September 9, 2012
THIRSTY FOX SQUIRREL
Maybe a hundred yards (meters) behind the cabin, clear water runs about ankle deep across the Dry Frio River's flat, limestone bed. I was sitting on a little island of cobblestones in midstream when a large, rusty-tinged squirrel came sneaking through the streamside bushes, keeping to the shadows and being careful. Stealthily he moved behind a big sycamore with roots plunging directly into the water. After awhile the squirrel peeked from behind the tree, then moved around to the water side, and did what you see at http://www.backyardnature.net/n/12/120909sm.jpg.
After a good slurp the squirrel scampered up the sycamore and when he reached a dead snag high enough to feel safe he paused and looked around, as you can see at http://www.backyardnature.net/n/12/120909sl.jpg.
The large size and all that rustiness on the underparts -- in the tail and on the ears and eyes -- mark this as an Eastern Fox Squirrel, SCIURUS NIGER, not the usual gray squirrel of eastern parks and woodlots. Eastern Gray Squirrels don't naturally occur this far west, though they've been introduced here and there far beyond their native range. We are well within the Eastern Fox Squirrel's natural distribution, however, which is practically all of the eastern half of the US except for New England, most of New York, Pennsylvania and New Jersey. In our area they extend across the Rio Grande into Mexico, but just barely. However, they also have been introduced far beyond their natural range so you can't depend on distribution maps for identification purposes.
I've seen several fox squirrels here, and well I should, since Texas Live Oaks with their large acorns are abundant.
Behind the cabin in the Dry Frio River's streambed there's a certain place where sometime in the past floodwater deposited a bar of rounded, cherty pebbles and cobbles. Now water disappears into it and filters to the other side. As I approached a calm, algae-scummed pool where water disappeared into the sediment numerous tiny, gray critters I assumed to be grasshopper nymphs hopped out of my way like gray popcorn jumping from the streambed. But when finally I got a closer look, the popcorn turned out to be frogs, lots of them, tinier than you think a frog ought to be. You can see one, about an inch long (2.5cm) at http://www.backyardnature.net/n/12/120909fg.jpg.
With such warty skin at first I thought it was a baby toad, but atop the head behind the eyes there's no hint of a toad's bumpy parotoid glands and cranial crests. Often tiny frogs turn out to be treefrogs, but treefrogs normally have rounded pads on their toes, and this frog's toes don't have pads. Cricket frogs are tiny, but the cricket frogs I know are darker with conspicuous dark bands on the legs, and are often greenish.
So, referring to distribution maps in my Audubon field guide to reptiles and amphibians, I made a list of the eleven or twelve frog species possibly found in this part of arid southwestern Texas. Then through the process of elimination I came to this verdict: Blanchard's Cricket Frog, which is a subspecies of the Northern Cricket Frog. It's ACRIS CREPITANS ssp. BLANCHARDI. Apparently our southwestern Texas race is much paler than more northern individuals of the same species. Certainly here their color camouflages them well against the Dry Frio's white limestone streambed. Back in Mississippi we met another subspecies of Acris crepitans, subspecies crepitans, which is just called the Northern Cricket Frog. That one was much darker, as you can see at http://www.backyardnature.net/n/a/crikfrog.htm.
There's another cricket frog species I thought it might be, the Southern Cricket Frog, Acris gryllus, but it extends no farther west than Louisiana. Our Northern Cricket Frog species is found from just west of here, a bit across the border in Mexico, to Michigan and southern New York. I read that the Northern Cricket Frog is one of North America's two smallest vertebrates.
Cricket frogs are members of the Treefrog Family, so my opinion that treefrogs should bear round pads on their toes wasn't exactly right. Cricket frogs can be thought of as less tree-oriented but more aquatic treefrogs who don't need the adhesive toe pads in their watery habitats. Though we have plenty of them here, Blanchard's Cricket Frogs are listed as endangered in Wisconsin and threatened in Michigan, where since the late 1970s there's been a significant population decline because of habitat loss and chemical contamination.
