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

July 7, 2013

BLACK-CRESTED TITMICE
Tufted Titmice are among the most common and best known of songbirds in the eastern US and southernmost Canada, but from what I've seen so far we don't have them here. We do have plenty of titmice, but they're Black-crested Titmice, BAEOLOPHUS ATRICRISTATUS, such as the one shown at http://www.backyardnature.net/n/13/130707tu.jpg.

Our Black-crested ones look like, sound similar to and behave like Tufted Titmice -- other than that their tufts are black, not gray. Our Black-crested ones look like, sound similar to and behave like Tufted Titmice -- other than that their tufts are black, not gray. You can compare the above picture with that of a Tufted Titmouse back in Mississippi at http://www.backyardnature.net/n/b/tuft-tit.htm.

Also, notice that the forehead -- the area immediately above the beak -- on our bird is white, while Tufted Titmice foreheads are black. However, the crests of immature Black-crested Titmice are not black, as shown by one about to scratch with his beak beneath his raised wing at http://www.backyardnature.net/n/13/130707tt.jpg.

My dog-eared 1966 field guide recognizes Black-crested and Tufted Titmice as different species, but during much of my birding career the two have been lumped, with our black-crested birds being considered a mere variation of the Tufted Titmouse. However, as of 2002 most authorities have begun separating the two species again. The USGS, whose distribution maps pop up when you do a search on bird species, continues to lump the two populations on the basis of hybridization occurring in central Texas and southwestern Oklahoma.

Michael Overton's "Birds of Uvalde County, Texas" checklist shows Black-tufted Titmice as abundant here throughout the year, but Tufted Titmice are not listed at all.

Our Black-crested Titmice seem to me a bit less trusting than the East's Tufted Titmice. Black-cresteds are less likely to flit close when squeaking or pishing sounds are made to attract them. At the birdfeeder, unlike House Finches and Chipping Sparrows who stay and gorge, our Black-crested Titmice flit onto the feeder, snatch a seed and immediately fly to the nearby woods to eat it.

*****

TEXAS MIMOSA
Just a couple of miles south of here and lower on the Edwards Plateau slope certain scrubby, usually spiny, acacia-like bushes appear that are typical of the hotter, drier scrubland farther south and west but rare or absent around the Center. One such spreading, much-branched, shoulder-high shrub that nowadays is both flowering and fruiting is shown along the road at http://www.backyardnature.net/n/13/130707mn.jpg.

A ¾-inch broad (2cm) flowering head among the bush's ferny, twice-compound leaves appears at http://www.backyardnature.net/n/13/130707mo.jpg.

That flower head consists of numerous blossoms attached to the tip of a stem-like peduncle. The numerous slender items radiating outward are stamen filaments topped by tiny, spherical, pollen-producing anthers. This is a typical flowering head of a certain group of Bean Family members, the group including such well-known plants as the acacias and mimosas that are so typical of the arid American tropics and subtropics. Since the bush is a member of the Bean Family, it bears legume-type fruits. Legumes on this bush are very distinctive, as shown at http://www.backyardnature.net/n/13/130707mm.jpg.

Upon first seeing this bush I thought we'd already profiled it, in our recent April 21 Newsletter, identifying it as the Pink Mimosa, Mimosa borealis. However, when I double checked the matter, this week's roadside bush turned out to be something else. It's a mimosa, but it's the Texas Mimosa, MIMOSA TEXANA, endemic just to southwestern Texas and adjacent arid, upland Mexico.

To see why it might be so easy to confuse the two species, you might like to compare the above pictures with those of last April's Pink Mimosa at http://www.backyardnature.net/n/w/mimosa-b.htm.

I was helped in distinguishing the two very similar, closely related species by a webpage produced by the University of Texas dedicated entirely to telling the two species apart. That page is at http://www.biosci.utexas.edu/prc/digflora/mimosa/mimosa-dif.html.

Among other features, that page points out that flower corollas of last April's Pink Mimosa produce petals separate from one another all the way to their bases. You can see this in our flower picture of that species at http://www.backyardnature.net/n/13/130421mn.jpg.

Compare those corollas with those of this week's Texas Mimosa, which join at their bases to form a short tube, at http://www.backyardnature.net/n/13/130707mp.jpg.

Also, the legumes of Pink Mimosas arise on relatively long, slender stems, or "stipes," while the bases of legumes of Texas Mimosas are short and thick, as shown at http://www.backyardnature.net/n/13/130707mq.jpg.

