JIM CONRAD'S
NATURALIST NEWSLETTER
Issued from the valley of the Dry Frio River on the
southern slope of the Edwards Plateau, northern
Uvalde County, southwestern Texas, USA

October 5, 2014

PATCH-NOSED SNAKE
Biking down the community's little gravel road a snake only about eight inches long (21cm) turned up right in the road's middle, motionless except for his flicking tongue. You can see him at http://www.backyardnature.net/n/14/141005pn.jpg.

I was tickled to see this snake, especially because during all of this extremely dry summer I've not encountered a single one. This looked like a garter or ribbon snake, so probably it wasn't anything special, but still I wanted to get some close-ups of the head, since the configuration of scales on the head are among the most important field marks in snake identification. My first head-shot is shown at http://www.backyardnature.net/n/14/141005po.jpg.

That picture shows scale patterns on the head's top but not the important ones lining the upper and lower lips. Well, I've handled rattlesnakes and coral snakes so to get a better head picture I simply reached out to grab the little fellow right behind his head... but he was so fast -- or I was so slow -- that I got the body's middle instead. This clumsy capture enabled the critter to turn around and with teeth no more dangerous than spines on a bug's leg, he bit me! And even though the bite was completely painlessness, my innate "startle response" kicked in and before I'd even realized what had happened I'd slung that poor creature across the road, where he promptly zipped into a hole. No further head pictures.

Still, with the scales atop the head visible in the picture I already had, I figured I could at least confirm that it was an immature garter or ribbon snake. Back home with the head image on the computer screen I began comparing the scales with those atop the heads of garter and ribbon snakes featured on the Internet. Beginning with the big scales behind and above the eyes, every scale fit perfectly, and so did the smaller ones in the "nose-bridge" area. But then that last scale, the one bending down over the very front of the head -- the "rostral" scale -- turned out all wrong. Rostral scales on the heads of garter and ribbon snakes adjoin the scales behind them along a straight line. The top of our snake's down-curving rostral scale wedges like a sharp tooth between the two scales above it -- between the "internasal" scales. In snake identification, such a big difference in scale configuration is not to be ignored.

So, our snake's rostral scale sent me looking for other lined snakes found in our area, and there was one, a kind of snake I'd never heard of, a Patch-nose Snake, SALVADORA GRAHAMIAE. Moreover, the top of its tip-of-nose rostral scale is shaped just like ours. It curves down the front of the head forming a flattish "patch nose," making the snake's head look oddly blunt.

The HerpsofTexas.Org web page for the Patch-nose Snake says that it typically forages during the early morning hours for lizards and small mammals, though the species can be found hiding under boards, flat stones, and dead vegetation. In Texas the species occurs in our juniper-wooded Hill Country, the Chihuahuan Desert of Big Bend and the Trans-Pecos, then east through southern New Mexico and Arizona, and south into arid northeastern Mexico.

Apparently Patach-nose Snakes are fairly common. I've seen them here before but I thought they were Western Ribbonsnakes -- until I got a good view of that nose-tip rostral scale.

*****

A HUGE OX BEETLE GRUB
While moving a pile of Mesquite firewood, at the very bottom of the pile where the wood was decaying, crumbling and becoming part of the soil, two enormous grubs turned up. One is shown in my hand at http://www.backyardnature.net/n/14/141005gb.jpg.

The curled-up grub was about two inches across (5cm). If I'd straightened him out, surely he'd have extended to 4 inches (10cm). Afraid that unbending him might cause injury, I only made a half-hearted effort at it, but even that caused him to poop an incredible amount of wet, reddish wood fiber onto my hand, revealing that this grub was an important agent for converting decaying wood to an organic form more accessible for other organisms.

A view of the grub's head, showing jagged-edged mandibles that could pinch a little, but not enough to hurt, is shown at http://www.backyardnature.net/n/14/141005gc.jpg.

A view better showing the grub's unusually scalloped side-flesh, with amber-colored spots surrounding the breathing holes, or spiracles, along its sides, and a characteristic amber blotch on the white skin just behind the head is at http://www.backyardnature.net/n/14/141005gd.jpg.