Cricket frogs get their name from the clicking, metallic, crickety sound the calling males make at breeding time.
Wade across the Dry Frio River's ankle-deep waters just behind the cabin, climb the opposite slope, and instead of finding ranches or thickets of Ashe Junipers and Live Oaks as on this side, you see what's at http://www.backyardnature.net/n/12/120909sw.jpg.
Those flower stalks stand about ten feet tall (3m), so these plants provide an imposing presence, and when there are acres of them it's a marvelous thing to walk among them. This community grows where it does because in the past the flooding Dry Frio has left a terrace of cobblestones and gravel, and not much soil, several acres large. Rainwater soaks right through such unconsolidated debris fields, so only plants highly adapted to drought conditions can survive here. In fact these are very tough plants, as indicated by the hooked spines and tough fibers in a leaf section at http://www.backyardnature.net/n/12/120909sx.jpg.
You can see how the leaves arise from a basal stalk at http://www.backyardnature.net/n/12/120909st.jpg.
This plant is not an agave, though the Flora of North America assigns it to the Agave Family. It's the Texas Sotol, DASYLIRION TEXANUM, a species endemic just to southwestern Texas, here along the southern border of the Edwards Plateau, and a bit into adjacent northern Mexico. When I did my Spring Comes to the Desert book (which can be downloaded for free at http://www.backyardnature.net/j/books/index.htm#desert) I got to know Sotol, but that was a different species. In fact, 17 sotol species are recognized, and on the whole Earth sotols occur naturally only in Mexico and the US Desert Southwest. Here we have one of only three sotol species that extend into the US.
Like the agaves, sotols live for several years as a rosette of leaves, then they blossom and set fruit, and promptly die.
If you are familiar with the agaves' boxy, capsular fruits, you'll be interested to see how different sotol fruits are -- almost like those of the roadside weed called Curly Dock -- at http://www.backyardnature.net/n/12/120909sv.jpg.
The various sotol species have been important to people for a long time. First of all, the tough fibers in their leaves can be teased out and used for weaving and sewing. Indigenous Americans produced sandals, baskets, ropes, mats, and many other items with sotol fiber. Archeologists have dated artifacts made of sotol to as far back as 7000 BCE. You can see fibers curling from the disintegrating tip of a sotol leaf at http://www.backyardnature.net/n/12/120909su.jpg.
Also, like many agaves, the sotols produce a juice that can be fermented into an alcoholic drink usually called sotol. Still much drunk in Mexico, it's the "state drink" of the northern Mexican states of Chihuahua, Durango and Coahuila. Troughs cut into stone, with discarded sotol remains nearby, are assumed to be where ancient people produced the sotol drink as far back as 9000 years ago.
Pull an entire sotol leaf from the plant and its base can be cooked and eaten like an artichoke leaf -- by scraping nourishment from the base between the front teeth.
Field marks distinguishing our Texas Sotol from other US sotols include the leaves' greenness as opposed to other species' grayish sheen, and the leaves being particularly slender -- only up to ¾ inch wide (2cm).
Some folks in this area proudly display Texas Sotol plants in their front yards. Sotol is simply a wonderful plant, and I expect that I'll be wading across the Dry Frio many times just for the pleasure of walking among them.
On a rocky ledge over the Dry Frio River right behind the cabin several pricklypear cacti are now adorned with egg-shaped, egg-sized fruits, or tunas, as shown at http://www.backyardnature.net/n/12/120909op.jpg.
In general, cactus taxonomy is a mess, maybe because few taxonomists want to work with such spiny, hard-to collect plants as cacti. In the Cactus Family, the Cactaceae, one of the biggest and most easy-to-recognize kinds of cactus is the pricklypear group, genus Opuntia. The cactus in our picture is a pricklypear, a fairly representative one with its beavertail-shaped pads (modified stem segments) arising from one another. But which of the 34 or so North American pricklypear species is it?
