Whatever Happened to the Sphenopsida?

This and the previous post are on Edition #13 of Berry-Go-Round, the plant carnival, hosted this month over at Watching the World Wake Up. Watcher has put on a great show, so go check out the rest!

Not long ago, I was shocked to discover that some of my old college pals had disappeared. Not just the Sphenopsida, but the Psilopsida were gone, and the Lycopsida had become virtual strangers. (If you’re not conversant with Old Style Plant Classification, you may want to check the review at the previous post. Also note: The Nostalgia Alert invoked in the previous post is extended in full force to this one.)

Way back in the Dawn of Time, between the Dark Ages and the Enlightenment, back when the atom had been split but not yet fractured, between the advent and the breakup of the Beatles, I wrote a college paper called A Description and Discussion of Early Vascular Land Plants. At the time, it seemed no one was quite sure what to do with these guys, but I fell in love with them. They were the psilophytes, and a more rowdy, diverse, and exciting bunch was hard to find in 1969. Young and blinded by infatuation, I failed to see the clues... they wouldn't stick around long.

Here's Psilophyton, the ringleader (aka type genus) of the group. Look at the dichotomous branching, the cute pairs of terminal sporangia... Psilophyton princeps here represents the genus described by Sir William Dawson in 1859, but not accepted at the time. From the Lower Devonian, it was among the earliest vascular land plants, and several species are now known. The spine-like emergences on the lower stem have no vascular tissue, but the stem has a small central stele. Where did Psilophyton go when the gang broke up?

Priscilla (the Phylogenist) did not spare my feelings for old friends. She said: "Nobody seems to have come up with a good term for whisk ferns + ophioglossid ferns, but the phylum Psilophyta is defunct now. Ditto several other plant phyla. Although whisk ferns certainly don’t look like they have macrophylls, their close cousins do, so their ancestors probably did. Both extant groups have reduced root systems, whisk ferns more drastically than ophioglossid ferns."

The whisk fern she's talking about is Psilotum, a living representative of the entire group these days. (Or, classification being what it is, perhaps not even related anymore to this ancestral group.) I'm still trying to figure out why whisk ferns (or Psilophyton) are linked with grapeferns (ophioglossid), or ferns for that matter. Is it the horizontal rhizome? The circinnately coiled tips?

Continued help from Priscilla: "Monilophytes refers to the fern clade – whisk ferns, horsetails, lepidosporangiate ferns. I’m feeling lazy, so here’s a link to a reasonable listing on Wikipedia." The horsetails and their relatives were once known as the Sphenopsida, so now we know what happened to them—they got absorbed by the Monilophytes. Elsewhere, they're known these days as Equisetopsida. [Or were, on December 7th when I first downloaded this tree; now the Equisetopsida are gone too—having been converted into the Polypodiopsida. Compare the cladogram in the previous post. Plus c'a change, eh?]

A couple of the boys turned up elsewhere; you'll be glad to know they've done well for themselves. One source tells me “The Asteroxylales were originally included under the Protolepidodendrales, but they are a much more primitive lineage and have been given their own taxon (of ordinal rank). They stand midway between the Zosterophyllopsida and the more developed lycophytes.”

Judging by name recognition, I conclude that my old friends Asteroxylon and Zosterophyllum have now found good homes hanging out in and around the Lycopsida. At least by the classification scheme below:

Class Lycopsida ("club-mosses") [this list from Palaeos]

• Order Drepanophycales (ancestral types)
• Order Protolepidodendrales
• Order Asteroxylales
• Order Lycopodiales (Club "mosses")
• Order Selaginellales (Spike "mosses")
• Order Lepidodendrales = Lepidocarpales (Scale trees)
• Order Miadesmiales
• Order Pleuromeiales (intermediate forms)
• Order Isoetales ("quillworts")

I can easily believe a lycopsid affiliation for Aster; you could almost lose him in a patch of Lycopodium lucidulum; except for those frilly tops, he'd blend in quite well. He's a Scot, though, from the Rhynie Flora of Early or Middle Devonian age (400 million years ago, give or take). He and two other genera (Rhynia and Horneophyton) were described by Kidston and Lang in 1920.