Volunteer identifier Bea in Ontario has been extra busy with her real work this week so I made a stab at identifying the grub myself. Lacking Bea's insights into the many beetle families -- and grubs like this are produced by beetles -- I sort of "cheated" with the very non-technical-but-sometimes-effective approach of doing a Google image search on the keywords "grub huge wood," and by golly the first thumbnail on the page that resulted illustrated a grub just like ours.

That picture was on Texas bug-maven "Valerie's" AustinBug.Com website, dedicated to bugs of the Austin, Texas area, and the grub was identified as an Ox Beetle, sometimes also called Elephant Beetle or Eastern Hercules Beetle; it's STRATEGUS ALOEUS. Valerie writes that "We find these huge creatures in the lower parts of our compost bins, where they feed on decaying wood." She also says that the grubs take at least two years to mature, "as wood is not a particularly nutritious diet."

The adult Ox Beetles into which these grubs metamorphose are regarded as the largest beetle species in the US, reaching about 2½ inches long (63mm). They're very closely related to Rhinoceros Beetles, the major form of the male adult possessing a long, slender "horn" between and just below an additional two long, wedge-shaped projections.

Ox Beetles range across the US southernmost states from Florida to Arizona. Mostly they're tropical insects, though, since from the southern US their distribution continues on south through all of Mexico, the Caribbean area and Central America, into South America, down to Brazil.

In fact, when I began looking for other pictures of Ox Beetle grubs, one of the first to turn up was one my own! In 2010 we profiled this same species at Hacienda Chichen in the central Yucatan. It had never occurred to me that the same species might occur here. You can see our Yucatan picture at http://www.backyardnature.net/n/10/101205ox.jpg.

*****

BURR OAK
One of the most distinctive, robust and best known of all oaks, one with characteristically deeply lobed leaves and enormous acorns with fringed, scaled cups, is shown at http://www.backyardnature.net/n/14/141005ok.jpg.

That's the Burr Oak, QUERCUS MACROCARPA, the "macrocarpa" in the binomial meaning "big fruit." And that acorn-type fruit really is large, as shown with my hand serving as scale at http://www.backyardnature.net/n/14/141005ol.jpg.

Burr Oak acorns are the largest of all oak species -- with cups up to 2-3/8ths inch across (60 mm). The species is distributed from southern Canada to southern Texas, with acorns generally diminishing in size the farther north they grow, so some of the largest are likely to be found in this area. Burr Oaks are missing in western North America and most of the US Southeast, but extend eastward to Kentucky and New England.

Back in Kentucky where I grew up I was surprised to find Burr Oaks both in frequently flooded swamps around our farm and in thin, dry soil on limestone hills, but seldom in in-between habitats. I always figured that eventually taxonomists would recognize the presence of two look-alike Burr Oak species. However, though the online Flora of North America also mentions that in the northwestern part of the species' range Burr Oaks produce shrub forms on bluffs and hillsides, and that future study may find that such forms are different from tree-sized Burr Oaks, at this time, still, the general consensus is that all these variations are just different expressions of one variable species.

Though Burr Oaks do occur naturally in south-central Texas -- natural populations occur just a couple of counties east of here -- in Uvalde County here in the southwestern corner of the state, we're a bit beyond the species' natural distribution. Apparently it's too dry here for Burr Oaks. The tree in our photograph grew along a sidewalk in the town of Uvalde, having been planted there. In fact, Burr Oaks are seen as such desirable trees to plant that distinct cultivars have been produced through selective breeding, such as the 'Lippert,' the 'Boomer' and the 'Ekalaka Germplasm bur oak.'

One reason Burr Oak is so appreciated by many people is that its wood is one of the best of all oak species, similar to that of White Oak. Another admirable feature is that it provides food for deer, turkeys, squirrels, rabbits, raccoons, rodents and many other forms of wildlife, plus at maturity it makes a fine roosting, loafing, and nesting site for birds. Because Burr Oaks grow so tall -- up to 130 feet (40 m) -- and are so strong and fire resistant, they're preferred for planting as windbreaks.

Indigenous North Americans traditionally used Burr Oak medicinally to treat heart troubles, cramps, diarrhea, broken bones, to expel pinworms, and as an astringent (puckerer).