Important field marks to notice for this species include that the plant is sprawling instead of rising on a sturdy trunk, and that the pads are fairly large and broad, sometimes almost circular. The pads are dull green, not a lustrous, deep green. The groups of spines are relatively widely spaced across the pads' faces, and the spines themselves are pale yellowish, not grayish, and tend to point downwards. Other important field marks are shown in a close-up of one of the little bumps, or areoles, from which spines, leaves and other structures arise at http://www.backyardnature.net/n/12/120909oq.jpg.
There you see that the large spines are flattish at their bases, and only slightly reddish instead of dark red. The numerous small spines at the base, called glochids, cluster on one side of the areole and, for glochids, are unusually large. These are important matters in pricklypear identification!
Keying our cactus out in the online Flora of North America leads to the name OPUNTIA ENGELMANNII var. LINDHEIMERI, often known as the Texas Pricklypear. This variety, lindheimeri, is typical of the Chihuahuan Desert of northern Mexico and southern Texas. The broader species is found from southern California north to Utah, east through southern Texas, and south through much of arid northern Mexico. Also, the broader Opuntia engelmannii is one of the most taxonomically difficult and tossed-about of all pricklypear species. Each of my three cactus field guides uses a different binomial name for it.
Del Weniger, author of Cacti of Texas and Neighboring States -- a book that delighted me while backpacking in Big Bend National Park a few years ago -- is a real cactus lover, yet on his page for the Texas Pricklypear uncharitably he refers to this lindheimerii variety of Opuntia engelmannii as the "worst pest pear of south Texas." I personally have always been pleased to meet it, however, and find nothing pestiferous about it. I think he is trying to say that the species is uncommonly flexible in its habitat requirements, and is capable of surviving in many places humans disturb.
Nowadays in this part of the country one of the most conspicuously flowering and common wildflowers is the waist-tall, much branching member of the Composite or Sunflower Family with alternating, silvery-green-leaves and yellow blossoms shown at http://www.backyardnature.net/n/12/120909vb.jpg.
This pretty herbaceous plant grows all along rocky limestone cliffs hemming in the Dry Frio River, along roadsides, and as a display plant in my host's wildflower garden. Before I came here my host tested me by sending a picture of the plant. Knowing that the Flora of North America treats 2413 species of the Composite Family, and seeing that the picture didn't show most of the features used when differentiating the 2413 species, I had no idea what it was, and just told my host that it was one of many members of the Sunflower Family. This did not help my credibility as a naturalist, since my host knew it was common as sin and that everyone and his brother called it Cowpen Daisy.
This week I "did the botany" on the Cowpen Daisy. A close-up of a single head, with numerous disk flowers in the center surrounded by many ray flowers, each ray corolla deeply incised with three teeth at their tips is shown at http://www.backyardnature.net/n/12/120909vc.jpg.
Overlapping, sharp-pointed bracts beneath the head are invested with a wool of silvery hairs as shown at http://www.backyardnature.net/n/12/120909ve.jpg.
At http://www.backyardnature.net/n/12/120909vd.jpg, at the bottom, you see a disk flower, the white base of which is the future dry, one-seeded fruit, or achene, atop which arise several short, sharp scales and two or three short, slender hairs. The ray flower at the top lacks the white achene because it is sterile. You can see some mature achenes with their distinctive "wings" of stiff, tawny hairs at http://www.backyardnature.net/n/12/120909vf.jpg.
So, all this and more means that here we have VERBESINA ENCELIOIDES, which my Peterson field guide to the wildflowers of the Southwest and Texas names Golden Crownbeard. Other sources call it Butter Daisy, American Dogweed, South African Daisy, Wild Sunflower. Girasolcito, Yellowtop, Anil del Muerto and, even Cowpen Daisy. That's what I'll call it, since people around here know it only by that name.