As you can see, Zosterophyllum looks nothing like his pals, especially Asteroxylon, above—not surprising, as he comes from the other side of the planet. Zoster is an Aussie, a member of the Baragwanathian Flora of Late Silurian age. I think he and his cohorts, Yarravia, Hedeia, and Baragwanathia, were the earliest land plants known back when I drew these mug shots. Zoster was, as you see here, then interpreted as having an aquatic habitat. The sporangia were 3.5 cm across, distributed radially on a terminal spike. Baragwanathia, however, could pass for a long-lost brother (or grandfather, given the age difference?) of Asteroxylon. [Details here and here. Speaking of Dr. Cookson, it was this color picture of Cooksonia that got me started on this nostalgic trip in the first place. Thanks, Phytophactor!]

Just to complete the story, here's the "plant evolution" diagram I included in my paper (Fuller & Tippo, 1954, apparently my college botany textbook—how scary is that?). There at the bottom are all those other algal and fungal divisions that made up the "Thallophytes" in the classification post; and there, in a central spot, are my wonderful Psilophytales, giving rise to the ferns and gymnosperms, and anchoring plant life on land for the first time. So, though a lot has changed in the phylogenetic world since then, here's the end of my paper:

The Psilopsids are the group that best demonstrates the attainment of the necessary characteristics that enabled plants to conquer the terrestrial environment, and make possible a whole new sequence of evolution.

Defunct or not, they deserve to be remembered.

My Kingdom for a Domain to Stand Upon

Nature mocks at human categories. —Harold Bold, 1961

Nature’s mockery, however, doesn’t stop us from sorting things into boxes (classification), naming them (taxonomy), or trying to arrange them in logical order (phylogeny).

Nostalgia Alert: This will turn out to be a historical look at certain aspects of botany I’m no expert on; I’m just trying to make sense of one of the revolutions I’ve lived through. When confusion overwhelms, I’ll try to point you to more authoritative sources.

The Basic Concept (Old Style Classification)
Once upon a time, all things were organized into two boxes: Life and Not-Life. Those in the Life box became the domain of biologists, those in the other box were studied by physicists, geologists, chemists, and other scientists, and all was neat and tidy.

Similarly, in this simpler time, everything in the Life box fit neatly into two boxes known as the Plant Kingdom (Plantae) and the Animal Kingdom (Animalia). All was neat and tidy, more or less, for a few hundred years, and the people were content.

Of course, there were many, many living beings to be studied, so more boxes were created within each of the Kingdoms, making a nice neat nested structure like this:

Kingdom Plantae – Plants
Phylum (in plants it's called Division)     ends in -ophyta
  Class     ends in -opsida
   Order     ends in -ales
    Family     ends in -aceae
     Genus     no specific ending
      Species     no specific ending

Complexity ensued, and it soon was found necessary to break up this neat nesting by adding new categories (each with its own distinctive suffix) like subphyla, superclasses, suborders, and subfamilies. Great fun was had by all.

But What about Plants?
Okay, here's how the "nested boxes system" worked for Plants. Once there were the Embryophytes (plants with, well, embryos; that is, Land Plants) and Everything Else. Embryophytes were a subkingdom-level category. "Everything Else" included seven divisions of algae and three divisions of fungi (which were, of course, then Plants).
If we opened the Embryophytes box, we found a box of Tracheophytes (division) and a box of Everything Else, in this case Bryophytes (in the broadest sense). The root trache- means pipe, but in this case, it's water pipe (not air pipe as it is used in animals). So Tracheophytes are the vascular land plants, those with piping.
If we opened the Tracheophytes box, we found four new boxes. These were the four classes: Psilopsida, Sphenopsida, Lycopsida, and Pteropsida!—corresponding roughly to early land plants (mostly extinct), horsetails and their relatives (mostly extinct), clubmosses and friends (pretty uncommon), and all the green leafy things we ordinarily call plants, i.e. ferns and seed plants (Spermatophytes). The latter include all the Flowering Plants (Angiosperms) and all the Piney-Looking Things (as Watcher would call them; or Gymnosperms).

Then What Happened?
The invention of cladistics changed this whole scheme. Instead of nested boxes or graceful arching trees, we were given clade diagrams, gene-mapping, and all the new relationships technology could uncover.

In a way, cladistics isn't that different; you just turn the tree on its side, and make sure every branch splits into two parts, each of which splits again and again in a nested series. A branch is One Thing and its sister clade is Everything Else; they share a common ancestor and differ by some significant new invention. Every time it branches, the cladogram splits off a single layer of the Onion of Life. Oversimplifying again, here's a clade diagram of sorts for the Embryophyta, based on the more detailed one at Tree of Life:

If we color it to match our nested box scheme, it looks like this:


More Kingdoms
Eventually, people grew troubled by the things that didn’t quite fit properly in the two original boxes. It was true that some things had been jammed in without giving full credit to their distinctiveness, and this became especially obvious after the invention of the microscope. Someone decided we needed a third Kingdom, and now, by one scheme, we have Five Kingdoms (courtesy friend Priscilla at Big Picture Science): Plants, Animals, Fungi, Protists, and ProKaryotes. But see also: Eukaryotes for a different view of things; even more trees here.


