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

August 4, 2013

FRESHWATER BRYOZOAN
At a low-water crossing of a one-lane gravel road a couple of miles north of the Center, clear water trickled from a metal culvert through the knee-high embankment bearing the road. The water, about 1/8th of an inch deep (3mm), sparkled as it issued onto a flat concrete apron before cascading over the edge into a small pool. Where water spread over the apron the submerged concrete was carpeted with a slimy mingling of aquatic algae, fungi and microbes. In one spot there was something unusual, though. You can see what I'm referring to -- the pea-sized, nodular, gelatinous-looking items below and to the right of my finger -- at http://www.backyardnature.net/n/13/130804bs.jpg.

They're shown closer up at http://www.backyardnature.net/n/13/130804br.jpg.

They looked soft and jelly-like, so I thought they might be frog eggs, but when I nudged one with my finger it was hard, like rock. Maybe the gloss was caused by a very thin living membrane or layer. Thinking the objects might be like barnacles cemented to the concrete, with fair force I dislodged one with a thumbnail, carried it home, and beneath the dissecting scope got a view of its surface, which under the scope appeared honeycombed with innumerable tiny holes, as shown at http://www.backyardnature.net/n/13/130804bt.jpg.

Flipping the object over, the surface that had made contact with the concrete apron displayed a pattern like you might get by cutting across soggy spaghetti that's been squeezed into a compact mass, as seen at http://www.backyardnature.net/n/13/130804bu.jpg.

So, what did all this mean?

Years ago I heard about the existence of freshwater sponges, so were these sponges? Sponge bodies are full of pores and channels allowing water to circulate through them. After the water passes through the sponge body it enters a central cavity and is discharged through a special hole. In the spaghetti picture there were no channels or pores through which water could circulate, nor did the bodies show a central cavity or pore.

At this point it occurred to me that I'd seen the compacted spaghetti pattern in rock-like fossils of creatures living millions of years ago. The creatures had been bryozoans.

Though they didn't look like our organisms, on the beach in the Yucatan we've come upon the White Tangled Bryozoan shown at http://www.backyardnature.net/yucatan/tangled.htm.

Our Lacy Crust Bryozoan that floated up on a bottle one day resides at http://www.backyardnature.net/yucatan/bryozoa2.htm.

Our oceans have harbored bryozoans for millions of years, but can they turn up in small, intermittent, freshwater streams like the Dry Frio in southwestern Texas? On the Internet I found that freshwater bryozoans do exist, and that the gross structure of some of them is like compacted spaghetti.

Though I couldn't find anything on the Internet looking like our finding, I did encounter lots of information on bryozoans provided there by Dr. Timothy S. Wood, Professor Emeritus in the Department of Biological Sciences at Wright State University in Ohio. I sent our pictures to Dr. Wood, who was generous enough to reply:

"This appears to be Plumatella fungosa, one of the few plumatellids you can identify without needing to see the statoblasts. The parallel growth of zooids all adhering to each other in a solid mass is a giveaway. We normally think of P. fungosa as a European species because it is so common there and relatively uncommon here. The colonies can grow to fist size and have been known to plague the cooling water intake structures of nuclear power plants, especially in France."

Bryozoa constitute an animal phylum all to themselves. To put that into perspective, there's the "Chordate" Phylum more or less consisting of all animals with backbones; there's the "Annelid" Phylum of segmented worms; the Mollusk Phylum, the Sponge Phylum and many other phyla. In other words, in terms of the Phylogenetic Tree of Life, there's more difference between a sponge and a bryozoan, which are in different phyla, and a fish and a human, which belong to the same phylum. Our bryozoan, then, is a whole other kind of living thing than we're used to dealing with.

Our pictures show colonies of bryozoans. The individual bryozoan animals themselves are microscopic. Each pore observed on the surface surely was occupied by one of the tiny creatures, called a  zooid. Bryozoan anatomy is so surreal and unlike anything we see in everyday life that to grasp what they're about you might enjoy visiting the Thinkquest.org website dealing with them at http://library.thinkquest.org/26153/marine/bryozoa.htm .

So, this is a wonderful discovery, one that'll encourage me to start paying more attention to scum and mire.

Now if I can only find those freshwater sponges...

*****

PASSIONFLOWER
In Mexico we found unexpected diversity among passionflower vines -- many species different from one another in sometimes subtle ways, yet always a delight to meet, for the passionflower blossom is unusual and pretty. And what a pleasure this week when I went to fetch a gravel sifter leaned against a tree just last week, to find that a passionflower vine had grown onto it in such a short period of time. You can see part of the vine bearing flowers, coiling tendrils and very wide but short leaves, so typical of passionflower vines, at http://www.backyardnature.net/n/13/130804p4.jpg.

