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 9, 2012

SHARP-SHINNED HAWK AT DUSK
As the dusk walk ended and the sky shed just enough light for things to appear as silhouettes, a small raptor glided fast onto a branch of a nearly leafless oak tree and looked around. The bird was so small that at first I thought he was a Kestrel, or Sparrow Hawk, but Kestrels have more rounded, thicker-necked bodies, plus, remembering how the hawk had glided in on rounded wings held straight out from his body, not with pointed, swooped-back wings like the Kestrel's, I figured it was our smallest accipiter-type hawk, the Sharp-shinned Hawk Accipiter striatus. You can see his silhouette, with a PhotoShop-overexposed image of the same silhouette at the right revealing the barred tail and streaked underparts of an immature bird, at http://www.backyardnature.net/n/12/121209ss.jpg.

My field guide gives the Sharp-shinned's length as 10┬Ż inches (27cm), which can be compared to the Red-tailed Hawk's length of 18 inches (46cm).

Sharp-shinned Hawks often show up at midday soaring over the valley's extensive pastures. Early and late in the day they tend to fly low over the trees hoping to surprise small to medium-sized birds, which it preys on.

*****

NERVOUS ROBINS
Occasionally you hear the unmistakable nasal calls and cluckings of American Robins. You can see a freshly molted one in a tree beside the cabin at http://www.backyardnature.net/n/12/121209ro.jpg.

This is interesting because during the hot breeding season robins don't occur in southern and most of western Texas. They nest in the southern half of Canada and the greater part of the US, but not here and nearly all of Florida. You can see their summer distribution map at http://www.mbr-pwrc.usgs.gov/bbs/htm96/map617/ra7610.html.

That map can be compared with their winter distribution map at http://www.mbr-pwrc.usgs.gov/bbs/cbcra/h7610ra.html.

The winter map shows that during the cold months American Robins are common in southern and western Texas as well as throughout most of the US, though they've mostly vacated Canada. Consequently, in most of the US you can see robins year round, but they're not the same birds. The whole population shifts southward, so the birds seen at my old hermiting spot in southern Mississippi may have spent their summer at my childhood home in Kentucky, or farther north.

Winter birds also behave differently, not hopping around on suburban lawns and defending their territories as in the summer, but rather they join in flocks that mostly stay in the countryside. These winter birds are relatively nervous and much less approachable. The one in the picture was constantly eyeing me and clucking his danger call. In the winter, American Robins are found throughout much of highland Mexico, too.

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MISTLETOE FRUITING
Since the vast majority of our trees are either Ashe Junipers or Texas Live Oaks and these species don't seem to be parasitized by mistletoe, mistletoe isn't as conspicuous in this area as in some. However, there's one occasionally occurring tree species in which most of the mature trees do bear bushel-basket-sized, compact, green clumps of mistletoe, and that's the Cedar Elms. Mistletoe in Cedar Elms is showing up nowadays because the trees have lost most of their leaves. You can see a typical clump in a Cedar Elm at http://www.backyardnature.net/n/12/121209mi.jpg.

A close-up of this misteletoe's pretty fruits is shown at http://www.backyardnature.net/n/12/121209mj.jpg.

The fleshy, berry-type fruits contain several seeds embedded in very sticky juice. The seeds are dispersed when birds eat the fruit, get seeds stuck to their bills, then fly away and wipe their bills on tree branches, effectively planting the seeds where they can germinate.

Around here people call our mistletoes Christmas Mistletoe. They're PHORADENDRON TOMENTOSUM, which is a different species from the ones commonly seen in eastern North America and along the Pacific coast. Phoradendron tomentosum is mainly distributed in arid northern Mexico, but extends into the US in Texas and parts of Oklahoma and Louisiana.

Phoradendron tomentosum has received attention lately because traditionally in arid northern Mexico it's been used to treat diabetes. In a paper appearing in Proceedings of the Western Pharmacology Society 45: 162-163 (2002) the Mexican researchers state that "... two diabetic patients commented to us that they have been drinking the aqueous extract of this medicinal plant for approximately one year (two glasses daily, 300 ml each) to treat their high levels of blood glucose. With this treatment, they decreased their blood glucose levels to near normal values, and discontinued their medical treatment with oral hypoglycemic agents."

For their research they studied the effects of this "mistletoe tea" on diabetic rats, and found that "... in 45 days the glucose levels of the diabetic animals decreased significantly relative to the diabetic control group, which was treated only with water."