In Summary:
It's a very exciting time in plant (and all life) science, now that classification has moved beyond mere morphology and into molecular biology. As fascinating as it all is, I'd rather be out there looking at living things and figuring out their relationships on the ground. Maybe by now, you see why I'm sort of a cynic about classification—there are just too many ways to go! Take your pick; just remember this post only talks about the tip of the iceberg.

Here's another rub: It's tough work getting genes out of fossil plants; the morphologists usually get to keep those extinct groups. That often leaves entire lineages out of the cladistic accounting (though Tree of Life has done a pretty good job of including them; 10 of the 17 clades on their Embryophyte tree are extinct). We'll talk more about them in the next post.

I'm thrilled, really I am, that classification now recognizes the important fact that bacteria run the world and gives them their just place at the root of the tree of life. (See Microcosmos by Lynn Margulis and Dorion Sagan.) It's just that I'd like the shifting sands to sit tight long enough for me to catch up!! But see Domains for evidence that's not likely to happen anytime soon!

——
For a more definitive account (and even better diagrams), please visit the American Journal of Botany's special 2004 issue on the Plant Tree of Life.

Who’s at the base of land plants?—A major controversy in land plant phylogeny concerns the base of the tree (Fig. 2). Traditionally, land plants have been divided into two groups, vascular plants and bryophytes. Although vascular plants are strongly supported as monophyletic based on both DNA evidence (e.g., Nickrent et al., 2000) and morphology (Kenrick and Crane, 1997), bryophytes are now generally thought to comprise a grade of three monophyletic lineages (mosses, liverworts, and hornworts) of uncertain relationship to each other and to vascular plants. ... In our view there is as yet no clear answer, and therefore we show the base of land plants as a tetrachotomy.

THE PLANT TREE OF LIFE: AN OVERVIEW AND SOME POINTS OF VIEW
JEFFREY D. PALMER, DOUGLAS E. SOLTIS, AND MARK W. CHASE
American Journal of Botany 91(10): 1437–1445. 2004. (give the pdf 10-15 seconds to load)

Coyote Morning...

Just got home from the Big Box store, and Husband said "there's a coyote barking out there"... Sure 'nuf! Only took a minute to find him/her with the binocs!

Finally, coyote pictures to go with my stories!! Only minutes old as I post these... (Foreground pines and fenceposts are in our yard; the junipers behind him/her about 200 yards/meters beyond.)

Bee Lady says the coyotes are gone from Red Rocks; nice to know there's still at least one around.

The dogs were inside, fortunately, but clamoring to get out. A week or so ago, a woman in the Denver metro area was attacked by a neighborhood coyote.

Wait for dark—maybe you'll get lucky and find a fresh hen! (Thank goodness it's cold, and the cats are inside!)

For the Record: 2008

[This is one of those "blog-keeping" posts that's likely to be of interest only to yours truly. Feel free to peek and yawn, or to move on to something more interesting.]

According to Blogger, I’ve posted only 69 times on Foothills Fancies in 2008, not a terrific record for what’s supposed to be my “primary” blog. Twenty-seven of those posts have been written since Watcher nudged me to get going again in November, and 42 were in the first half of the year. I love blogging, but on the whole, it’s been mostly a winter sport to date.

However, in my defense, I have been active on other blogs, and this year I’ve written almost as many posts for other purposes (91, half of which were for work) as I have for my own (103). In 2006, I took to blogging with gusto, and set up blogs for every reason I could think of, eleven in total. Some of them never really took, and today four of them are completely dormant, with no posts since 2006. Two of those were set up for time-specific purposes and have run out, e.g., a trip blog that began and ended in 2006 with a respectable 68 posts, 55 of which were written by me. Other attempts at team-blogging have proven unproductive; no one I’ve invited takes to it quite like I do, but I keep having high hopes. (I even invited Cat Woman to help here at FF, but so far she’s resisted successfully.)

2007 was a highly dormant blog year, with only 51 total posts written for six blogs, including two new ones I created for nonpersonal reasons (Lariat Loop and Mountain Parks, see sidebar).