So, this was a fine find, a shrub with fragrant, pretty blossoms, of very limited distribution, and hard to notice unless you're paying attention to such details as how much the petals are attached at their bases.

*****

FOGFRUIT/ FROGFRUIT
We're in the midst of a long drought here but we did get a good rain a couple of weeks ago, so now the landscape is fairly green and certain wildflowers that have held back during the spring now are flowering. One very common weedy plant growing in hard-packed soil along roads and similar disturbed areas is the ankle-high, mat-forming plant with pea-sized flowering heads at http://www.backyardnature.net/n/13/130707ph.jpg.

At http://www.backyardnature.net/n/13/130707pi.jpg a close-up of a flowering head shows that the individual flowers bear four corolla lobes, the top and bottom ones being larger and slightly different in shape from the side ones, so that the corollas are somewhat bilaterally symmetrical. The flowers' corolla throats at first are yellow but as they age they turn reddish. In the picture, peeping from the throat of the flower facing us you can see two of the flower's four anthers.

Below the line of flowers encircling the top of the flowering head, the brown, shriveled items are old corollas of flowers already pollinated. Above the circle of flowers, the purplish "dome" consists of overlapping bracts, or modified leaves, beneath each of which lies an immature flower. When the current flowers are pollinated and their white corollas shrivel and turn brown, new flowers will emerge just above them, from beneath their respective bracts. This will cause the region of brown, shriveled corollas below to elongate while the purple dome will become a little lower. The immature head starts out more or less spherical and purple, but ends up long and brown, with fruits maturing beneath the layer of brown, shriveled corollas.

This unusual combination of field marks is diagnostic of a certain very common, easy to recognize genus of plants in the Verbena or Vervain Family, the Verbenaceae: the genus Phyla. Plants in the genus Phyla are normally referred to as fogfruits or frogfruits, and I wish I knew how the genus got stuck with those two names. Wildflower.Org's "Ask Mr. Smarty Plants" page says that the name fogfruit probably predates frogfruit by about 100 years (early 1800’s for fogfruit vs. early 1900’s for frogfruit), and the expert visualizes a wildflower book editor a long time ago making an error.

The various species of fogfruit/frogfruit/genus Phyla --of which about seven are listed for North America -- can be hard to distinguish. In Uvalde County two species are commonly encountered and two more might turn up here. Ours keys out to -- and matches photos on the Internet of -- PHYLA FRUTICOSA, commonly listed in wildflower books as the Diamondleaf Fogfruit.

Our Diamondleaf Fogfruit is a mostly tropical American species extending into the US in Texas, Louisiana, a bit of New Mexico, and southern Florida. It's become a weedy invasive in several countries in other parts of the world.

The main field mark distinguishing it from other species is that its leaves are widest at about their middles, not toward their outer ends, and the leaves' teeth normally begin in the lower half of the leaf, again not on the outer end. A typical Diamondleaf Fogfruit leaf is shown at http://www.backyardnature.net/n/13/130707pj.jpg.

Older books often assign Phyla species to the genus Lippia.

*****

THE ROCK-LOVING SLENDER GREENTHREAD
So many wildflowers similar in appearance are flowering after the rain of two weeks back that it's hard to keep them all straight, especially all the yellow-blossomed members of the Composite or Daisy Family. However, when I saw a certain one this week -- despite it being yet another yellow-blossomed member of the Composite Family -- I knew I'd never encountered it before. You can see it leaning from a fissure in a shaded limestone cliff at http://www.backyardnature.net/n/13/130707th.jpg.

Having something new, immediately I set about "doing the botany":

The plant's leaves arose two per stem node, opposite one another. Many of the upper leaves were mere slender filaments but some lower ones were deeply pinnately lobed, the lobes being threadlike, as shown at http://www.backyardnature.net/n/13/130707tk.jpg.

From above, the flower heads show nothing special, but from the side suddenly you see a very interesting field mark, as shown at http://www.backyardnature.net/n/13/130707ti.jpg.

The yellow flowers arise from within a very unusual involucre -- the bowl-like thing in most flowers composed of green, sharp-pointed scales or bracts that overlap one another like roof shingles. In the above photo we see that the scales of this flower head's involucre are of two very different types. At the bottom there's a row of several green, slender, blunt-tipped scales, or "phyllaries," then above them arise another series of very much larger, pale phyllaries, the tips of which extend up between the yellow corollas of the head's ray flowers. These larger, inner phyllaries are slightly pink with thin, white margins. Having two rows of such different-looking phyllaries is an excellent field mark, a very unusual but not unheard-of arrangement.

