April 6,  2009

GRAY TREEFROG
During the afternoon cornbread-fixing campfire a leaf seemed to take a jump, so I went to look and it turned out to be a gray treefrog. The name "gray treefrog" isn't capitalized because I'm not sure of the frog's identity. It was just a gray frog, which you can see at https://www.backyardnature.net/n/09/090406tf.jpg.

The doubt about the name arises from this sentence in the Audubon field guide: "The two species of Gray Treefrog are identical in appearance, and since their ranges overlap extensively, they cannot be distinguished in the field." So, two identical, gray frog species occur here: the Common Gray Treefrog, HYLA VERSICOLOR, and; Cope's Gray Treefrog, HYLA CHRYSOSCELIS. The two species are recognized as separate not only because Cope's calls with a faster trill but, more importantly, it has only half as many chromosomes as the Common Gray. They don't interbreed in Nature.

Actually, my first thought when I approached the somewhat warty frog had been that it was a small toad. However, you can see that the tips of this frog's toes are more rounded than a toad's, plus behind the bulging eyes there are no tumor-like, poison-producing parotoid glands, which toads have.

Treefrog toe-tips are rounded and enlarged because they serve as sticky adhesive pads for climbing trees. Both gray treefrog species typically are found in trees and shrubs in or near permanent water, so maybe our individual was on a hop-about looking for a new home or a mate. One problem with that theory is that the literature assures us that the two species are nocturnal and shouldn't be on the ground on a sunny afternoon, so, who knows?

When I clicked the shutter during one shot the frog lurched away, not only causing a blur but also revealing bright, yellow-orange spots on the undersurfaces of the frog's back legs, as shown at https://www.backyardnature.net/n/09/090406tg.jpg.

Why would a nocturnal frog possess such colorful spotting in a place seldom displayed? First, our gray treefrog species obviously are not entirely nocturnal. During daylight wanderings such as our frog was making the yellow spotting serves for "flashing": When the frog leaps to escape a predator, the bright pattern for a moment may surprise or distract the enemy long enough to help the frog get away.

And why would Nature create two identical-looking and -behaving frog species in the same geographical location? Maybe that's best answered by evoking Nature's pure passion for diversity, and Her tendency to experiment in every way imaginable. I suspect that with time the two species either will evolve so that they don't compete in the very same ecological niche, or else one species will extirpate the other.

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TIGER SWALLOWTAIL ON A THISTLE
The other day an Eastern Swallowtail butterfly, PAPILIO GLAUCUS, was working at one of the Bull Thistles I spoke of last week and, despite the species being so common here, I just had to go take a look. What I saw when I kneeled down next to the thistle is at https://www.backyardnature.net/n/09/090406sw.jpg.

That's a male with a wingspan of nearly five inches (12 cm); females are black with powder-blue dusting.

So, the message here is that just because we see something every day we shouldn't forget to sometimes pause and take a closer look. Get down and poke your nose up as close to things as possible, and admire and wonder. Really, I myself had almost forgotten how beautiful this butterfly is, especially when you're so close you can see the black legs, antennae and coiling proboscis so nervously and delicately probing, testing, and trying to deal with the thistle's stiff, stickery floral-head bracts and the tightly packed forest of narrow-throated, purple composite flowers themselves. What I saw was a lilting piccolo melody ephemerally and lightly intoned among base trombone yowlings and sharp drum jolts.

Taxonomically, the Tiger Swallowtail situation isn't as simple as it used to be. In the Appalachians our Papilio glaucus is replaced by the closely-related, larger and only recently described P. appalachiensis and, in the north, it's replaced by the closely related P. canadensis. These three species can be very difficult to distinguish, and earlier were all lumped under our P. glaucus.

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ROVING TENT CATERPILLARS
This week I've run across several two-inch long Eastern Tent Caterpillars, MALACOSOMA AMERICANUM, one of which you can see atop my hand at https://www.backyardnature.net/n/09/090406tc.jpg.

To figure out why these lone, wandering, as-large-as-they-get caterpillars are suddenly turning up I reviewed the tent-caterpillar life cycle. Here it is:

The adult moth lays her eggs in late spring or early summer. The eggs hatch the following spring, just as tree buds begin expanding. Newly hatched caterpillars immediately start building a silken tent in a tree, expanding it each day. The caterpillars feed three times daily -- just before dawn, at mid-afternoon, and in the evening after sunset. When they leave their tent they add silk to it, move to nearby leaf-grazing limbs en masse, feed, then return to the tent where they rest until the next feeding period. Right before metamorphosing they begin feeding only at night. When they're ready to metamorphose they wander off and build cocoons in protected places. Adult moths, which are nocturnal, emerge about two weeks later, mate and the females lay eggs the same day they emerge from their cocoons. The females die soon thereafter.

