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

April 6, 2014

SCISSOR-TAILED FLYCATCHERS HAVE ARRIVED
Lots of bird migrants have arrived in our area, but one of the most spectacular is the Scissor-tails, shown at http://www.backyardnature.net/n/14/140406fc.jpg.

On a windy afternoon with the temperature in the upper 80s, this one perched on a wind-swung wire where he could overlook a big wheat field. The wind moved the wheat in big, slow waves, like the ocean, and the Scissor-tail seemed to like it. Every minute or so he'd fly out over the wheat, spreading his tail into a wide V. That would have made a fine picture, but he was too fast for me.

Scissor-tails overwinter in southern Mexico and along the Pacific coast south to Panama, and nest in the US south-central states, from southern Nebraska and Missouri into northeastern Mexico. It's good to see them again here.

*****

JERUSALEM-THORN'S OTHERWORLDLY LEAVES
The Jerusalem-thorn, PARKINSONIA ACULEATA, is a small tree native from central Texas south as far as northern South America and west to Arizona. A member of the Bean Family, later in the year it'll produce pretty clusters of yellow flowers, but right now it's only issuing leaves. However, the leaves are so strange-looking that they deserve attention just by themselves. You can see them issuing from spiny stems at  http://www.backyardnature.net/n/14/140406pk.jpg.

Each of the items you might think is a pinnately compound leaf is actually one of two of a leaf's subdivision, and that subdivision, or pinna, is then further divided into the small, widely spaced leaflets you see. The twice-compound leaf has a very short stem, or petiole.

I've not seen Jerusalem-thorns along the upper Dry Frio but in the scrub around Uvalde 35 miles to the south and lower in elevation, they're common. Other names for Jerusalem-thorn include Paloverde, Retama and Lluvia de Oro.

Jerusalem-thorn is a member of the huge Bean Family. The "Jerusalem" in its name is what English speakers came up with when they heard Spanish speakers call it "Girasol," which in the name usually given to sunflowers, and means "turning toward the sun."

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FALSE DAYFLOWER
Uvalde's Memorial Park with ponds and shady, winding paths is as pretty and well maintained as you could wish, but down at the far end along the little Leona River's banks, a little part doesn't get mowed, the vegetation is lush, and at this time of year when winter is such a fresh memory, that green, rampant lushness is good to see. The usual weeds are to be found there, but one caught my special attention, shown at http://www.backyardnature.net/n/14/140406df.jpg.

With its broad, grass-like leaves and purplish flowers with bilateral symmetry looking like little doll faces with bulging eyes and whitish mouthparts, an average wildflower sniffer instantly recognizes this as one of several weedy dayflower species. However, back at Juniper House when the pictures were on the laptop, I was shocked to see something extraordinary in the flower close-up. See if you can spot it at http://www.backyardnature.net/n/14/140406dg.jpg.

I didn't recall flowers on dayflower species being so long-hairy on their stamen filaments. Moreover, the online Flora of North America description for the dayflower genus, Commelina, states flatly that in dayflower blossoms the filaments are "glabrous," which means "hairless." Filaments in the picture are so audaciously hairy that I went to the Flora's general key to the Spiderwort Family, the Commelinaceae, to which dayflowers belong, and keyed out the plant from the beginning.

And, behold, there was a genus I'd never heard of, practically identical to the Dayflower Genus Commelina, except that in regular dayflowers there are only three fertile stamens, while in this other genus, there are six, and while the three stamens of the dayflower have hairless filaments, this other genus' six stamens are "densely bearded," as the Flora says.

Our little Uvalde weed is TINANTIA ANOMALA, aptly known as the False Dayflower. In the whole world it occurs only in several southern and central Texas counties, and a little part of adjacent Mexico. The Flora of North America describes its habitat as "limestone talus slopes, granitic slopes, edges of woods and ravines, prefers some shade."

The genus Tinantia is home to about fourteen species, of which only our False Dayflower occurs in North America, the other species being limited to tropical America, especially from Mexico to Nicaragua. The False Dayflower represents the genus Tinantia's effort to diversify into cooler regions.

What a pleasure to discover that what at first seemed very ordinary was in fact something I'd never seen!

*****

BRISTLEMALLOW
In Uvalde's pleasant Memorial Park, down in the grass next to a duck pond, so small and low-growing that mowers have passed right over it, a certain plant bore a bright, red-orange flower with a yellow center, the whole blossom only about the size of a mouse's eye. On hands and knees and squinting into the grass, it was clear that this little plant was worth knowing. You can see it at http://www.backyardnature.net/n/14/140406mo.jpg.

Seeing how the flower's numerous stamens created a kind of bouquet with the yellow anthers' dark red filaments joined at their bases forming a cylinder around the pistil's style, already it was clear that this was a member of the big Hibiscus Family, the Malvaceae. A look at the back of the little flower is seen at http://www.backyardnature.net/n/14/140406mp.jpg.

That picture shows that the five hairy calyx lobes unite at their bases into a kind of bowl, and that below the calyx there are leaf-like "bracts." These details help in the identification of the species.

This is such a pretty, common and distinctive little plant that identifying it wasn't hard, despite not having fruits, which often are needed when figuring out the name of Hibiscus Family species.

In the US our plant is mostly known as the Carolina Bristlemallow, though as a "weed" occurring in much of the world it goes by many names. It's MODIOLA CAROLINIANA, and it's such a distinctive plant that it's the only species in the genus Modiola. It's thought to be native to tropical America, from northern Argentina north to the warmer parts of eastern North America, and if that's right, then it's at home here, even in mowed grass next to a park's duck pond.

