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

December 30, 2012

SYCAMORE TWIGS
Down on the little floodplain of the Dry Frio River behind the cabin there are lots of Sycamores. On cobblestone bars where flashfloods rampage from higher up the Edwards Plateau maybe once or twice a year the trees are young, or at least young sprouts on long-established but much battered roots, for once a tree gets very large and stiff, a flood shatters it. I'm told that when the river is in flood you hear large boulders knocked about in the waters, so large trees there don't stand much of a chance.

Nowadays some of these Sycamores are completely leafless while others retain quite a few leaves that are so brown and crisp that you wonder why a tree would keep them.

Some Sycamores that have lost all their leaves nevertheless are not entirely naked, for at each of their stem nodes where earlier a leaf had been attached now there's not only the usual bud containing embryonic tissue for next year's leaves and stems, but also a stipule. And few trees produce such large, leafy stipules as the Sycamore. You can see a typical Sycamore stipule with its attending bud at http://www.backyardnature.net/n/12/121230sy.jpg.

In that picture the stipule is the flaring, brown, leafy item occupying most of the top, right of the picture. Notice that its base encircles the stem, and that the base has come loose, leaving a barely visible ring around the stem, which is the stipular ring, or scar. Stipule scars on twigs of most tree species are small, not encircling the stems, or nonexistent, so the Sycamore's stipular rings make a good field mark if you're out identifying trees from their winter twigs.

At http://www.backyardnature.net/n/12/121230sz.jpg you see another Sycamore twig with a stipular ring encircling the stem at the base of the bud, but on this twig the stipule has fallen away. Also, something strange is going on in the picture's top, right corner.

In that picture the shriveling item exiting the top, right corner is the stem, or petiole, of a dried-up Sycamore leaf about to fall off. In fact, the petiole base has come loose from the stem so that a little of the twig's greenish-yellow terminal bud peeps through. Here you can see that the leaf's petiole base covers the bud like a cap, and that's another curious field mark for the Sycamore.

As a Sycamore's stipules leave stipular rings encircling the stem, when a Sycamore sheds a leaf, the leaf petiole leaves a narrow leaf scar practically encircling the conical bud, as you can see at http://www.backyardnature.net/n/12/121230sx.jpg.

In that picture the bud-encircling leaf scar is like a shallow, narrow mote around the bud. Notice also that this Sycamore bud is covered with only one or two bud scales, which is very different from, say, an oak bud with its several scales, or a Magnolia bud with no scales at all.

So, all this goes to show that the Eastern Sycamore's winter twigs are very distinctive. In a way, however, that's sort of a waste of good field marks, since the Sycamore already is such a unique tree that almost everyone can identify it on sight. For, it has a white, blotchy bark unlike almost any tree, plus of all North American trees the Eastern Sycamore is one of the tallest, at around 165 feet (+50m) and with the greatest trunk diameter, reaching over 13 feet (+4m) across.

*****

FOXTAIL ALONG THE RIVER
Nowadays much of the landscape is the color of winter, dun colored, a subdued but pretty hue especially where there are broad expanses of prairie grass. We do have plenty of greenness here to look at, though, because our two dominant trees, Ashe Junipers and Texas Liveoaks, green the hillsides. Though the vast majority of our grasses are dun colored, along the banks of the little Dry Frio River behind the cabin there's one grass species with stiff, green leaves bucking the trend, obviously a perennial, and you can see it at http://www.backyardnature.net/n/12/121230fx.jpg.

With those fuzzy heads atop long stems held above the knee-high clump of blades they couldn't be anything but what's generally called foxtail grass or bristlegrass, genus Setaria. However, the foxtail species I'm most familiar with are herbaceous and now are winter-colored. Who is this foxtail that stays green into the winter?

The most obvious field mark distinguishing this foxtail species from the other 32 or so Setaria species found in the US -- of which about a third are invasive non-natives -- is that it is a perennial. However, several other foxtail species also are perennial.

Most of the heads visible in the photograph have already shed their achene-type fruits, but down among the blade bases there was a head with flowers. You can see the feathery, pollen-collecting stigmas atop those flowers at http://www.backyardnature.net/n/12/121230fz.jpg.