Cowpen Daisies are tough, aggressive plants that can invade disturbed habitats as "weeds." As such they are so generally distributed that the experts can't say exactly where their homeland is, other than somewhere in the relatively hot, dry areas of the Americas. In the US it turns up in most of the south and central states, plus Mexico, the Caribbean, and South America, plus it's been introduced into Asia, Australia and Hawaii.
On Midway Island introduced Cowpen Daisies threaten all ground-nesting birds, especially rare Laysan Albatrosses, because the plants grow up rapidly around nests preventing parent birds from feeding their chicks. The chicks become trapped and are unable to reach the ocean at fledging, and die of starvation. The plants also shelter aphids, scale insects, and the ants that tend them, the ants then preying on the eggs and chicks of ground-nesting birds. Here in its native land the Cowpen Daisy has evolved in a cooperative way with its surrounding community of plants and animals, and doesn't create such problems. But where it's introduced as an invasive, it can be very destructive and undesirable.
Though accounts mention Cowpen Daisies being used to treat skin ailments of early settlers and indigenous Americans, the plants aren't known as being particularly medicinal. They contain the compound galegine, which can be lethal in large enough amounts, though. The flowers seem to be an exceptional source of nectar for pollinators, and they are so downright pretty, however, that here in their native land you just have to appreciate them.
A fairly common weed along roads and in miscellaneous abused soils nowadays is the one flowering at http://www.backyardnature.net/n/12/120909mu.jpg.
As a kid this was one of the first two or three plants I learned the name of from a book, because it was so distinctive with its rosette of large, soft-fuzzy leaves topped with a spike of yellow blossoms that even with the simple black-ink drawings in my old wildflower book I could be sure of what I was seeing. There's just nothing else that looks like it. Common Mullein, the book said, VERBASCUM THAPSUS. "The ancient Romans dipped Mullein stem heads in tallow, set them ablaze, and used them as torches in funeral processions," I read. To this day I can't see a Mullein without visualizing weeping Romans in white togas bearing a casket through dark streets.
I'm used to Mullein flowering earlier in the year, in June or so, so maybe our flowering ones are reacting to an unusual downpour occurring here a few weeks back. Other Mulleins in the area already have their tall, dark spikes of seed-dropping capsules, as shown at http://www.backyardnature.net/n/12/120909mx.jpg.
That picture shows something important about Mulleins. That is, Mulleins are biennials. During their first year of growth they produce only rosettes of leaves, like the plants in the front of the picture. Then in the second year the flowering spike "bolts" higher and faster than any mere annual plant could manage, taking advantage of energy in carbohydrate stored during its first year of life. This is an important adaptation, since the species doesn't compete well with other plants, being intolerant of shade and disturbances such as tilling. Another adaptation compensating for these deficiencies is that the seeds remain viable for decades -- even a hundred years or so according to some studies -- so they can wait in the soil until conditions are just right for them. They germinate only on bare soil, or after a fire.
Mullein's flowers bear five lobes, or petals, and are slightly asymmetrical -- they're bilaterally symmetrical instead of radially symmetrical. A flower close-up shows this, as well as the five stamens -- three smaller, very hairy upper ones and two larger, hairless ones below -- at http://www.backyardnature.net/n/12/120909mv.jpg.
Mullein is native to Europe, northern Africa and Asia, but was introduced here early. The Puritans brought mullein seeds to America for their medicinal herb gardens. From ancient times in Europe a tea was made from its leaves as a cure for lung diseases in both humans and livestock. It's been used against diarrhea and rheumatism, and ointments have been made of it for burns and earaches. Sometimes its dried leaves have been smoked as a tobacco substitute.
With such a long, colorful history, the plant has acquired many names other than Mullein. There's Hedge-taper, Candlewick, Lungwort, Feltwort, Hare's-beard, Torches, Blanketleaf; Jacob's-, Jupiter's-, and Peter's-staff, Shepherd's Club, Aaron's Rod, Velvetplant, Old Man's Flannel, Miner's Candle, and others.