So, wandering Eastern Tent Caterpillars encountered nowadays already have built their tents and eaten and grown, and now are looking for protected spots in which to construct cocoons where they can metamorphose. A tent hangs inside a mostly defoliated Black Cherry tree near my trailer, and you can see it at https://www.backyardnature.net/n/09/090406td.jpg.

That tent, about the size of a basketball, full of caterpillar feces and dead caterpillars, is abandoned, having served its purpose by spawning at last some of the wandering caterpillars I'm seeing these days.

Wikipedia provides an especially informative page at http://en.wikipedia.org/wiki/Eastern_tent_caterpillar.

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LYRELEAF SAGE FLOWERING
Lyreleaf Sage, SALVIA LYRATA, is a native, woodland- growing, eastern US plant so pretty that it's included in almost all wildflower books, yet also it can be so abundant along highways, in lawns and other disturbed habitats that sometimes it's called a weed. You can see its unusual leaves and inch-long blossoms at https://www.backyardnature.net/n/09/090406sa.jpg.

Along the Natchez Trace Parkway between here and Nashville at this time of year there are stretches of mile after mile of roadside tinged blue with close-together, flowering Lyreleaf Sages.

At https://www.backyardnature.net/n/09/090406sb.jpg you can see how nicely the flowers are adapted to pollinators such as bees who land on the corolla's lower lip, then follow striped "nectar guides" into the flower's depths where nectar awaits. On the flower at the right, notice how an entering bee's back already dusted with pollen from another flower first touches the wishbone-shaped, stigma-tipped female style, depositing male pollen there, then as it continues its back is daubed with a new load of pollen from this flower's stamens.

The blossom's pollination strategy is even more ingenious than that. Look at the unique stamen shown at https://www.backyardnature.net/n/09/090406se.jpg.

There I've cut lengthwise through the blossom so that you're seeing one of the flower's two stamens as it arises from the corolla's floor and arches to the ceiling. The stamen's stemlike filament is branched at its top, the top branch bearing a fully formed, pollen-producing anther-half while the lower arm bears a less developed anther-half. That lower anther and arm project into the corolla's passageway so that a pollinator enters it must shove against it. When that bottom arm is nudged backwards, the top arm is forced downward, daubing pollen on the pollinator's rear end!

Lyreleaf Sage belongs to the same genus as Scarlet Sage of gardens, and Scarlet Sage flowers have similarly tricky stamens. Sages are members of the Mint Family.

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FEATURES OF THE MINT FAMILY
Not all members of the Mint Family, the Labiatae, smell minty. Lyreleaf Sage, for instance, doesn't. Since the Mint Family is so large and important, you may enjoy knowing what features usually but not always distinguish its members.

First, Mint-Family flowers usually are "dog faced" -- they have bilateral symmetry instead of the radial symmetry displayed by most flowers. In bilaterally symmetrical flowers there's only one way you can cut across the flower so that one cut half perfectly mirrors the other half. In radially symmetrical blossoms there are several ways.

Second, mint plants produce two leaves per node instead of the more common single leaf; they're "opposite."

Third, the stems of mint plants are square in cross section, as shown by the Lyreleaf Sage's stem at https://www.backyardnature.net/n/09/090406sc.jpg.

Finally, if you peep into the flower's cuplike calyx after the corolla has fallen off after pollination you'll see that instead of there being a single oval ovary as usually is the case, the ovary is divided into four seedlike "nutlets," as shown so prettily at https://www.backyardnature.net/n/09/090406sd.jpg .

The Mint Family and the Verbena or Vervain Family, the Verbenaceae, are closely related and, especially in the past, were not always easily differentiated. Recent gene sequencing has caused a number of Verbena Family genera to be shifted into the Mint Family, so now family differences are clearer and the above features are more likely to accurately lead to "mints."

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FALSE GARLIC SUPERFLUITY
A very conspicuously flowering plant nowadays almost omnipresent in disturbed soils everywhere, especially roadsides and lawns with abused, sterile soil, is the False Garlic, NOTHOSCORDUM BIVALVE. This species' penny-size, white flowers and grassy leaves sprout from a Ground-Ivy carpeted spot in Karen's yard at https://www.backyardnature.net/n/09/090406nn.jpg.

False Garlic isn't a garlic at all but it's closely related to it as well as to the onions, and looks a lot like them. However, False Garlic doesn't have a garlicky odor. False Garlic, garlic and the onions all reside in the newly constituted Onion Family, the Alliaceae, and share the same general body form and inflorescence type, and all similarly sprout from bulbs. Before gene sequencing showed how unusual the group really is, False Garlic, garlic and the many onion species all resided in the Lily Family.

At https://www.backyardnature.net/n/09/090406no.jpg you can see that False Garlic's flower is elegantly simple enough for you to get onto your hands and knees and admire it. At first glance it's like the "Standard Blossom" at https://www.backyardnature.net/fl_stand.htm used to explain basic flower structure because its parts are so distinct and easily recognizable.

