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

June 8, 2014

NUTRIA
The small, intermittently flowing, sometimes almost non-existent Leona River runs through Uvalde's Memorial Park, where it's been widened into a small lake with a pleasant, mostly shaded walkway encircling it. From a small island in that lake a high-pitched, mammalian squeal made me look that way, where I saw the busy family scene shown at http://www.backyardnature.net/n/14/140608nu.jpg.

The squealing came from two immature critters tussling with one another among the island's weeds while a sibling looked on from the picture's far left. At the water's edge fourth juvenile reared on its haunches like a squirrel gnawing an acorn, while in the water a much larger adult floated in a patch of sunlight, emitting circles of little waves from its plant-chewing jaws.

Too small to be Beavers, at first I thought they might be Muskrats but, really, they were too large for that. The camera zoomed in on the brawling squealers revealing that their tails were round in cross-section, not flattened like a Beaver's, as you can see at http://www.backyardnature.net/n/14/140608nv.jpg.

The tail is shown in a more normal position, and you can see how much smaller and darker the youngsters are than the adult, at http://www.backyardnature.net/n/14/140608nw.jpg.

The rounded tail is more proof that we didn't have Muskrats, because Muskrat tails are flattened, used to help propel the Muskrat's body through water, like a flattened fish's tail. When this animal swam, the tail seemed to just go along for the ride.

Finally I remembered hearing that the Leona has been invaded by Nutria, and that's what we have: Nutria also are called Coypu after the Spanish CoipĂș, as well as River Rat, Swamp Rat and other names. They're MYOCASTOR COYPUS, originally native to subtropical and temperate South America, but now introduced into North America, Europe, Asia and Africa, mainly by fur ranchers. When you see how coarse their hair is you wonder how valuable the fur would be. A close-up showing a feeding adult's coarse hair is at http://www.backyardnature.net/n/14/140608nx.jpg.

However, as with many mammals, Nutrias produce various hair types. The unkempt spikiness shown by the adult in the picture is produced by "guard hairs." Below those there's an "underfur" regarded as very soft and plush, and often is used for linings and trims, and frequently dyed various colors.

In Louisiana the Nutria's ecological effect on coastal wetlands has been disastrous, resulting in an expensive Nutria Control Program conducted by The Louisiana Department of Wildlife and Fisheries. That agency produces an informative and interesting website dealing with Nutria history, wetland damage and biology at http://www.nutria.com/.

Nutria were intentionally introduced into Texas to control undesirable vegetation such as Waterhyacinth, and to give trappers something to trap. Now they're on Texas's list of top ten invasive species, right between fire ants and feral hogs. Next to their picture you read, "These pesky rodents feed on planted seedlings and saplings, and have consequently denuded hundreds of thousands of acres of marshlands and floodplains along the Gulf Coast. Efforts to regenerate destroyed regions have been futile, as nutria have been observed to decimate replanted vegetation even further."

An individual Nutria eats about one quarter of its body weight daily, feeds year-round, and because it prefers feeding on stems of aquatic plants, leaving leaves and shoots behind, it may waste 90% of the plant it eats.

So, one has mixed feelings about the Nutria family so easily observably on the island in Uvalde's city park. On the one hand, they're fascinating and fun to watch, but, on the other, it's worrisome to think what damage they and their descendents might inflict on the local environment.

*****

NURSERY WEB SPIDER
Our Memorial Day flash flood rearranged the Dry Frio River a little, scooping new depressions here, depositing new gravel bars there, and thoroughly obliterating many little green, scum-topped pools that for so long have provided teeming oases of life in a drought-stunned landscape.

In one spot where not long ago Water-willows, Justicia americana, emerged from a bone-dry bed of cobblestones, I was looking for emerging naiads on Water-willow stems now standing in fast-flowing, foot-deep water. I found none, but on a maturing Water-willow fruiting head I noticed the fair-sized spider in position atop her curious web shown at http://www.backyardnature.net/n/14/140608sp.jpg.

The web appears to be more a haphazardly connected network of silk strands than the elegant orb webs and funnel webs we often admire. The spider, being so close to water and so large -- the body without legs about about 10mm long (7/16ths inch) -- and with that conspicuous pale line traversing its front body segment, the cephalothorax, I felt sure that we had one of several species of fishing or water spider, of the Nursery Web Spider Family, the Pisauridae. However, it was different from the fishing spider species commonly seen resting on leaves floating on the Dry Frio's usually placid surface. You might enjoy comparing the above picture with that of our normally seen Six-spotted Fishing Spider archived at http://www.backyardnature.net/n/a/fishspid.htm.