The most famous passionflowers produce large, gaudy, almost surreal blossoms, but our picture shows what's more typical of the passionflower genus in general, which is small, greenish flowers that demonstrate the passionflower's distinctive anatomy only if you look closely. A close-up of a half-inch broad (13mm) flower is at http://www.backyardnature.net/n/13/130804p5.jpg.

The broad, greenish, petal-like items radiating from the blossom's center are calyx lobes, or sepals, doing the service of petals, for in this species no corolla is produced. The two series of many slender, fingerlike things often are referred to as the corona, or crown, and I can't think of any other kind of flower producing such a structure. However, such "fringed" crowns are typical among the passionflowers. In the flower's center the trunk-like stalk, or gynophore, bears the male and female parts atop it. The five out-curving items are stamens, only one of which -- the one at the far left -- bears an anther, for something has eaten off the other four anthers. In fact, nestled between the stamens' bases is the green, oval ovary, the future fruit, and something has eaten off the oversized, stigma-bearing styles atop it, which normally as are conspicuous as the stamens.

This is PASSIFLORA TENUILOBA, because of the shape of its leaves usually called the Birdwing Passionflower. Specializing in open limestone areas and dry caliche soils, it occurs mostly in northern Mexico, southwestern Texas and a bit of southern New Mexico.

Elsewhere we've often commented on the variety of butterflies whose caterpillars eat passionflower vines. One of our most common butterfly species here, the Gulf Fritillary, belongs to that passionflower-vine-eating group, and I'll bet that a Gulf Fritillary caterpillar ate our flower's stigmas and styles.

*****

WILD PETUNIA, AGAIN
In our travels we keep running into "wild petunias," genus Ruellia of the Acanthus Family. We've profiled two in Mexico, one in Mississippi, and a few weeks ago one here in Texas. Now we have yet another species, shown at http://www.backyardnature.net/n/13/130804ru.jpg.

A picture showing the calyx's exceptionally long, slender sepals is at http://www.backyardnature.net/n/13/130804rv.jpg.

This one is similar to most other Ruellia species: mid-summer blooming; lavender, fair-size, trumpet-shaped blossoms with five flaring corolla lobes; a knee-high plant with simple leaves bearing no teeth. However, there's one obvious difference that quickly separates this Ruellia species from most others, and that is that its flowers arise in few-flowered groupings in leaf axils -- in the angle formed where petioles attach to the stem. Flowers of most other species form at the top of the plant and often there are numerous flowers. This species' leaves also are a little broader than normal, being almost rounded at their bases.

This is the Drummond's Wild Petunia, RUELLIA DRUMMONDIANA, endemic just to a few counties in Texas and maybe a bit of adjacent Mexico. It specializes in rocky soils at woodlands edges, openings, prairies, pastures and savannahs. Ours was at the edge of a woods.

Caterpillars of the Common Buckeye butterfly feed on the plant.

The species is pretty enough to be planted in gardens, where it is noteworthy for producing flowers throughout the summer.

Wild petunias aren't closely related to regular garden petunias, being assigned to entirely different plant families.

*****

CLAMMYWEED
Of course I've had no luck convincing the right people here that our Ashe Junipers are not invasives and that they don't use more water than any other plant, so expensive efforts continue to cut them down and burn them, and people seem to feel civic minded and all-American when they do it. Below the Center, the Dry Frio's floodplain has been converted from a lovely green forest of Ashe Junipers providing wildlife habitat, retarding erosion and slowing rushing water during flashfloods, to a naked-gravel wasteland with dead junipers bulldozed into piles to be burned when the burn ban is lifted.

So, it's interesting to watch weeds invade this area. A nice one growing next to a pile of dead Ashe Junipers is shown at http://www.backyardnature.net/n/13/130804po.jpg.

A side view of a flower displaying its stamens nearly twice as long as its petals is at http://www.backyardnature.net/n/13/130804pp.jpg.

Its cigar-shaped, upward pointed fruits on conspicuous stems, or stipes, can be seen at http://www.backyardnature.net/n/13/130804pr.jpg.

The compound leaves with leaflets arising from one point atop the petiole (digitately compound), the cigar-shaped fruits, and the flowers with those very long, slender stamens will have many gardeners recognizing this as a kind of "spider-flower" -- though that name is used for just about any kind of plant whose flowers issue long, spider-leg-like stamens.