Our Burr Oak dark gray, flat-ridged trunk is shown at http://www.backyardnature.net/n/14/141005om.jpg.

*****

SOAPBERRY'S SMALL-FRUIT STAGE
At http://www.backyardnature.net/n/w/soapberr.htm we've admired the native Texas and tropical American Soapberry tree, showing its dense, dinner-plate-broad clusters of white flowers, its golden-grape-like fruits, and the way its fruit flesh froths up when beaten in water, but we've not seen what the panicle-type inflorescences look like between the stage of bearing very many small flowers and a few mature fruits.

To review, the stage with many small flowers is shown at http://www.backyardnature.net/n/13/130623sb.jpg.

That with a few mature, golden fruits appears at http://www.backyardnature.net/chiapas/soapber1.jpg.

Nowadays Soapberry fruiting heads show us the missing intermediate stage, seen at http://www.backyardnature.net/n/14/141005sa.jpg.

That picture shows that at this early stage, when fruits aren't nearly as large as they eventually become, already some are turning red and black, and falling off prematurely. It's a feature of their flowers' natural development that their ovaries are divided into two to four cells, each containing an ovule that will develop into a seed. As the ovaries mature into fruits, normally all but one cell aborts, leaving just one with its single ovule, and that cell matures into the tree's normal, one-seeded fruit. Seeing how these small, immature fruits are falling off, it looks as if many times all the cells abort, not just part of them.

The tree's pinnately compound leaves, which looks a lot like the locally abundant Pecan tree's similarly pinnately compound ones, are shown at http://www.backyardnature.net/n/14/141005sb.jpg.

*****

GIANT ASTER AT WATER'S EDGE
In mud beside one of the treatment ponds around which Cook's Slough Nature Park on Uvalde's south side is organized, a five-ft-tall (1.5m) mound of much branching, very slender stems and leaves gave the impression of being dense and impenetrable at its center, but so diffuse and airy at its surface that at a distance its tiny, white flowering heads seemed to hover around the plant without being connected to it. You can see the effect at http://www.backyardnature.net/n/14/141005as.jpg.

Up close, the flowering heads turn out to be of a classically aster type, though a bit on the smallish size. By aster-type is meant that the plant is of the Composite or Daisy Family, with flowering heads consisting of tiny, cylindrical, normally yellow disc flowers forming the head's "eye," and with many slender, normally white ray flowers radiating away from the eye. This plant's aster-type heads arose at the tips of remarkably long, slender, stiff-looking stems, or peduncles, as shown at http://www.backyardnature.net/n/14/141005at.jpg.

A close-up an "eye" consisting of only a few cylindrical disc flowers, with outside ones open -- each with regulation five, pointy corolla lobes -- while the center ones are still closed, is at http://www.backyardnature.net/n/14/141005av.jpg.

Seeing this plant, my first thought was that it was the largest, most vigorous-looking aster I'd seen in my whole life. I couldn't wait to identify it and see how rare and/or unusual it really was. Knowing that a huge number of aster species exist and that sometimes they can be hard to identify, I made sure to get a photo of the green, scaly, cup-like "involucre" from which the disc and ray flowers emerge, as seen at http://www.backyardnature.net/n/14/141005au.jpg.

Notice that this involucre's scales, or "phyllaries," are sharp-pointed with pale, cellophane-like (hyaline) edges, and that they're completely hairless (glabrous).

These and other features led me to an aster species that since my school days has been kicked into a genus other than aster, because someone broke the big, beautiful, easy-to-recognize genus Aster into several smaller, hard-to-remember ones. Our plant used to be Aster subulatus, but now it's SYMPHYOTRICHUM SUBULATUM, variously known as the Annual Saltmarsh Aster, Eastern Annual Saltmarsh Aster, Baby's Breath Aster, Bushy Starwort and other names. One reason it bears so many English names is that it's widespread, from South America north through Central America, Mexico and the Caribbean area, through all of the US except for the northwestern and north-central states, and into southern Canada. It's also escaped extensively on other continents.