A close-up of the brown and gray design on our Water-willow spider's abdomen is at http://www.backyardnature.net/n/14/140608sq.jpg.

Volunteer identifier Bea in Ontario nixed one after the other possible species it could have been in the same genus as our common Six-spotted Fishing Spider, Dolomedes, and then looked at other genera in the family. It turned out to be TINUS PEREGRINUS, which doesn't appear to have a commonly accepted English name, other than "nursery web spider," a general name applicable to all genera and species in that family.

Tinus peregrinus is distributed across the southwestern US from southern California to the southern tip of Nevada, and east to Texas and Missouri, and south into northern Mexico. A paper by James E. Carico on the genus Tinus, with maps and drawings, is freely available online at http://downloads.hindawi.com/journals/psyche/1976/079585.pdf.

Nursery web spiders in general are described as often semi-aquatic, sitting quietly for hours, legs spread out on vegetation or boat docks, or they may hunt actively in vegetation, and they have good vision.

*****

WILD PETUNIA
In a corner of the lawn of Uvalde's public library I met an old friend, pictured at http://www.backyardnature.net/n/14/140608rl.jpg.

This is one of several "Wild Petunias" of the genus Ruellia. Back in the Yucatan at the beginning of the dry season in November this same species grew outside the hut I stayed in, shown at http://www.backyardnature.net/yucatan/ruellia.htm.

There we called this species Mexican Wild Petunia because mostly it's distributed in Mexico, but in the US, where it occurs from Arizona to Louisiana but mostly in Texas, normally it's just called Wild Petunia. It's RUELLIA NUDIFLORA and it's not a petunia at all. The petunias grown in gardens are members of the Nightshade or Tomato Family, the Solanaceae, while Ruellia belongs to the Acanthus Family, the Acanthaceae.

About 25 Ruellia species are listed for North America and about ten conceivably could turn up here. Ruellia nudiflora stands out from all the others because its flowers are dispersed in a diffuse panicle at the top of the plant -- instead of being closer packed and often arising where leaves attach to the stems -- plus its flowers are dark lavender, not white to pale lavender.

An interesting feature of flowers of the genus Ruellia is that they're almost radially symmetrical, but not quite. A radially symmetrical corolla is one that can be cut down the middle in several directions, resulting in both sides of the cut being a mirror image of the other side. In contrast, bilaterally symmetrical corollas can be cut down the middle only one way so that mirror images result. Most flowers of plants in the Mint Family are bilaterally symmetrical. Our current Wild Petunia's slightly bilaterally symmetrical corolla is shown at http://www.backyardnature.net/n/14/140608rk.jpg.

Notice that the bottom corolla lobe is slightly larger than the others, which wouldn't be the case in a radially symmetrical corolla. A shot of the corolla from the side is at http://www.backyardnature.net/n/14/140608rj.jpg.

There you can see that the corolla tube very slightly curves downward. A radially symmetrical corolla wouldn't that.

At http://www.backyardnature.net/n/14/140608ri.jpg a Ruellia nudiflora corolla has been split open to show the flower's four paired stamens on the picture's right side, and the single long, slender style at the left.

This particular wild petunia species grows weedily in Uvalde, in abandoned lots, along streets, at the water's edge of the Leona River in Memorial Park and elsewhere. At this time of year it's one of the most conspicuous native wildflowers and I'm glad it's tough enough to compete with the usual invasive weeds. The species grows easily from seeds, so in this area it would make sense to collect seeds when the fruits mature in a few weeks, and sown in unmowed places around the house.

*****

BUR MEDICK
A small, sprawling weed showing up along streets and other very disturbed areas in Uvalde is shown at http://www.backyardnature.net/n/14/140608mg.jpg.

With such clover-like, trifoliate leaves -- leaves divided into three leaflets -- you can guess that this is a member of the Bean Family, which it is. A close-up shows that the tiny, hardly opening flowers display the general Bean Family "papilionaceous" shape at http://www.backyardnature.net/n/14/140608mh.jpg.

This is one of several species of the genus Medicago, commonly known as medicks, though the very important forage plant Alfalfa also is a Medicago, M. asiatica. Medicago species are generally recognized as small, weedy herbs looking more or less what's in the pictures. The species we're looking at is distinguished from other Medicago species by the hairiness of its leaves and stems and, most importantly, the spiky appearance of its fruit, seen at the lower, left in the last photo. Fruits of most species are smooth, shaped like flattened cloth coin-purses, or sometimes coiled like snail shells.

Its hairiness and spiky fruits distinguish this little herb as MEDICAGO MINIMA, known variously as Bur Medick, Little Burclover, Little Medick, Small Medick, Woolly Bur Medick, and by other names. All medick species are invasive in North America, originally coming from Eurasia, especially the Mediterranean region.