This is pretty exciting information and one wonders why such a simple and inexpensive cure isn't being made available nowadays. You can download the paper for free in PDF format. Find the paper by doing a search on the paper's name, "Preliminary Chronic Toxicological Study of Aqueous Extract of Phoradendron tomentosum."

I'd be careful experimenting with mistletoe teas on my own, however, since the foliage and berries of some mistletoe species are toxic.

*****

PRICKLY SOW THISTLE FLOWERING
Just a month ago so many wildflowers and weeds were flowering that I thought that maybe all through winter we'd have at least a few flowering plants to look at, since we're so far south. However, despite our not yet having had a hard frost, suddenly there's very little blossoming now. One big exception -- and this because it's growing against the south-facing wall of the cabin where the temperature averages a lot warmer -- is the knee-high, annual or biennial herb shown at http://www.backyardnature.net/n/12/121209so.jpg.

That's the Prickly Sow Thistle, also called Spiny Leaf Sow Thistle, SONCHUS ASPER. This plant's spiny leaf margins help us identify it, as well as its composite-type flower heads, which look like small Dandelion heads, as shown at http://www.backyardnature.net/n/12/121209sp.jpg.

In that picture you see that this is one of that subgroup of Composite Family members, along with Dandelions, in which the flower heads are composed only of flat, petal-like "ray flowers." Most composite flower heads are a mixture of flat ray flowers and cylindrical disk flowers, and some, like the Eupatoriums, have only disk flowers. In the above picture, the head at the far left has flowered and the ray flowers are turning brown, while the urn-shaped collection of scales or bracts enveloping the flowers' bases -- the involucre -- protects the developing cypsela-type fruits. At the top of the picture another flower head is even more mature, the involucre about ready to open up and release the cypselae into the wind, the fruits being equipped with hair-parachutes, again like Dandelion fruits.

A longitudinal sections of a flower head showing white, developing fruits at the bottom of each flower, and white hairs that later will form the parachute that will carry the fruits on the wind, plus the ray flowers' yellow corollas and the wiry, curly style branches is at http://www.backyardnature.net/n/12/121209sq.jpg.

Our Prickly Sow Thistle is one of two similar sow thistle species -- members of the genus Sonchus -- commonly found growing weedily in all but northernmost North America. Both are invasive species from Europe, and both now have spread into weedy places pretty much worldwide. The other species, Sonchus oleraceous, often is called the Common Sow Thistle, though in our part of the world the Spiny Leaf Sow Thistle seems more common than the Common. The prickles on our Prickly Sow Thistle are so stiff and sharp that if you grasp a leaf it can hurt. The Common Sow Thistle's leaf spines aren't as stiff and hurtful. The other good field mark differentiating the two species is shown at http://www.backyardnature.net/n/12/121209sr.jpg.

Notice that where each leaf meets the stem the blade bottom enlarges and curls around into an ear-like lobe, or "auricle." Both of the common, weedy sow thistle species bear spiny-margined leaves with auricles, but our Prickly Sow Thistle's auricles are rounded, as shown, while the Common Sow Thistle's auricles are variously shaped, sometimes a bit triangular, but not consistently rounded.

Having such a lush bounty of Prickly Sow Thistles beside the cabin I couldn't resist picking a mess of young leaves and sprouts, and cooking them. The spines on young leaves, once they're cooked, aren't noticeable when you eat the leaves. The leaves cook down to a soft pulp like cooked spinach. Remembering that some potent alkaloids occur among the milkweeds, I threw away the water the greens were cooked in, though with turnip greens and the like I drink that water. Cooked sow thistle tastes good, wholesome, maybe like picked roadside dock.

I read that traditionally Prickly Sow Thistle has been pounded and applied as a poultice to wounds and boils. A research paper out of Pakistan asserts that Sonchus asper possesses antioxidant capacity and is used in liver and kidney disorders. It was found that a methanolic extract of Sonchus asper "ameliorated the oxidative damage and had increased the regenerative and reparative capacity of liver and kidneys." That paper is freely available at http://www.biomedcentral.com/1472-6882/11/113.

*****

TALAYOTE VINE FRUITING
Nowadays often you see suspended in trees green pods on drying-up vines such as those shown at http://www.backyardnature.net/n/12/121209cy.jpg.