Breaking open a head, it was easy to see that between each disk flower a thin, cellophane-like scale or bract partly enveloped the developing ovary and lower part of the corolla, as seen at http://www.backyardnature.net/n/13/130707tj.jpg.

With such a collection of distinctive field marks it was easy to "key this species out" to THELESPERMA SIMPLICIFOLIUM, in wildflower books commonly called the Slender Greenthread, as well as Navajo Tea, Hopi Tea, Indian Tea and Cota. The online Flora of North America describes its habitat as "Openings in oak/juniper woodlands or desert scrub, usually on limestone," but here so far I've only seen it on limestone cliff faces. Slender Greenthread mostly occurs in arid northern Mexico but extends into the US in Texas and New Mexico.

Nine Thelesperma species are found in North America, all restricted to dry habitats and mostly at home in the US south-central states. As some of the plant's common names imply, several Thelesperma species, including our simplicifolium, have been used traditionally by various Native American groups as tea, referred to in English as greenthread tea. Our plants are so uncommon that I'd never pick them for use as tea, but I read that greenthread tea tastes something like standard green tea, with a very slight aromatic taste, and thus can be enjoyed without sweetener.

In fact, greenthread tea is sold commercially. You might enjoy browsing a web page produced by Oregon's Institute for Traditional Medicine describing how the various Thelesperma species are used, how the tea is prepared, and what compounds are found in it, at http://www.itmonline.org/arts/greenthread.htm.

*****

SPIDER MILKWEED FRUITING
You might recall the handsome Spider Milkweed flowering along our roads back in May. You can review what a flowering one looked like then at http://www.backyardnature.net/n/h/spidmilk.htm.

Now they're fruiting, as shown at http://www.backyardnature.net/n/13/130707as.jpg.

In that picture the follicle-type fruit is splitting down one side in preparation for parachuted seeds to be released into the wind. A follicle-type fruit is one that results from a simple pistil, is dry, not fleshy like a peach, and when ripe opens along one side.

*****

PIGWEED BESIDE THE CABIN
Most wildflowers and weeds draw attention to themselves with their flowers, but flowers of the leg-tall herb growing next to the red cabin in the valley are so small that even when you look for them it's hard to find them, despite there being thousands and thousands of them. You can see the plant at http://www.backyardnature.net/n/13/130707am.jpg.

The greenish, crumbly-textured "spikes" atop each of the plant's branches are flowering heads composed of multitudinous flowers about 1/8th inch tall (3mm). The vast majority of the blossoms are female, with only a few male flowers clustered at flowering branch tips. You can see both flower types as observed beneath a dissecting scope at http://www.backyardnature.net/n/13/130707ao.jpg.

In that picture the female flower at the left displays at top, center one of its three white, curving stigmas. Two of three to five pollen-producing anthers dangle outside the male flower at the picture's right. Modified leaves called bracts subtend each flower. In the image of the female flower at the left, that long, sharp-pointed, green thing at the right is a bract. Immediately to the left of that bract arises one of the flower's tepals -- "tepals" being the term used to designate petal-like items serving as both calyx lobes and corolla lobes or petals.

In that image of the female flower, notice that the tepal to the left of the bract bears a tiny, sharp, white spine, or "mucro," at its tip, but just below the mucro the tepal's top expands so that in general shape the tepal is blunt or somewhat squared at the top, even with a couple of "ears" between which the mucro arises. These obscure details are important field marks because they help us distinguish two look-alike, common, widely spread weeds.

Both the weeds are known generally as pigweeds, and they belong to the amaranth genus, Amaranthus. East of the Mississippi mainly I've met with Amaranthus hybridus, but that species' tepals gradually come to a sharp point at their tops, with no ears or mucros. The other species, ours, having those ears and mucro, is AMARANTHUS RETROFLEXUS. In books Amaranthus retroflexus is given many names other than just "pigweed," such as Redroot Pigweed, Redroot Amaranth, Wild-beet Amaranth, Rough Pigweed and Common Amaranth.

Members of the genus Amaranthus are indeed amaranths, the very ones that various cultures worldwide regard highly as leaf vegetables, cereals, and ornamental plants. In Mexico a popular, traditional, sweet, cookie-like item called alegría is made from amaranth seeds toasted until they pop, then glued together with crystallized syrup, and sold in plastic bags. If you shake a section of flowering head from the plant in the picture over the palm of your hand, dozens of tiny, straw-colored fruits collect in your hand. Then if you smush the fruits with your finger, shiny, black seeds pop from their husks, as shown at http://www.backyardnature.net/n/13/130707an.jpg.