See how the six male stamens composed of orangish, pollen-producing anthers atop sticklike filaments arise at the base of the six white "petals," with the female oval ovary nested in the middle, and topped by a stiff, slender style tipped with a knobby stigma. The main differences between False Garlic's flower and the Standard Blossom is that False Garlic's showy parts number six instead of the usual five, plus there is no distinct calyx and corolla. Calyx and corolla are merged into one corolla-like thing called a perianth; the "petals" of such a perianth are called "tepals."

Unlike most weedy plants, False Garlic is native American, mostly from the US Southeast and Mexico. Another name for False Garlic is Crow Poison. On the Web I find the plant labeled as poisonous but also there's a fellow who says that baked they're probably not "dangerously poisonous."

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BEFORE THE HEARTS BURST
Yet another very common plant -- a slender, lithe bush about shoulder high -- flowering now with very unusual and pretty blossoms you'd only notice if you were consciously walking around looking at things closely is that of the Hearts-a-bustin' or Strawberry Bush, EUONYMUS AMERICANUS. Its flower clusters curiously held almost flush with its paired, or opposite, leaves jutting out at right angles to the stem are shown at https://www.backyardnature.net/n/09/090406eu.jpg.

Its curious, greenish-yellow blossom is shown close-up at https://www.backyardnature.net/n/09/090406ev.jpg.

The five large, roundish, veined items are petals and the five much smaller, yellow things are pollen producing anthers atop very short filaments. The broad, smooth, round object occupying the flower's center is something fairly distinctive for the genus Euonymus. It's a disk attached to the calyx and completely covering the ovary lying hidden below the disk. In the disk's very center you see a very short stigma-bearing style poking through. Pollen from other flowers will germinate on the stigma and the male sex germ will migrate down through the style to the ovary below the disk. I'm guessing that the disk's function is simply to protect the delicate ovary.

None of this explains those names, "Heart-a-bustin'" and "Strawberry Bush." It's the fruits that people notice and inspire the name givers. In the fall the fruits turn red and warty like strawberries, then they BURST open releasing glossy, orange-red seeds. The fruits are very conspicuous and if you walk in eastern US forests where the species lives you'll probably recognize them in the fruit picture at http://www.wildflower.org/gallery/result.php?id_image=18943.

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RED HONEYSUCKLES FLOWERING
At woods edges one of the most striking presences nowadays is the Red, Trumpet or Coral Honeysuckle, LONICERA SEMPERVIRENS. Against the forest's deep green background the vine's dangling clusters of narrowly trumpet-shaped flowers, red outside and yellow within, is really something to see, as shown at https://www.backyardnature.net/n/09/090406hs.jpg.

At https://www.backyardnature.net/n/09/090406ht.jpg you can see an unusual feature of the Red Honeysuckle's leaves: While most of its leaves are simple and occur in pairs along the slender, twining stem, in this species, immediately below the flower cluster, the first pair of leaves are grown together, or "connate," into one blade through which the flower stem, or peduncle, passes right through the blade's center. When a stem seems to pass through a leaf like this, the leaf is said to be "perfoliate."

Also a bit unusual for the genus Lonicera, of which around 180 species are listed, mostly from China, is that the corollas of this species are more or less "radially symmetrical." Most honeysuckles, like the super-abundant invasive Japanese Honeysuckle, are bilaterally symmetrical, with four corolla lobes pointing upward and one below. Also, most honeysuckle species bear deciduous leaves, while our Red Honeysuckles are evergreen. In other words, our Red Honeysuckle is something of an unusual honeysucle species.

As you might guess, anything this pretty is threatened not only by the usual habitat destruction but also by people digging it up for planting around their own homes, where it almost invariably dies. People usually dig them when they're most pretty, which is early spring, exactly when the plant needs all its roots to support new growth, and of course digging them up destroys most of their root system. Red Honeysuckles used to be fairly common around here but now you only occasionally see them.

The species is native to most of eastern North America, and already is listed as endangered in Maine.

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ELEGANT SOUTHERN SHIELD-FERNS
I've mentioned that by far our most common fern here is the Christmas Fern. You can see a patch near camp at https://www.backyardnature.net/n/09/090406f_.jpg.

In our upland, loess-soiled, oak/pine/hickory forests, maybe one in a thousand ferns is another species. Probably the most frequent "other species" is the Southern Shield-Fern, THELYPTERIS KUNTHII, shown at https://www.backyardnature.net/n/09/090406fn.jpg.

Despite this fern's elegant form and the neat way its lower pinnae diminish in size and point downward, distinguishing the species from similar ferns isn't particularly easy. To separate it from the Hairy Maiden Fern, Thelypteris hispidula, for example, I had to compare minor differences in venation of the pinna subdivisions, the pinnules.