The pods are about three inches long (8cm) and when the weather turns warm and dry the pods split open and release small flat seeds topped with long, white hairs that serve as parachutes for enabling the seeds to disperse on the wind. A pod that has split open but failed to release its seeds -- apparently because something ate the center of each seed -- can be seen at http://www.backyardnature.net/n/12/121209cx.jpg.

Seeing the pods and parachuted seeds, wildflower admirers will recognize the plant as one of the vining "climbing milkweeds." Milkweeds generally bear opposite leaves -- two leaves per stem node -- and you can see that that's the case with this vine's leaves at http://www.backyardnature.net/n/12/121209cz.jpg.

Moreover, if you tear a leaf, it'll issue white, milky latex, as milkweeds tend to do.

When I first saw these vines I assumed that they were Sand Vines, Cynanchum laeve, commonly seen in much of eastern North America. However, gradually it dawned on me that the pods were a bit plumper than what I'm used to, so I looked into the matter. It turns out that the vines here are the closely related CYNANCHUM RACEMOSUM, in the US found only in Texas, and commonly called Talayote. The name, which looks to me as if it's from Nahuatl, an indigenous language in central Mexico, reflects the fact that mainly it's a tropical American species, found throughout Mexico and much of Central America as well as northern South America.

*****

DODDER STILL FLOWERING
Another plant still flowering so late in the season, and doing so quite lustily, is the one shown at http://www.backyardnature.net/n/12/121209dd.jpg.

In that picture the flowers are the white things enmeshed among the orangish threadlike stems growing over dead or almost dead weeds. You may recognize this as a parasitic plant that goes by lots of names. I've always called it dodder, but other people might call it angel's hair, devilguts, devil's hair, devil's ringlet, goldthread, hailplant, hairweed, hell bind, love vine, pull down, stranglevine, strangleweed, tangle gut, witches' shoelaces, scald or other such name.

Basically dodder is a plant closely related to the morning-glories that wraps its stems around a host plant, sending rootlike projections called haustoria into the host's tissue, and stealing nourishment from the host. Since dodder is completely parasitic it doesn't need chlorophyll for photosynthesis, or even leaves to serve as solar collectors, so dodder consists of nothing but stems, haustoria, and flowers and fruits. In a picture made through a dissecting scope you can see an orange dodder stem twining around a host stem, with elephant-foot-like projections from which smaller haustoria arise and enter the stem at http://www.backyardnature.net/n/12/121209dg.jpg.

A cluster of our dodder's 1/16th-inch tall (2mm) flowers is shown at http://www.backyardnature.net/n/12/121209de.jpg.

A side view of other flowers appears at http://www.backyardnature.net/n/12/121209df.jpg.

That last picture shows some important field marks for distinguishing which species this is. Though it's easy to see that a dodder is a dodder, identifying dodders to species level can be hard. The Flora of North Central Texas lists ten species for that area, and I figure we have about that many here. Among identification features important to notice in the last picture are:

This dodder keys out as CUSCUTA INDECORA, sometimes called Big-seeded Dodder and other names. Some dodder species parasitize just a narrow range of host plants but Cuscuta indecora is known for attacking a wide variety of species.

Normally dodder populations are so small that they don't seriously alter the local ecology. They may weaken and cause the early deaths of individual host plants, though, and in some crops, such as Alfalfa, dodder can cause serious loss of production.

*****

RABBIT-TOBACCO TESTIMONIAL
In or November 25th Newsletter we focused on a common weed here along roads and the river, often known as Rabbit-Tobacco. I described how I'd seen the plant used medicinally in southern Mexico for lung ailments, plus I told how it had seemed to alleviate my own chest-cold symptoms that week, though I never knew to what degree such cures were psychological or really helpful. Our Rabbit-Tobacco page is at http://www.backyardnature.net/n/h/rabbit-t.htm.

This week I heard from JoAnn in Georgia who when reading the Newsletter had had a husband with sinus problems. Getting interested, she'd researched the matter more on the Internet, then decided to try the cure of a Rabbit-Tobacco tea. She reports that her patient, "... since drinking the rabbit tobacco tea this past week, has been able to breath better through his nose than in a long, long time. Has had sinus difficulties for years. Further, I noted that while he taught the Bible class this past Wednesday evening he whipped out his trusty handkerchief not one single time!"

Thinking that as fall and winter rains drench the Rabbit-Tobacco still standing and cause it to lose much of it potency, and supposing that we haven't seen the last of sinus and lung problems here, I picked a nice armload of the herb and hung it in a shed, creating an upside-down bouquet that's very pleasant to look at each time I see it. It's at http://www.backyardnature.net/n/12/121209rt.jpg.

