website says that "Despite serious safety concerns, people take queen's delight to treat liver disease, gallbladder disorders, skin diseases, constipation, bronchitis, and hoarseness (laryngitis)." It's also been used to induce vomiting and as a “blood purifier.”
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HALL'S PANICUM
If you're looking for rare or unusual plants, one good strategy is to visit extreme habitats -- places uncommonly dry, wet, exposed to sun and wind, thin soil atop rocks, etc. Therefore, I wasn't surprised when in the very thin, rocky soil atop the hard layer of Edwards Limestone capping the hill on which Juniper House sits, a grass turned up I hadn't noticed on the slopes and in the Dry Frio Valley below. The foot-tall grass called attention to itself with its very curly, slender leaves, as seen at https://www.backyardnature.net/n/14/140831pm.jpg.
Its flower clusters, or inflorescences, consisted of small spikelets on short, slender stems, or pedicels, which arose from branches of branches off the infloresence's main stem, or rachis -- so that it was a panicle-type inflorescence -- as seen at https://www.backyardnature.net/n/14/140831pn.jpg.
Up closer you can better see the slender pedicels and the spikelets' conspicuously several-ribbed glumes at https://www.backyardnature.net/n/14/140831po.jpg.
The spikelets on our plant were maturing and falling off. You can see some at https://www.backyardnature.net/n/14/140831pq.jpg.
Some grass types drop naked caryopsis-type fruits (dry, one-seeded, not splitting at maturity) but you can see that in this species the caryopses fall mostly enclosed with scales, or glumes. Moreover, the typical grass spikelet consists of two conspicuous glumes, but these appear to bear three. From past experience with this genus, we know that the lower, shorter scale is actually what remains of a sterile, much-reduced second spikelet. Still, that "third glume" is an important field mark.
These traits -- the panicle-type inflorescence, the one-flowered spikelets and the spikelets appearing to be subtended by three instead of two glumes -- point us to the big grass genus Panicum. With about 450 species, of which many are widely spread and commonly occurring, Panicum is a genus worth knowing. Species of Panicum often are referred to as panic grasses.
A large portion of Panicum species produce two leaf-types. At those plants' bases there'll be rosettes of short, broad leaves, typically produced the previous season. The main stem will arise from this rosette bearing longer, more slender leaves, and a panicle of flowering spikelets. Our hilltop Panicum however, produces no rosettes and there's only one leaf type, so that helps a lot in its identification.
Also, many Panicums are annuals, but with such dense tufts of curling leaves, it's easy to see that this species is a perennial, which also narrows down the possibilities considerably.
However, when keying out this species, the clincher is what you see at https://www.backyardnature.net/n/14/140831pp.jpg.
The white fringe of hairs is the ligule, a feature that may or may not exist at the base of a grass's leaf where it meets with the stem. Ligules can be hairy like this one, membranous or stiffly papery, and they can be long or short, shredded, cut down the middle -- all kinds of ways. Panicums in general produce hairy ligules of this type, but the combination of a substantial ligule like this, with the rest of the leaf, including the cylindrical sheath below the ligule, being hairless, is noteworthy.
These and other features identify our grass as the Hall's Panicum, PANICUM HALLII, distributed in the US southwestern states from eastern Texas north to Colorado and southern Utah, west to Arizona, and most of arid northern Mexico.
Hall's Panicum is regarded as only a fair grass for grazing livestock, but lately science has paid attention to it because it is closely related to Switchgrass, Panicum virgatum, which shows possibilities for being grown in mass culture as a source of biofuels. Also, Hall's Panicum has genes easy to work with. One research paper praises Hall's Panicum as a good plant to work with because it "... has the advantages of a tractable diploid genome, a manageable stature, self-fertility, a short life-cycle, and genomic sequence resources from DOE JGI." The words "genomic sequence resources" refer to the fact that Hall's Panicum has had its entire genome sequenced.
Beyond all that, Hall's Panicum is a worthy species if only because it grows in very dry, high-carbonate soil, protecting what little soil is there, and, with its curly leaves, it's a species easy to recognize, once you've been introduced to it.
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WANT TO LIVE MY TEXAS LIFE?
Before long I'll be leaving Texas. If anyone out there wants to live in Juniper House where I've been residing, in exchange for doing daily odd jobs for the owner, drop me a line via the page at https://www.backyardnature.net/j/writejim.htm.
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FEATURED ESSAYS FROM THE PAST:
"Intelligence" from the May 19, 2008 Newsletter, at https://www.backyardnature.net/n/p/080519.htm
"On Being Turned On" from the February 9, 2003 Newsletter, at https://www.backyardnature.net/n/p/030209.htm
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Best wishes to all Newsletter readers,
Jim
All previous Newsletters are archived at https://www.backyardnature.net/n/.