This particular "spider-flower" is POLANISIA DODECANDRA, usually called Clammyweed. The species occurs across the US, though it's strangely missing from most of the Southeast and Northwest. Three subspecies are recognized. Ours, with its stamens much longer than its petals and its leaflets with sharply acute points appears to be subspecies trachysperma, which is more restricted to the Great Plains and western states than the general species. It is described as inhabiting gravelly or sandy, sunny places along streams and other sandy places, often in disturbed areas, open woodlands, grasslands, and roadsides, so our bulldozed, gravelly floodplain must be just perfect for it.

The five clammyweed species -- species in the genus Polanisia -- are native only to North America and Mexico. They're called clammyweeds because one of several meanings of "clammy" is "unpleasantly sticky," and clammyweeds are thickly invested with glandular hairs, which causes them to be sticky to the touch.

Clammyweed's herbage is strong smelling -- though neither pleasant nor particularly unpleasant, just strong. It's a kind of purple-green, oily odor. In Herbert Covey's African American Slave Medicine: Herbal and Non-Herbal Treatments I read via Google Books that slaves brewed a tea of the herbage and/or roots, sometimes mixed with peach tree leaves, oak bark and other items, as a general medicine but especially for malaria and colds. Maybe clammyweeds are similar to a plant remembered from Africa, for there are no clammyweeds native to Africa.

When I was doing botany, the main "spider-flower" species were regarded as residing in their own family, the Caper Family, the Capparaceae. Capers are edible flower buds produced by certain plants in this family, sometimes pickled and used as seasoning. However, recent genetic sequencing has determined that species of the Caper Family fit snugly within the much larger Mustard Family, the Brassicaceae. Therefore, it seems that our clammyweeds should be regarded as members of the Mustard Family, and many experts do so. Moreover, genetics can't find any difference between our clammyweed genus Polanisia and two other genera, so really Polanisia shouldn't exist.

However, some experts just can't give up old ideas. The online Flora of North America not only continues to recognize Polanisia, but also to maintain the Caper Family as the Cleomaceae.

Whatever the taxonomic situation, I'm glad to see such a pretty native plant, even one with weedy tendencies, invading our bulldozed gravelly floodplain.

*****

DEVIL'S CLAWS FLOWERING
Maybe you recall from last January when one day Elvis the Billygoat had his front legs resting on the neighbor's fence as he bleated more piteously than usual, calling me over. When I got there I found his entire snout painfully imprisoned in one of the most bizarre seed pods I've ever seen, which you can see and read about at http://www.backyardnature.net/n/h/devlclaw.htm.

At that time we identified the seed pod as being produced by the plant called Devil's Claws, Unicorn-Plant or Ram-s Horn, Proboscidea louisianica. Nowadays Devil's Claws are are flowering, and you can see one in my garden at http://www.backyardnature.net/n/13/130804pd.jpg.

A close-up of a white flower with a syrphid fly in a blur about to enter the flower's throat and follow the golden "nectar guide" to the nectar is at http://www.backyardnature.net/n/13/130804pe.jpg.

One eye-catching feature of that photo is the dense mantle of gland-tipped hairs covering the calyx and other vegetative parts. The sticky hairs catch and often kill insects that might damage the flower, but there's no evidence that the plant derives nutrients from the capture; the plant doesn't "eat its prey." A close-up of a sepal, or calyx lobe, bristling with sticky, glandular hairs is at http://www.backyardnature.net/n/13/130804pf.jpg.

Though fruits of species in the Devil's Claws' family, the Martynia Family, the Martyniaceae, are unlike fruits in any other family, the flowers look a lot like those of catalpa or trumpet creepers, which are members of the Bignonia Family, the Bignoniaceae. In fact, genetic sequencing places the Bignonia family and the Martynia family near one another on the Phylogenetic Tree of Life. A schematic tree showing the two families -- Bignoniaceae and Martyniaceae -- near one another (4th and 5th position from the chart's bottom) can be reviewed at http://www.mobot.org/MOBOT/Research/APweb/trees/lamialesnotl.gif.

Devil's Claws is native to arid northern Mexico and as far north in the US central states as South Dakota, though it's spreading as an invasive weed in much of the rest of North America.

With such unusual fruit and sticky herbage, I'm surprised that I can't find mention of a culture using Devil's Claws medicinally. I'll bet that some people in the past sensed diabolic emanations from the fruit. Such fruits simply stir one's imagination, and it's remarkable that they begin as such normal looking, pretty flowers.