Moreover, I've documented this species before, found growing from a fissure in a limestone rock at water's edge beside the Dry Frio, in mid December. You can see its eight-inch-tall (20cm), frost-bitten form then at http://www.backyardnature.net/n/13/131215a5.jpg.

How amazing that at the end of a growing season such a modest little being might in other summers and conditions soar head high! But note that the flowering heads and flowers of the dwarf and giant plants are exactly the same. That's how wildflowers normally are: The vegetative parts can vary wildly in shape and size, but the flowers and fruits typically remain amazingly uniform no matter what the plants' size and shape.

We can imagine how many tiny, cypsela-type fruits the prodigious numbers of flowers on our giant Cook's Slough plant produces, and that certain small, seed-eating birds might relish pecking at them. Livestock also eat the Saltmarsh Aster's herbage when nothing tastier is handy. The species is even capable of invading moist lawns where when mowed it assumes a leafy, ground-hugging form.

This mud-loving plant's toughness is to be admired. Its robustness is good to see. It's worth knowing.

By the way, according to the new way of thinking about the grand old genus Aster, members of the genus Aster are perennials, but members of the new genus Symphotrichum, to which our Saltmarsh Aster belong, are annuals. Thus our giant Aster at Cook's Slough did all that growing during our current growing season.

*****

NOT PETUNIAS
On my neighbor Phred's sundeck a bushel-basket-size potted plant has spent much of the summer spectacularly arrayed with pinkish blossoms. You can see a small corner of the plant with several flowers amidst numerous brown, curled-up remains of previous flowerings at http://www.backyardnature.net/n/14/141005ca.jpg.

All summer I've assumed that the plant was a special clumping, dwarf petunia. A blossom's side view displays the typical petunia flower shape at http://www.backyardnature.net/n/14/141005cb.jpg.

A pretty view into the blossom's mouth is at http://www.backyardnature.net/n/14/141005cc.jpg.

If you open up the blossom you see the petunia's special stamen arrangement, which consists of there being five stamens with two pairs displaying different lengths, and they all arise at the corolla's base, not halfway up the corolla tube, as shown at http://www.backyardnature.net/n/14/141005cd.jpg.

So, everything here says petunia, petunia, petunia... but when I began looking for a petunia cultivar looking like this, nothing came up. Eventually it grew clear that a closely related genus needed to be sought, though I'd not heard of such thing. However, such a genus does exist, one referred to by taxonomists as the genus Petunia's "sister group." The term sister group is applied to a taxonomic unit's closest relative. The assumption is that at some point during evolution a species "split," in our case one descendant evolving to become petunias while the other group produced offspring such as those turning up in a pot on Phred's sundeck.

Phred's sundeck plant is a member of the genus Calibrachoa, a genus that, like Petunia, is South American in origin but now much cultivated worldwide. Calibrachoa species look like Petunia species, but they don't interbreed -- thus constituting different genera -- if only because Petunia species have 14 chromosomes while those in Calibrachoa have 18.

On the Internet, plants looking like ours go by the binomal CALIBRACHOA x HYBRIDA 'MILLION BELLS.' The " x hybrida" means that two or more Calibrachoa species were hybridized to create our plant, and "'Million Bells'" is the cultivar name. A technical paper published in 2010 deals with 91 commercial Calibrachoa cultivars. The cultivars also come in various forms. For example, there's 'Million Bells Flamingo Pink,' which might be the one on Phred's sundeck, and 'Million Bells Apricot." And many cultivars further come in double flower forms, and/or trailing, mounding or more compact "bouquet" types.

So, if you can't check a plant's chromosome number, how do you know whether you have a Petunia or a Calibrachoa? I'm not sure that the non-expert can, though, in general, flowers on plants sold as petunias are larger and are less likely to mound up, while the Calibrachoa cultivars most commonly seen on sale produce small flowers, form dense mounds and flower prodigiously during all the warm season.

*****

FEATURED ESSAYS FROM THE PAST:

"How Pretty he Was" from the January 19, 2003 Newsletter, at http://www.backyardnature.net/n/p/030119.htm

"Altruism" from the April 28, 2007 Newsletter, at http://www.backyardnature.net/n/p/070428.htm

*****

Best wishes to all Newsletter readers,

Jim

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