That picture shows that several bristles arise below each oval spikelet, not just three or fewer, which is the case with some species. Also, if you look closely you can see that the bristles bear very tiny barbs pointed outward, toward the bristle's tip. The bristles of some species point downwards, or backwards. Also, the green spikelets are smaller than those of a lot of species, only about 2.5mm long, or 3/32nds of an inch. Comparing them with the ridges in the palm of my hand you can see how tiny the mature grains are at http://www.backyardnature.net/n/12/121230fy.jpg.

This species keys out as SETARIA PARVIFLORA, the species name parviflora meaning "small flowered." The species is native to the Americas, but now is established as an invasive weed in much of the world, so it known by several English names, including Marsh Bristlegrass, Bristly Foxtail, Knotroot Bristlegrass, and Yellow Bristlegrass. The species is regarded as the most morphologically diverse and widely distributed of all native North American foxtail species.

The small grains dropped by all the foxtail species are favored by birds who forage on the ground, especially sparrows.

*****

LIP FERN
In thin, very dry soil between limestone rocks atop a nearby hill there's a dignified, even stately little six-inch tall (15cm) fern that at first you don't see because it's so small and densely invested with silvery hairs that the fronds are whitish, thus well camouflaged among the white limestone rocks and winter's crisp, sunlight-reflecting leaves. Only when you get up close and pay attention do you see its charm, as shown at http://www.backyardnature.net/n/12/121230ch.jpg.

If you examine with a magnifying lens this fern's frond segments, or pinnae, you see that their top surfaces are covered with very unusual white, triangular scales fringed with hairlike teeth, as shown at http://www.backyardnature.net/n/12/121230ci.jpg.

Bottoms of the pinnae are even more thickly mantled with white scales, as shown at http://www.backyardnature.net/n/12/121230cj.jpg.

When you find a fern that's new to you like this, you need to look for clusters of spore producing sporangia -- on frond bottoms the clusters often are called sori, or fruitdots -- because sporangia clusters come in all kinds of configurations, and the configurations vary from species to species, so they make good field marks to help in identification. At first I thought the fronds in the picture were all sterile, but when I looked very closely with lens I saw sporangia, as you can see at http://www.backyardnature.net/n/12/121230ck.jpg.

The sporangia are those reddish-brown, snail-like items almost hidden among the deeply fringed scales on a pinna's undersurface. The seemingly segmented ridges running across the spherical sporangias' tops are special structures helping with spore dispersal. They're called annuluses. When spores inside a sporangium are mature, water inside its annulus's cells or segments drains out causing tension along the annulus's length itself, and across the surface of the sporangium to which it is attached. Eventually the baglike covering of the sporangium snaps open, scattering spores. In this species, each sporangium holds 32 spores. An unusual feature of this species is that its sporangia are not neatly clustered in distinctive fruit-dots on the undersurfaces of the pinnae or inside curled-under pinna-edge margins, but rather haphazardly along the pinnae margins.

This interesting fern is a member of the genus Cheilanthes, a group of ferns commonly known as lip ferns. It's CHEILANTHES EATONII, sometimes referred to as Eaton's Lip Fern. It occurs widely on rocky slopes and ledges, mostly on limestone and granite, in much of Mexico, in Costa Rica, and in the US from Arizona to Colorado and south to here, and sporadically to Virginia.

The fern's coating of white scales protects its fronds from extremes of sunlight, wind and temperature atop the hill, and reduces evaporation of precious water during long periods of drought. When the fern gets very dry, its pinnae ball up, thus offering less surface area vulnerable to evaporation, as shown at http://www.backyardnature.net/n/12/121230cl.jpg.

*****

JAPANESE RADISH/ DAIKON
When I arrived here in late August I wanted to plant a winter garden but I'd brought only turnip and mustard greens seeds from Mississippi. My host had a package of seeds of Japanese Radish, which I'd never grown or eaten, but I planted them just to see what would happen.

The plants thrived, producing lovely dark green, pinnate leaves, and after a few weeks a white little taproot developed beneath the leaves and that was the future radish. These were tough plants, not wilting when southwestern Texas's hot, dry September winds blew, and they didn't develop the leaf diseases that some other crops did. I don't particularly like the taste of radishes but when I needed the raised bed for planting another crop I do like, those Japanese Radish plants looked so healthy and promising that I couldn't bear the thought of uprooting them.

For the last month or so the Japanese Radishes have been at the peak of perfection. You can see one plucked from the soil this Wednesday at http://www.backyardnature.net/n/12/121230jr.jpg.