*****

MINT MYSTERY
Last winter on a gravel bar in the little Dry Frio River about three miles downstream, in a rather isolated spot, suddenly I smelled a wonderful mint odor, much sweeter and more subtle than that of the Spearmint commonly found in gardens. I'd stepped on a tiny, flowerless sprig of this unknown mint barely surviving in the gravel. What was it, and so far from any habitation, might it be a native mint? As we saw a couple of weeks ago when looking at Spearmint, there are lots of mints and unless you have flowers they can be hard to distinguish.

I carried the unknown mint sprig home and planted it in a pot. During the cold months it hardly grew at all, even as my pots of Spearmint grew like weeds. Eventually with warm weather the sprig came to life, and when hot weather arrived the sprig put on a surge of growth that had it catching up with the Spearmint. Also, almost overnight, leafy runners began growing horizontally from the plant's base, and these runners grew faster and were more substantial than those of Spearmint's stolons. All these observations didn't help me identify it, though, for what I needed were flowers.

Finally this week a single inflorescence appeared, and it's shown at http://www.backyardnature.net/n/13/130804mn.jpg.

A close-up of some of its 5/32-inch-long (4mm) flowers appears at http://www.backyardnature.net/n/13/130804mm.jpg.

On the corolla in the picture's bottom right quarter you can see that the flowers are very slightly asymmetrical. The corolla lobe pointing to the picture's right is wider than the other three lobes, and it's indented at its tip, which the other lobes are not.

All this is like we saw two weeks ago with Spearmint's flowers, so already we know that the mystery mint is very closely related to Spearmint. In fact, the similarities are so profound that I began wondering whether it might be just a different-smelling Spearmint cultivar.

When I "did the botany," however, the gravel mint revealed itself as nothing less than Peppermint, MENTHA x PIPERITA.

That "x" in the name cues us that we're dealing with a hybrid, and that surprises me because in my old books Peppermint's binomial is given as Menta piperita without the x, meaning that the plant earlier was regarded as a full species. However, genetic sequencing now makes clear that Peppermint is a hybrid between Spearmint, Mentha spicata, native of Eurasia, and Water Mint, Mentha aquatica, native to northwest Africa and southwest Asia.

It's funny, but when you know which that you're dealing with the Peppermint plant, you can't imagine that earlier you didn't recognize the plant's fragrance as that of peppermint, for it smells exactly like the peppermint sticks of my childhood.

So, without resorting to the odor of its crushed leaves, how can you distinguish Spearmint from Peppermint? One easy way is this: Spearmint leaves have almost no petioles, while Peppermint leaves have very noticeable ones.

A Spearmint leaf base with no petiole is shown at http://www.backyardnature.net/n/13/130804mk.jpg.

The substantial petiole connecting the stem and leaf blade of a Peppermint is seen at http://www.backyardnature.net/n/13/130804ml.jpg.

Who knows how our Peppermint sprout came to find itself growing in gravel beside a river in such an isolated spot?

Peppermint oil has been highly regarded for a long time. On the Internet, websites copy from one another the statement that "archeological evidence places Peppermint's use at least as far back as ten thousand years ago," but no authorities are given. It is further asserted that Aristotle wrote of peppermint as an aphrodisiac, and Alexander the Great forbade his soldiers to have peppermint because he thought it promoted erotic thoughts, reducing his soldiers' desire for fighting.

Nowadays peppermint oil is used medicinally for nausea, indigestion, and the cold. Its high concentration of menthol is regarded as good for the skin and scalp, where it is thought to increase blood flow. It's antiseptic and antibacterial. It's the oldest and most popular flavoring for toothpaste and gum.

*****

GERMANDER'S CURIOUS FLOWERS
If only to contrast Peppermint's flowers with those of another Mint Family member, it's interesting to look at the blossoms of another wildflower in that Family nowadays blossoming at woods edges and along shaded roads. You can see the plant at http://www.backyardnature.net/n/13/130804ws.jpg.

A close-up of the plant's fairly bizarre looking flower is at http://www.backyardnature.net/n/13/130804wt.jpg.

This is TEUCRIUM CANADENSE, variously called American or Canadian Germander, Woodsage and other names. It's a common and conspicuous wildflower on fairly deep, silty and relatively moist soils in most of eastern and central North America, northern Mexico and on Caribbean islands. Ours occur only in shaded spots, where the soil dries out least.