One reason it's so weedy in so many places is that it's a tough little plant, tolerant of both salt and drought. There are reports of livestock being poisoned eating its herbage. However, in Daniel Austin's "Florida Ethnobotany," it's reported that Carolina Bristlemallow has been used as a gargle for sore throats, tonsillitis and diphtheria; as an emollient and sedative, and to treat edema.

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DUCKWEED
On Uvalde's south side, ponds have been dug for recycling the town's used water. The area consists of interconnected ponds separated by tracts of arid scrub, and has been designated as Cooks Slough Sanctuary & Nature Park. It's a pleasure to walk among the ponds spotting waterfowl and, right now, smelling the heavenly fragrance of flowers of Huisache, or Sweet Acacia, currently at their peak of flowering and looking like elephant-size, yellow-orange bouquets.

Despite the abundance of ducks, these days there's only a little duckweed -- those green, oval, tiny, aquatic plants that float atop certain quiet bodies of water, like green confetti. You can see some at a pond's edge at http://www.backyardnature.net/n/14/140406dw.jpg.

Several duckweed species might be found in our area, so naturally it's good to know which one this is. The ID process began by getting some plants onto my fingertip, shown at http://www.backyardnature.net/n/14/140406dx.jpg.

The first decision to make is whether this is the main duckweed genus, Lemna, in which many species are found, or another, smaller genus. To settle this first issue, one important field mark to notice is the number of veins in each frond. In these plants the veins are faint, only three per frond showing plainly, but if you study closely, assuming that veins occur in the fronds' bottom sections where no veins are visible, you might decide that at least seven to nine veins are present. Fronds of the main duckweed genus, Lemna, normally have only one to five veins, rarely seven, so this is a hint that we have something other than Lemna. Below, the plant shows another important field mark. You can see it at http://www.backyardnature.net/n/14/140406dy.jpg.

The whitish, hairlike items are roots that dangle into the water. Lemna fronds produce only one root per frond. This frond has five or six, so this must be something other than the common duckweed.

The Flora of North America recognizes four genera in the Duckweed Family, the Lemnaeae. Plants in two of those genera produce no roots at all, so if we don't have Lemna, that leaves just one duckweed genus, that of Spirodela. Our plants with their five to seven veins, and five or so roots key out to SPIRODELA PUNCTATA.

This isn't the common Spirodela species I was expecting, Spriodela polyrrhiza, which is a native species. However, in Mississippi I've run into this one, an invasive species thought to be from Eurasia and Australia. The species seems to be invading the US fast, and I'm guessing that it's expanding into our area now. It's hard to be sure about these IDs so without growing them in a lab and looking at them under the microscope, this is just an educated guess.

Whatever the case, I'm glad to be able to post these pictures under the Spirodela punctata name, for,later, certainly researchers will be glad to have any information about how this invasive is spreading.

*****

WHEAT
Wheat fields can be seen here and there around Uvalde. A lush, green field will stand right beside native scrub forest adapted for semi-desert conditions, and the contrast is striking. You can see wheat plants at the edge of a large field at http://www.backyardnature.net/n/14/140406tr.jpg.

Common Wheat, which is the third most-produced cereal on earth after corn, or maize, and rice, is TRITICUM AESTIVUM. Several species of the genus Triticum are sometimes grown for food. For example, Durum Wheat, Triticum durum, is the second-most planted wheat species, after Common Wheat, and produces an exceptionally hard, light-colored grain used to make semolina flour for pasta.

Within the Common Wheat species there's enormous variation. In fact, Common Wheat is a concoction of various species; there's no single wild ancestor to Common Wheat. During the last 10,000 years, humans have produced Common Wheat, Triticum aestivum, from a variety of genetic sources. It's enough to point out that, genetically, Common Wheat is an "allohexaploid," which means that it contains six sets of chromosomes, two sets from each of three different ancestral species.

One of the most obvious differences between the different Common Wheat varieties is that some varieties produce heads of spikelets bearing long, needle-like awns, while other varieties are awnless. Holding a head of one of our Uvalde plants up for a look, it was easy to see that the variety in this produced very substantial awns, shown at http://www.backyardnature.net/n/14/140406ts.jpg.

That head consists of 15 or so spikelets, which attach to the stem, or "rachis," alternating with one another, so that the first spikelet from the bottom has above it the third spikelet, while the second spikelet from the bottom is below the fourth spikelet, and so on up the rachis. A close-up of one spikelet containing five or so florets, with yellowish, pollen producing anthers dangling outside, is at http://www.backyardnature.net/n/14/140406tt.jpg.

Several hundred wheat varieties are recognized, and they all can be assigned to one of six basic wheat classes. They are: hard red winter; hard red spring; soft red winter; durum; hard white and; soft white. Texas A&M University operates an Agricultural Research and Extension Center at Uvalde, and several studies have been conducted in the area, focusing on varieties that can grow best in our unusually hot environment.

"Spring wheat" and "winter wheat" are not varieties or wheat classes, but rather just wheat that's grown at certain times of the year. Winter wheat, which normally accounts for 70 to 80 percent of U.S. production, is sown in the fall and harvested in the spring or summer; spring wheat is planted in the spring and harvested in late summer or early fall. Therefore, our picture taken in the spring shows "winter wheat."

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FEATURED ESSAYS FROM THE PAST:

"The Maidu" from the August 21, 2005 Newsletter, at http://www.backyardnature.net/n/p/050821.htm

"Yin & Yang of JalapeƱo" from the October 18, 2009 Newsletter, at http://www.backyardnature.net/n/p/091018.htm

*****

Best wishes to all Newsletter readers,

Jim

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