The names referring to felt, blankets and velvet comment on the pleasantly soft and fuzzy felt covering the leaves. A close-up showing how the long hairs branch and mat together is at http://www.backyardnature.net/n/12/120909mw.jpg.
PAMPAS GRASS ON THE DRY FRIO
Just below the cabin on a little gravel island barely rising above the Dry Frio River's ankle-deep water grows the eight-ft-tall (2.5m) grass shown at http://www.backyardnature.net/n/12/120909gr.jpg.
Anyone familiar with popular landscaping plants will recognize this as Pampas Grass, CORTADERIA SELLOANA, but most of us never see Pampas Grass growing in the wild, unless we visit its homeland in South America. The Pampas Grass in the picture surely got established when the wind carried a tiny, white-parachuted fruit from my neighbor's much taller and more robust plants exactly in front of the cabin's driveway, shown at http://www.backyardnature.net/n/12/120909gq.jpg.
In Argentina and southern Brazil Pampas Grass grows naturally along streams and other low, wet areas, so here along the Dry Frio a wayfaring fruit has managed to find just what it needs.
A close-up some Pampas Grass spikelets is shown at http://www.backyardnature.net/n/12/120909gs.jpg.
A feature separating Pampas Grass spikelets from those of, say, the bluegrasses or fescues, is their very long pairs of glumes -- glumes being the silvery, long-pointed items at the base of each spikelet. The glumes are much longer than the collection of florets themselves, which is a little unusual. These special grass terms are explained on our grass page at http://www.backyardnature.net/fl_grass.htm.
Pampas Grass produces unisexual flowers, usually on different plants but sometimes flowers of both sexes occur on the same plant. It's easy to know that the flowers in the picture are female, because Pampas Grass's male flowers lack the long hairs that give these flowers a fuzzy appearance.
Pampas Grass has been reported as an invasive growing wild at several locations in Texas, but the species doesn't seem to be populating large areas like some weedy species.
SLENDER ORANGE BUSH LICHEN
On gnarly oak branches often you see the orange fruticose lichen shown at http://www.backyardnature.net/n/12/120909li.jpg.
Having no idea about its identity I did an image search on the keywords "lichen orange tree branches Texas" and that brought up pictures that gave me the name: TELOSCHISTES EXILIS, sometimes called Slender Orange Bush Lichen. It occurs in tropical and subtropical habitats throughout the Americas.
Whenever you see a brightly colored lichen like this one, there's a good bet you can extract dye from it. However, you don't necessarily get the color you're expecting. One study found that using an ammonia extraction method Slender Orange Bush Lichen produced a pink dye that turned slate blue in sunlight. If you extract several times with ammonia you get brown or rose on the first steeping, deep rose on the second steeping, and pink on the third steeping. That study can be accessed at http://www.turkeyredjournal.com/Dean.html.
Several web pages remark that Slender Orange Bush Lichen is disappearing in their area, which suggests that the species is vulnerable to pollution. Happily, the air in our isolated little corner of southwest Texas seems to be very clean.
However, some people here spray their trees to kill the lichens and bromeliads on them. They observe that lichens and bromeliads occur on dead branches, so they reason that the lichens and bromeliads must be killing those branches. Of course it's the other way around: The dead branches offer living space in good light, so lichens and bromeliads cluster there, not on the living branches where leaves produce too much shade for them. Moreover, studies on the matter show that lichens and bromeliads produce nutrients valuable to their host tree. People should be happy to have lichens and bromeliads on their trees, and not spray to kill them.
FEATURED ESSAYS FROM THE PAST:
"Presence & Position," from the August 15, 2010 Newsletter, at http://www.backyardnature.net/n/p/100815.htm.
"Philosophizing Like Grandma Moses," from the October 23, 2011 Newsletter, at http://www.backyardnature.net/n/p/111023.htm.
Best wishes to all Newsletter readers,
All previous Newsletters are archived at http://www.backyardnature.net/n/.
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