Despite the Bur Medick being a genuine invasive weed, it's worth tipping the hat to. That's because it forms a symbiotic relationship with the bacterium Sinorhizobium meliloti, which can fix nitrogen, thus basically fertilizing the soil, helping other plant species eventually root themselves and prosper. I think of Bur Medick as a classic first responder. People destroy soil structure and nutrient content, and Bur Medick comes in generously offering everyone life-supporting nitrogen.

*****

TEXAS OLIVE
Along Main Street in Uvalde here and there they've planted some small, dense trees about the size and shape of healthy, well watered apple trees, but bearing largish, egg-shaped leaves and -- at least during the last few weeks -- white, yellow-throated, funnel-shaped flowers two inches across (5cm). Flowering season is almost over and this week I had to look around to find a single flower, but that one is shown at http://www.backyardnature.net/n/14/140608cd.jpg.

The trees are heavy, however, with developing, drupe-type fruits covered with fuzzy, baglike calyxes, a cluster of which is shown at http://www.backyardnature.net/n/14/140608ce.jpg.

We've seen this tree before, not planted along a busy highway but growing naturally and very prettily -- though smaller, much less dense and more gnarly -- on a hot, dry, scrubby slope in Querétaro, north-central Mexico. There we learned to call it Anacahuite, but in these parts it's called Texas Olive, or Mexican Olive, though it's not related to real olive trees. It's also known as White Geiger Tree. It's CORDIA BOISSIERI, a member of the Borage or Forget-me-not Family, a family that to most Temperate Zone folks is known more for its herbaceous members than its woody ones.

Texas Olive's native range is mainly arid northeastern and central Mexico, but it extends into Texas. I'm unsure whether we're within its native range. Though it certainly prospers in Uvalde, here it loses its leaves after hard freezes, but in Mexico manages to be an evergreen.

Though the fruits are sweet, I read that they're slightly toxic when fresh, causing dizziness in humans and other animals. Still, jellies made from the fruits seem to be safe. Syrup extracted from the fruits is used to dye cloth and treat coughs. Traditionally the leaves have been used medicinally for "rheumatism" and lung ailments. The wood is used as firewood and for carpentry.

And it does good service making things pretty and adding some greenery along Uvalde's Main Street.

*****

RED YUCCA
Last month we admired the red-flowered Soap Aloe abundantly planted around houses and along streets in Uvalde, still profiled at http://www.backyardnature.net/n/h/soapaloe.htm.

Now just as commonly planted another agave-type plant with waist-high clusters of red flowers on leafless stalks is putting on a similar show. You can see such a plant beside the parking lot of Uvalde's fine public library at http://www.backyardnature.net/n/14/140608he.jpg.

At first glance the fowers are very similar to those of our earlier Soap Aloe, as shown at http://www.backyardnature.net/n/14/140608hh.jpg.

A longitudinal section showing how the stamens are affixed by their filaments to the bottom of the red perianth tube is at http://www.backyardnature.net/n/14/140608hi.jpg

An egg-shaped, capsular fruit that eventually will split along its sutures to release numerous dark seeds is shown at http://www.backyardnature.net/n/14/140608hg.jpg.

These features are so similar to those of our previous Aloe that one of the fathers of American botany, Asa Gray, thought the species was indeed an Aloe, and named it Aloe yuccaefolia, a name meaning "Aloe with yucca-like leaves."

But, those yucca-like leaves are so different from those of succulent aloes that maybe Gray should have been more careful. The blades not only are hard like yucca leaves but also many pale, hairlike filaments conspicuously curl away from the blade margins, exactly as in many yucca species, as shown at http://www.backyardnature.net/n/14/140608hf.jpg.

So, who is this plant whose leaves look like those of yuccas, but whose flowers aren't at all like yucca flowers? You might want to review the flower of one of our local Spanish-Dagger yuccas here, Yucca treculeana, at http://www.backyardnature.net/n/14/140330yv.jpg.

Our Uvalde plant with red flowers like an aloe but hard, stiff leaves like a yuca, is neither a yucca nor an aloe, but rather HESPERALOE PARVIFLORA. Sometimes the five Hesperaloe species are known as false yuccas, but really there's no decent English name for them. The most commonly used English names for Hesperaloe parviflora are Red Yucca and Hummingbird Yucca, which is a shame because they're a long way from being yuccas.

Whatever common name we apply to the species, in the hot, arid, southwestern US states this plant has become very popular in xeriscape gardening and landscape design not only because of its prettiness but also for its drought tolerance, heat resistance, and low maintenance needs. Often xeroscapers regard it as a spineless alternative to Agave and Yucca horticultural species.