Japanese Radish plants look much different from radish plants producing those small, spherical, red-top-and-white-bottomed, peppery tasting radishes most Americans think of as a radish. Not only is the taproot radically different but also the leaves. Leaves on "regular" radish plants are much shorter and bear only one to three pairs of leaf lobes, while Japanese Radish leaves produce eight to twelve pairs.

These conspicuous differences between "regular" radish plants and Japanese Radish plants make it a little surprising to learn that both radish types are the same species -- they're RAPHANUS SATIVUS -- just different varieties. Japanese Radish is Raphanus sativus var. longipinnatus. Some authorities refer to radishes of this variety as Chinese Radish, which might be more appropriate, since the cultivar originated in continental Asia and was introduced into Japan via China during the Han Dynasty, around 2000 years ago. I call it Japanese Radish only because that's what the seed package said, and it seems that that name is most used in the US. In the UK they may call it Mooli, and in the literature often it's referred to as Daikon, from the Japanese meaning "big root."

Japanese Radish taproots aren't nearly as peppery tasting as regular radishes. Their leaves can be steamed and used as greens, but they're not as tasty and pleasingly textured as turnip and mustard-greens leaves. I personally like them best shredded into salads and used as a garnish. Mixed with avocado they're especially good. In Asia they're commonly used in soups, pickled and stir fried. A typical dish from Bangladesh mixes finely grated root with fresh chili, coriander, flaked steamed fish, lime juice and salt, then is served alongside meals.

For me, Japanese Radishes are worth growing mainly because they're such handsome, well behaved plants, just a pleasure to look at.

*****

DIGGING THROUGH THE CRETACEOUS
My house-painting job finished, now I'm digging trenches on the nearby rocky hillside. I like this work, at least for the couple of hours each day I do it.

Digging through the soil is easy, but the limestone rock and bedrock below the soil is a challenge. It's not as impossible as it sounds, though, because the limestone varies from crystalline, "rock hard" rock to fairly soft, crumbly stuff. You can see one of my trenches with dark soil above transitioning to soft, white limestone below at http://www.backyardnature.net/n/12/121230c2.jpg.

The hill's bedrock is mostly Cretaceous limestone, which means that it was deposited as sediment during the Cretaceous geological period between approximately 145.5 and 65.5 million years ago. During the Cretaceous the Earth's sea level was much higher than now. In North America we have extensive outcroppings of Cretaceous-age rocks because during the Cretaceous Period a great sea connected the Arctic Ocean with the Gulf of Mexico, running right through the middle of the continent. The mud in that great sea eventually lithified into limestone and was raised to form much of North America's current interior landscape.

In the above picture, I could dig through that limestone with a shovel. You can see a small rock shoveled from the trench at http://www.backyardnature.net/n/12/121230c3.jpg.

Since solid, crystalline limestone would break forming flat surfaces and sharp edges, you can tell from that rock's rounded, broken surfaces and the powder on my fingers that it is crumbly, porous and lightweight. While digging through it I asked myself if it might be impure chalk. After all, the word Cretaceous is derived from the Latin word for chalk, which is creta, because in many places across the globe besides North America there are many outcroppings of chalk. The "White Cliffs of Dover" in England are white because they are Cretaceous chalk. The Champagne region of France is mostly underlain by Cretaceous chalk into which artificial caves have been dug and used for wine storage. So, why couldn't I be digging through real chalk on our Texas hillside?

The USGS now provides a wonderful Internet page where for free you can access hundreds if not thousands of geological maps covering the entire United States. The page is at http://ngmdb.usgs.gov/maps/MapView/.

There the Geologic atlas of Texas, San Antonio sheet published in 1982 by VE Barnes et al by the University of Texas at Austin informs me that our hills here in northern Uvalde County along the Dry Frio River are capped with the geological unit known as the Edwards Limestone, but on the hills' lower slopes -- where I'm trenching -- the outcropping rocks belong to the Glen Rose Formation.

As with plants and animals, once you have the name of something, you can look it up. Looking up "Glen Rose Formation" on the Internet I find a fine website on Texas fossils with a whole page about the Glen Rose Formation and its fossils, at http://northtexasfossils.com/glenrose.htm.