Remembering that Peppermint's four-lobed corolla was almost radially symmetrical, you can see that the Germander's corolla in extremely bilaterally symmetrical. In other words, there's only one "plain of symmetry" across which you can divide the blossom so that each resulting half is a mirror image of the other.

Despite the profound difference in outward appearance of the Germander flower and that of Peppermint, in terms of basic structure they are very similar. The flowers of each bear five calyx lobes, or sepals; each bear four stamens in two pairs of different lengths (they're "didynamous," which is a very unusual condition outside the Mint Family); both corollas are bilaterally symmetrical, even though Peppermint's corollas are only slightly so, and; the ovaries of both are deeply four-lobed, eventually maturing into four seedlike "nutlets." These are all important field marks for members of the Mint Family. Another is demonstrated by the Germander's stems at http://www.backyardnature.net/n/13/130804wu.jpg.

The stems are square in cross-section, and two leaves arise at each stem node. When you see squared stems like this bearing opposite leaves, automatically you should think of the Mint and Verbena Families. And if the unknown plant's ovaries are deeply four-lobed, then you know you have a mint and not something in the Verbena Family.

Germander is one of those mints who doesn't smell minty. Still, traditionally a tea has been made from its leaves to serve as a diaphoretic (makes you sweat), diuretic (makes you pee) and emmenagogue (makes your menstrual cycle come easier). The leaves have been applied externally to cuts as an antiseptic dressing.

*****

HEMP-TREE
More than one visitor to the little community in the Dry Frio Valley below the Center has done a double-take while passing by the sign shown at http://www.backyardnature.net/n/13/130804vw.jpg.

The reason is the bush growing immediately behind the sign. A close-up of some leaves on a growing stem of that bush is shown at http://www.backyardnature.net/n/13/130804vx.jpg.

The other day my neighbor Phred brought me such a leafy branch saying that it was growing at JW's place, and JW said that on his friend's farm in Idaho this stuff grew all along his fences, and JW said it was Marijuana.

But, if you know what Marijuana leaves look like, you know that this isn't Marijuana. Most obviously, Marijuana leaflet margins are serrated with many low, forward projecting, saw-like teeth, but these leaflets bear no teeth at all. Also, Marijuana's upper stem leaves arise singly per stem node (they're alternate) while this bush's compound leaves occur two per node (opposite). And if that isn't enough, everyone knows that Marijuana doesn't produce purple flowers, which this shrub does, as shown at http://www.backyardnature.net/n/13/130804vy.jpg.

Flower close-ups show that the lilac-colored flowers with their five corolla lobes are very slightly bilaterally symmetrical, with four stamens arranged in pairs of different lengths, as you can see at http://www.backyardnature.net/n/13/130804vz.jpg.

In other words, these flowers are very similar to Mint-Family flowers. However, Mint Family species don't have compound leaves like this bush, and this bush's stem is round in cross-section, not square, as are the mints'. This plant belongs to a family parked next to the Mint Family on the Phylogenetic Tree of Life: the Vervain or Verbena Family, the Verbenaceae. The plant is VITEX AGNUS-CASTUS, so well known throughout the world that it goes by many names, including Chaste-Tree, Chasteberry, Abraham's Balm, Monks Pepper-Tree, and, of course, Hemp-Tree. In this area Hemp-Tree makes the most sense.

But, long before people started talking about Marijuana, the Hemp-Tree was famous as an anaphrodisiac (opposite of an aphrodisiac). Pliny, in his Historia Naturalis of circa AD 77–79 reports the use by women of the plant's stems and leaves as bedding "to cool the heat of lust" during those periods when fooling around wasn't permitted because of religious festivals -- thus the names Chaste-Tree and Chasteberry.

Actually, there may have been something to that use. Modern studies show that at low doses extracts of the plant inhibit activation of the dopamine 2 receptor, causing a slight increase in release of prolactin, which can influence levels of estrogen in women and testosterone in men. In fact, nowadays certain herbal remedies on the market use Hemp-Tree/Chastetree for menstrual cycle problems and in combination with other herbs for certain hormone imbalances.

Hemp-Tree is a native of the Mediterranean region, but has escaped into the landscape across the southern half of the US, and in many other countries as well.

*****

FEATURED ESSAYS FROM THE PAST:

"Elegance Is a Compost Heap," from the December 4, 2011 Newsletter, at http://www.backyardnature.net/n/p/111204.htm

"On a Symmetry In the Human Condition" from the January 12, 2009 Newsletter, at http://www.backyardnature.net/n/p/090112.htm

*****

Best wishes to all Newsletter readers,

Jim

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