The species evolved these admirable qualities as it adapted to life in its native distribution area, which was mainly arid northern Mexico and contiguous southern and western Texas. Its exact native distribution is uncertain, however, because for such a long time it's been propagated by people outside its native haunts, just because it's so pretty.

*****

FLOWERING ARTICHOKE
Artichoke plants, CYNARA SCOLYMUS, are thistles, and members of the Composite or Daisy Family. The green, burry items many people like to eat are the Artichoke plant's flower buds -- the buttonlike stage a flower exhibits before it blossoms. In 2009 during our summer in Oregon, a neighbor grew Artichoke plants and we got to see what the Artichoke's edible flower buds look like still attached to their mother plant, and a picture of that is at http://www.backyardnature.net/n/h/artichok.htm.

In our many surveys of members of the Composite Family, often we've referred to green "involucral bracts," which form a bowl-like structure below a flowering head's tiny composite flowers. Those green things, the involucral bracts, are what we pull from the burry, cooked artichoke on our tables so we can pull them between our teeth to make tasty pulp extrude into our mouths. Involucral bracts are what make the Artichoke plant's flower buds look so burry. On most thistles the involucral bracts are spiny, and even the Artichoke plant's edible involucral bracts bear single spines at their tips. To get better oriented about involucral bracts, you might like to review a weedy, Nodding Thistle's head with spiny involucral bracts at http://www.backyardnature.net/n/13/130519ce.jpg.

Most gardeners who grow artichokes cut off the flower buds to eat, so the Artichoke plant never produces flowers. My neighbor Deborah, though, just wanted her plants to be pretty and happy, so she let them grow as they pleased, and was rewarded with the pretty thistle heads seen at http://www.backyardnature.net/n/14/140608as.jpg.

You just can't miss the general similarities between the heads of the weedy Nodding Thistle and those of the Artichoke. A close-up of a single Artichoke flowering head being visited by a Pipevine Swallowtail butterfly is at http://www.backyardnature.net/n/14/140608ar.jpg.

*****

JUNE SYCAMORES
After our big rain on Memorial Day the Dry Frio is running again. Until now along the river's dry stretches the Sycamores' leaves weren't expanding with their usual springtime abandon. They looked cramped on their branches, maybe a bit stunned by endless days without rain. And then the flood brought so many changes into the landscape that I stopped noticing them.

However, the other day I stretched out on gravel beneath a big Sycamore along the river and found myself looking up into a blue sky framed by fully unfurled, sunlight-glowing Sycamore leaves, and I was surprised by how fast the leaves had developed in just a few days, and by how beautiful, and vigorous they looked. You can see exactly the leaves I saw then at http://www.backyardnature.net/n/14/140608sy.jpg.

A light breeze streamed up the river causing the leaves to quake and sometimes bend to the side, so what's missing in that picture is the shadows moving about and sunflecks coming and going, the leaves twisting back and forth on their slender petioles, the rustling sound of leaves in a light breeze, and the odor and feeling of a morning moving toward midday.

There was another feeling, too, a more profound one. That feeling was compounded of memories and associations from many times having seen and experienced Sycamore leaves in their vigorous, perfect June state, and the way I've always felt in those Junes.

For, in June I do feel a certain way. It's the spring-turning-to-summer feeling, the feeling of another whole, long summer ahead, the uncertainty of how to handle it, but also the hunger to plunge into it, and to deal with it my own way. But, after being so many different ways through so many summers, what is my own way now?

One soothing feature of Sycamore leaves resplendently glowing in June sunlight is that you can so plainly see that the Sycamore already has its summer figured out, and has already gotten to work on it: Its plan is to keep photosynthesizing, keep gathering energy for producing flowers and fruits, while all the time dealing with insects, diseases and storms, and preparing for winter, and to do all this with a certain flair, which is pretty to be in the presence of.

As I lie on my back seeing fresh June Sycamore leaves with the rain-washed, blue sky beyond, then, metaphorically I'm being offered a paradigm suggesting a way to get through at least these next few monthd, and do it prettily.

What a pleasure lying on one's back, looking up into the sky occupied with sunlight-glowing Sycamore leaves in June. What a gift that even in the late October of one's life, there remain Junes with Sycamores, sunlight and wind in them.

*****

FEATURED ESSAYS FROM THE PAST:

"Standing Up For Clover" from the March 30, 2009 Newsletter, at http://www.backyardnature.net/n/p/090330.htm

"Eating Green" from the February 23, 2009 Newsletter, at http://www.backyardnature.net/n/p/090223.htm

*****

Best wishes to all Newsletter readers,

Jim

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