*****

TURNIPS
I've seldom enjoyed any garden harvest more than I have this year's crop of turnips. The day after I arrived in southwestern Texas in late August I dug from my backpack a brown paper bag of turnip seeds brought from Mississippi and sowed them in a raised bed. A month later I sowed a garage-size patch of them, and now both sowings are producing prodigiously. The turnips couldn't be more flavorful and sweet. Turnips ruin during hard freezes, so I'm hoping we'll have a mild winter here and my turnips will keep producing until they bolt in late spring.

Intentionally I sowed the seeds far too thickly. As soon as the seedlings were one or two inches tall I began "thinning them out," cooking the leaves as greens. By mid September I was having a daily serving of delicious greens, often mixed with mustard greens, which also I'd sown from a bag brought from Mississippi. You can see what a typical daily harvest of turnips looks like nowadays at http://www.backyardnature.net/n/12/121209tu.jpg.

In that picture you can see that the leaves are heavily perforated with small holes caused by the Crucifer Flea Beetles we looked at a while back. Despite the obvious damage, it's hard to see how both the leaves and turnips could taste any better. However, both of my turnip sowings have been attacked and seriously damaged by leafcutting ants, which cut and carry off in small pieces entire large leaves.

The turnip plants in the picture are BRASSICA RAPA ssp RAPA 'Purple Top White Globe.' Purple Top White Globe is the cultivar name. The "ssp rapa" part of the name indicates the subspecies. "Seven-top Turnip," much grown in the US Southeast for its edible leaves, as well as one of the two cultivars known as the oil-seed-producing Canola, belong to the subspecies campestris. Chinese Cabbage belongs to the subspecies pekingensis. In human history, Brassica rapa has been one of the most important taxa of edible plants.

Wild plants of the subspecies "campestris" still can be found growing wild in Europe, though the wild ancestors of our purple-tops seem to have disappeared.

Sometimes it's hard to know whether the edible part of a plant growing entirely or partly underground, like turnips, is a modified root, modified stem, or what. Turnips are tubers, so they're roots.

*****

CUCUMBER PRICKLES
We also planted some cucumber seeds in October just to see what would happen. Now the vines are about half a foot long and are flowering. Aphids have been a problem, requiring frequent washing with soapy water to keep their numbers low.

Cucumber vines produce separate male and female flowers. Below the calyx and corolla on female flowers there are 3/8ths-inch long (10mm) inferior ovaries, -- the future cucumbers -- as shown at http://www.backyardnature.net/n/12/121209cc.jpg.

An interesting feature of that photo is that the green baby cucumber is covered with green, oval, spine tipped items. You've probably felt these "cucumber spines" on garden-grown cucumbers. They easily come off by brushing the cucumber with a cloth or the hand. A closer look at them -- with a blackish aphid at the cucumber's top -- is at http://www.backyardnature.net/n/12/121209cd.jpg.

An ever closer look at the spines, through a dissecting scope, is at http://www.backyardnature.net/n/12/121209cu.jpg.

These spines with bulging bases are similar to those we've seen on wild plants where the bases contain a substance capable of repelling herbivores. When the herbivore breaks off the slender neck, the substance is released, maybe the base of the broken off slender neck even serving as a hypodermic needle inserting the substance into the herbivore's flesh.

It's hard to say with certainty that this is the function of spines on today's cucumbers, though, since cucumbers have been cultivated for about 3000 years and today's cultivars are much changed from the wild stock. However, it's known that the spines of today's cucumbers contain concentrations of a group of compounds known as cucurbitacins, which are toxic and can deter herbivores. Various cucurbitacins are responsible for the bitterness in some cucumbers.

Often cucumber cultivars are distinguished by whether their fruits bear white or black spines. Vines producing large fruits usually used for slicing and pickling typically bear white spines, while vines with smaller fruits normally used only for pickling usually bear black spines. The ones in our picture appear to be white spines.

*****

FEATURED ESSAYS FROM THE PAST:

"On the Beauty of Raising Hell," from the August 29, 2010 Newsletter, at http://www.backyardnature.net/n/p/100829.htm.

"On the Beauty of Hunkering Down," from the February 10, 2002 Newsletter, at http://www.backyardnature.net/n/p/020210.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