These two very similar ferns are definitely distinct species, however, because Southern Shield-Ferns are tetraploids, with a chromosome number of 72, while the chromosome number of Hairy Maiden Ferns is only 36 -- they're diploids. Therefore, these two fern types can't interbreed, and that's a condition at the very heart of the definition of what a species is.

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FERN DIPLOIDS AND TETRAPLOIDS
Speaking of fern diploids and tetraploids, the diploid condition is normal for organisms. In diploid species the cell nuclei contain two sets of chromosomes, one set inherited from each parent.

In ferns, the fronds are diploid but reproductive spores are haploid -- each spore carries only half the chromosome number of the parent frond. Halving of the diploid chromosome number to produce haploid spores occurs during the cell division process known as meiosis. However, very, very rarely meiosis goes haywire and the chromosome number is not halved. Diploid spores are produced with the same number as the parent frond.

When fern spores germinate, they form free-living little plants more like green thumbnails than fern fronds, called prothalli (singular prothallus). You can see prothalli under the heading "Fern Reproduction" halfway down my Fern Page at https://www.backyardnature.net/ferns.htm.

It's on these tiny, seldom seen prothalli where the male sex germ unites with a female sex germ, resulting in a sprout that eventually develops into the thing we think of as a fern.

Well, if meiosis has messed up and a diploid spore has been produced, the prothallus emerging from the spore will be diploid, and when the prothallus's diploid male and female sex germs unite, the resulting embryo will grow into a frilly fern plant that will be tetraploid -- it'll bear four sets of chromosomes, twice the number it should have!

When this happens, sometimes the resulting tetraploid survives and passes on its high chromosome number to offspring, and that seems to have been the case with our Southern Shield Fern. Of course once a population is for any reason genetically isolated from its parent species it can begin evolving along its own lines, and that accounts for the tiny differences between the two species mentioned above. When this kind of tetraploid creation occurs, basically you get an instantly produced, whole new species!

This is not the way most species arise, but among some groups of organisms it's much more common than others.

If you'd like to know more about this kind of genetic unorthodoxy, query a search engine on the interesting keyword "polyploidy."

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THE SIXTH MIRACLE, BUT SURER NOW
For some years I've mentioned from time to time my belief that during the creation of the Universe, or Nature, at least six inexplicable, absolutely mysterious and beautiful miracles have occurred. Here they are:

When I first wrote down those miracles in my November 24, 2002 Newsletter, I felt I had an important insight, but I wasn't sure. Now at age 61-½ I want to say that with each passing day and with the discovery of every new thing for me, I've grown more and more sure that the Six Miracles have really occurred, and that Nature -- the Universe -- is more mysterious and beautiful than I'd ever dreamed.

In the 2002 Newsletter I wrote:

"I think that The Sixth Miracle is occurring just now -- "now" being the last few millennia. This blossoming is taking place as a greater and greater percentage of us Homo sapiens at least sometimes, at least briefly, project our minds beyond thoughts dealing with the daily maintenance and navigation of our bodies -- the hurting feet, the mechanics of acquiring mates, power and status, etc.

The Sixth Miracle flashes into being whenever any one of us reflects on the Cosmos, the selfless and beautiful abstract patterns in music and art, the pale-orange broomsedge field lightly touched with frost at dawn as the White-throated Sparrow sings its "I'm here" song... and is moved to emotion."

A few Newsletters ago I pointed out that Nature accepts in her sustainable systems certain strategies that most humans find objectionable: "lying, robbery and murder." I should have mentioned then that the Sixth Miracle of Nature assures humans that in human society "lying, robbery and murder" are not inevitable.

For, when the Sixth Miracle of Nature ignites in our lives, we become so overwhelmed by the Truth of the Universe's majesty that there's simply be no need to lie, to make things seem better. Anyone touched by The Sixth Miracle is bound to be so inspired by the bounty and generosity of Nature in general that the need to rob  never occurs to them. Discovering the Sixth Miracle blossoming in our lives, it's inevitable that we become so touched by the absolute beauty and mystery of life that the mere idea of murder is incomprehensible.

We must fix the concept of the Sixth Miracle of Nature in our minds and walk toward it every day, never losing sight of what it is offering. We must never forget to do what we can to encourage it to blaze brightly in our own lives, and we must never stop trying to help one another know about the Sixth Miracle, so that everyone can benefit from it.

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GREYHOUNDING AGAIN
Today, Monday, after this Newsletter is issued, once again I'm hopping onto a Greyhound bus and heading into new territory. In a week's time I'm not sure I'll be in shape to issue the next Newsletter at the usual Monday time because this is going to be a long haul. If I miss the next Newsletter, maybe I'll have things together in two weeks. See you on the other side.

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Best wishes to all Newsletter subscribers,

Jim