There I learn that the Glen Rose Formation is composed of rocks from the early part of the Cretaceous Period -- that they're ±108 to ±113 million years old. Also I read that though the Glen Rose Formation is normally thought of as a limestone outcrop, it also contains strata of sandy mudstone, wackestones, calcarenites, marls, micritic limestones, dolomites, quartz siltstones, sandstones, and boundstones. I've never heard of a couple of these terms. Chalk isn't on the list.

Chalk is described as mainly soft, white, very fine-grained, extremely pure, organic limestone composed of shells of microscopic organisms. The rock I'm digging through is not pure and not very fine-grained, so it must not be chalk.

A friend tells me that I'm digging into calliche, which is a kind of rock-hard hardpan that forms in arid and semi-arid lands just below the soil. Calcium carbonate cements together gravel, sand, clay, and silt to form it. However, farther up the slope I'd first encountered the white layer shown in the picture immediately beneath a layer of hard, limestone bedrock, which disappeared as I worked down the slope, so what's in the picture is a Cretaceous-age stratum, not recently formed caliche.

In the list of Glen Rose rock-types, marl catches the eye. Marl is a calcium carbonate or lime-rich mud or mudstone which contains variable amounts of clays and silt. Some people say that "marl" is a too general and imprecise term and that rock called marl more correctly should be called earthy or impure argillaceous limestone. "Argillaceous" is a term describing rocks in which clay minerals are a secondary but significant component. "Clay minerals" are mostly silica based. They're hydrous aluminium phyllosilicates, sometimes with variable amounts of iron, magnesium, alkali metals, and other such non-organic compounds.

So, letting all that digest awhile, I figure that nowadays when I dig down through the soil, if I hit white, soft, impure not-quite-rock that's not caliche, I'm digging into "impure argillaceous limestone," and if I can't remember the word "argillaceous," I'll just call it marl.

*****

ORGANIC EAR CANDLES
Let's end this calendar year -- the natural year in the Northern Hemisphere ended with the Winter Solstice -- with something different.

For three months my Estonian lady friend Malle has been living with me, and I have enjoyed learning a bit about her culture, and even the Estonian language, which is closely related to Finnish. "Tere hommikust" I say each morning when I come in from jogging, for "Good morning."

The other day a package arrived from Estonia bearing Christmas gifts and a few items from the motherland Malle felt like she needed but couldn't get here. "Taimsed kõrvaküünlad" was printed across two interesting looking packages so I asked what that meant.

"Organic ear candles," Malle replied with glee, and one package was for me. You can see what the package looked like and what was inside at http://www.backyardnature.net/n/12/121230ea.jpg.

Ear candles are not part of Estonian culture, but rather of the Chinese, Indian and Tibetan cultures. Ear candles not only clean ears but have a spiritual action. "Alive fire cleans energies in the body and stimulates the spirit," Malle says.

Heat from the candles melts ear wax and air currents streaming up through the candles' empty interior carry wax with them. You swab out any wax remaining in the ear with a cotton swab. In the picture you see two candles. Malle says that they are made from cotton fiber soaked in beeswax, oil of eucalyptus and peppermint, and cinnamon, lavender, and other such ingredients. You can see what it looked like when Malle placed an organic candle in my ear and set it ablaze at http://www.backyardnature.net/n/12/121230eb.jpg.

I feared that sparks might fall down inside the straw into my ear but there were no sparks. You can see how the straw chars black and doesn't crumble. As the flame approaches the narrow blue ring around the candle's base you feel a little heat but not much. Mainly you hear the crackling flame approaching and that's why I look a little worried.

When the flame reached the narrow blue ring Malle removed the candle and doused it a glass of water she'd set beside us, and then she started unrolling the candle's base. You can see what she found inside the base at http://www.backyardnature.net/n/12/121230ec.jpg.

She says that the yellowish powder is tiny beads of wax that had melted in the ear, then was carried up into the candle to accumulate there.

I didn't experience much of a change in my ear, but Malle says you have to use ear candles regularly to get the full benefit.

*****

FEATURED ESSAYS FROM THE PAST:

"Campfires & The Middle Path," from the May 30, 2010 Newsletter, at http://www.backyardnature.net/n/p/100530.htm.

"Fine-tuning The Middle Path," from the August 15, 2004 Newsletter, at http://www.backyardnature.net/n/p/040815.htm.

*****

Best wishes to all Newsletter readers,

Jim

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

Visit Jim's backyard nature site at http://www.backyardnature.net