Both of the look-alike pigweeds are native American species who display unusual ecological adaptability, which has enabled them to become weeds worldwide. Most of North America's weeds are Eurasian, so this is one instance when North America is sending weeds to the rest of the world. Our Amaranthus retroflexus is native to central and eastern North America.

*****

DALLISGRASS
Up against the red-painted wall of the valley cabin I lived in this winter nowadays a handsome grass is flowering, shown at http://www.backyardnature.net/n/13/130707pp.jpg.

The manner by which the slender, green "fingers" dangle from tips of the main stems and are well separated from one another along the stem top constitutes a good field mark for a large group of common grasses often referred to as the paspalums, genus Paspalum. About 320 paspalum species are recognized, and most are native to the tropical and subtropical Americas. Certain paspalum species have become utilized as turf grasses, some are used as ground cover in areas of high salinity, and some are grown as livestock forage. So, is the paspalum beside the red cabin one of those? The way to know was to "do the botany" to get a name, then "look it up."

Another field mark for paspalum grasses is that their individual flowers, or spikelets, arise on short, slender pedicels from just one side of a long, ribbon-like "rachis," as shown at http://www.backyardnature.net/n/13/130707pr.jpg.

In that picture the items looking like black butterflies dangling on slender, white threads are pollen-producing anthers, and the fuzzy, black items issuing from the tops of florets are pollen-catching stigmas. Notice the very long, white hairs arising along the florets' sides. Such long, cobwebby hairs are so unusual that they constitute an important field mark for this species.

You can see how the florets arrange themselves beneath the ribbonlike rachis at http://www.backyardnature.net/n/13/130707pq.jpg.

When "doing the botany" on a grass, it's always a good idea to check out the "ligule," which is an interesting feature arising at the very base of a blade of grass where it makes contact with the stem. You can see this grass's ligule at http://www.backyardnature.net/n/13/130707ps.jpg.

Some grass species have ligules formed only of various kinds of hairs, others have papery ears, sometimes the ears are toothed, or tattered, or without features, and sometimes there are no ligules at all. Our paspalum's ligules are a little unusual in that they consist of both long hairs and papery ears.

Especially because of the long hairs arising along the florets' sides, our cabin-side paspalum keys out very quickly to PASPALUM DILATATUM, mostly known as Dallisgrass in English. At first I thought the name was referring to Dallas, Texas, but in fact the name honors A.T. Dallis, who imported the species into the US from its homeland in Uruguay and Argentina, promoting it as a fast growing forage plant able to thrive in the hot, humid US southern states.

As it turned out, the grass grew too well, and now has become a weed, especially antagonizing those who think that monocultured, crewcut lawns are desirable. Dallisgrass is shaggier than what lawn owners like to see. It's a perennial that grows in ever enlarging circular clumps, sometimes becoming so large that the clump centers die out while the outer rings continue smothering all turf grasses they overgrow. Dallisgrass's short rhizomes root easily in moist soil, making it difficult to control. In our area I suspect that the species enjoys a better reputation than farther east, since ranchers like just about anything that will grow in this arid land and which their cattle like to eat.

Paspalums in general produce grains cherished by many small, seed-eating birds.

*****

FLOWERING CALADIUM
Back in Kentucky caladiums used to grow around my mother's house, and that was very nice. I don't recall those caladiums flowering, however, while here in southwest Texas my neighbor Phred's plants are very floriferous, as you can see at http://www.backyardnature.net/n/13/130707cl.jpg.

In Mexico we saw many plants with flower structures like the pale ones in that photo's upper left, for the plant family to which caladiums belong -- the Arum or Jack-in-the-pulpit Family, the Araceae -- is a large, important one in the moist tropics, and the structure shown in the above picture is very typical of that family. A close-up is shown at http://www.backyardnature.net/n/13/130707cm.jpg.

In that picture we see many flowers. The banana-like item standing vertically and partly enveloped by the whitish hood is the "spadix," the Jack part of Jack-in-the-pulpit. The whitish hood, or "spathe," is the pulpit part. The spadix's grainy surface is formed by the flat tops of many closely packed anthers -- the pollen-producing, baglike tips of stamens of male flowers. Notice that below the white part of the spathe the spathe turns reddish and its edges curve, overlap one another, and the spathe bulges outward. If you force the bulging part open you'll find the base of the spadix clothed with numerous female flowers. Often in the Arum Family, once the female flowers are pollinated, the top male part of the spadix and the top, flaring part of the spathe wither away while the bulging lower part of the spathe expands and becomes a container protecting the lower part of the spadix on which ovaries of female flowers mature into fruits.

A garden columnist here in Texas advises snipping off caladium flowering structures because once the female flowers are pollinated the fruiting structures aren't pretty. I find them so interesting that I'd never do that. I don't see that their presence does any harm to the plant.

Of course I wondered what kind of caladium appears in my pictures. What I figured out was that the world of caladiums is enormous. Our plant is probably one of over a thousand named cultivars of the species CALADIUM BICOLOR, originally from Brazil and other parts of tropical America. You might enjoy browsing some of the hundreds of cultivars shown at http://www.classiccaladiumsllc.com/varieties/varieties.htm.

Besides all those cultivars of the species bicolor, several other caladium species are known as well, and certain cultivars on the market carry genes from those other species. Sometimes the genetic history of certain cultivars is so complex that they are referred to as Caladium x hortulanum, the "x" indicating that the plant is a hybrid, and the hortulanum meaning that it's a horticultural creation.

As with many members of the Arum Family, all parts of caladium are poisonous, containing calcium oxalate crystals and the protein asparagine. Fortunately, having calcium oxalate crystals in the mouth is so painful that I doubt any creature, including a human, would eat enough to die. I know what pain these crystals produce because when I was a teenager I bit into a raw Jack-in-the-pulpit corm.

Of course it makes sense for members of this family to be so well armed with hurtful chemicals. Usually their leaves are so large and succulent that any herbivore not knowing about the calcium oxalate crystals would want to eat them. The first mouthful, however, should convince the herbivore henceforward to stay away.

*****

LANTANA
Two weeks ago in our June 23rd Newsletter we looked at a bush growing in the wild here, known as the Texas Lantana. It was the native Lantana urticoides, so pretty that sometimes it's planted as a garden ornamental. You can see the Texas Lantana at http://www.backyardnature.net/n/w/lantana.htm.

In that Newsletter we mentioned that there's a very similar, much more widely planted and often escaped species, usually known simply as Lantana or maybe Shrub Verbena. That species, LANTANA CAMARA, is now flowering beside the red cabin in the valley. You can see a sprig of the very bushy, chest-high, woody shrub at http://www.backyardnature.net/n/13/130707la.jpg.

Flowers in that picture display very different colors from the more orange and yellow Texas Lantana in our first picture, so you might wonder why I keep saying that they're so similar and hard to distinguish. The reason is that in both species the flowers change color as they age, plus cultivars have been developed from each species displaying flower-color variations that may overlap between the two species. With other plants nearly always we say that to distinguish look-alike, closely related species it's necessary to see details of flower and/or fruit, but here is one instance when leaves provide the best field marks.

In Shinners & Mahler's Flora of North Central Texas I read that the Texas Lantanas' leaves normally bear a few teeth 2-5mm high, while our present Lantana camera leaves have leaf margins with more numerous teeth that are only 0.5-1.5mm high. Our plant's margins bear teeth about one mm high, as is proper for Lantana camara. If you flip between the above two links you'll start to see the difference.

Lantana camara -- the one beside the cabin in the valley -- is native to Mexico, some of the Caribbean area and parts of South America, plus across the US southernmost states it's escaped into the wild. In Florida it's become a serious weed in citrus groves. I've not found it growing wild here, though. It's also established as a weed across the world in warmer countries.

Though eating numerous green berries of Lantana camara can be fatal, and skin contact with the leaves can cause dermatitis in some people, the plant also can be very useful. Its stalks can be used as fiber for making paper. Traditionally, Lantana camara leaves have been boiled and applied to body swellings and painful spots. Lantana alkaloids have been found to stimulate intestinal movements in experimental animals, and to lower blood pressure.

Having digested all that, you might enjoy simply feasting your eyes on a Lantana camara flower head glowing in morning sunlight, shown at http://www.backyardnature.net/n/13/130707lb.jpg.

*****

FEATURED ESSAYS FROM THE PAST:

"Buddha in Xcalacoop," from the March 20, 2011 Newsletter, at http://www.backyardnature.net/n/p/110320.htm

"Buddha's Cloud" from the March 13, 2011 Newsletter, at http://www.backyardnature.net/n/p/110313.htm

*****

Best wishes to all Newsletter readers,

Jim

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