In 2008, three new blogs were created. One, a memorial blog for a friend who died last summer, seems to have run its course but remains as a static tribute. Another is a project blog that has yet to truly catch on. The third is a place blog that I will get back to someday. The memorial blog took off briefly in June and July, concatenation of the project and work blogs created a substantial spike in August, and the work blog continued strong in September.

So, rather than the 5-month hiatus apparent from the post record here at FF, there has been no true lull, and only two slow months, April and October. I'm doing better than I think! It's a bit slow starting this year, so far, but stay tuned, hope springs eternal...

Care to take a Dip?

Mountain streams are icy this time of year, but that doesn't matter to the Dipper. He's a plucky little bird unlike any other in this—or any—neighborhood. So nondescript in coloring that he's hard to spot (or she, the females look the same), but a delight to watch if you find one. Can you spot this one? If not, click to enlarge, that might help a bit.

On my walk by Bear Creek a couple days ago, I saw two dippers chasing each other along the stream, chattering all the way, but they were too preoccupied to sit still and be photographed. (Is it mating season already? A territorial chase between males, perhaps?) I prefer their alternate name, Water Ouzel; has a ring to it, don't you think?

Yesterday, with camera along, I found just one that was willing to demonstrate their unusual lifestyle. I wish this little sequence of photos could capture the Dance of the Dipper—constantly bobbing up and down on his rock, then popping into the stream where he walks around underwater looking for shiny morsels of food. He can also fly underwater. Moments later, he pops out somewhere else. These little guys are absolutely unwettable. Like a cork with legs, he suddenly appears on another rock, upstream or down, and begins the dance again. Dippers mostly forage underwater, but sometimes they stand on a chosen rock and pick insect larvae with only their heads under the water. They can forage on the bottom of streams so fast and deep a person could not stand.

Dippers, Cinclus mexicanus, are the only birds in their family found here in North America. They naturally nest on wet mossy cliff-faces, but have benefited from new nest sites under our bridges and other streamside structures. The effects of pollution have been less beneficial, reducing their food sources, which are similar to those of trout. Healthy dipper populations, then, are indicators of high-quality mountain streams and good trout habitat.

More on dippers at the Cornell Bird Guide. The local Audubon group, the Evergreen Naturalists, has named their website and newsletter after this delightful little bird.

——
This one goes to Life Photo Meme, which publishes on Thursdays. I have trouble finding things that match their themes, but I love their concept! This week's theme is "Shiny"... Maybe the water is shiny enough?

Audrey and the A Plants

Audrey is not well… I gave her a new big pot last year, and she thrived (throve?) outside all summer, under shade cloth. But since coming inside last fall, it’s clear she’s unhappy. Audrey is a big Philodendron selloum, adopted from a friend who was moving out of state—about six years ago, I think. So Audrey and I have done well until recently. As she drops one after another of her huge leaves, I’m thinking it must be overwatering (because of that bigger pot) and I’ve been trying to dry her out.

It’s an “A” day over at ABC Wednesday, and it occurred to me to list all the plants I know personally that start with A, in no particular order but without resorting to any external aids. Maybe it’ll bring back other memories of the A-list plants in my life. A stream-of-consciousness look at phytodiversity. (Haven’t gotten far yet; this could take a while.)

A Plant Alphabet for A

Araucaria, agave, aloe, avens, Acer, Acanthus,
Anemone, apple, ash, alamo, Agapanthus,

Abies, Asclepias, Acacia, Aglaonema, Aeonium,
Artemisia, Aletes, Astragalus, Allium,
Alopecurus, aster, Androsace, Asplenium...

Amorpha, Andropogon, Agrostis, Achillea
Alyssum, Argemone, Actaea, Aralia, Aquilegia...

Amanita, Acarospora, Agaricus...

Okay, that last line is cheating a little, but fungi were plants when I grew up in botany.

(Can't believe I missed Amaryllis... but Granny Smith caught it! Please let me know your favorite A plants if I missed them—or share a story about one!)

——
Thanks to Chuck Pyle for this concept, which I’ve barely executed at this point, but I might get back to it. Chuck played a song Saturday at the Arvada Cowboy Poetry Celebration that listed all the small towns in Colorado (under 3,000 in population). It was a tour de force that had the audience spellbound. Very melodious, too; it was amazing how many town rhymes he found! He calls it Little Town Tour—check it out!

By the way, the previous post also started as a bit of an "A" post, so you'll find more "As" there.

Amazing Plants

Plants, as a group, display such a variety of incredible qualities and, yes, behaviors, that it would be impossible to list them all! One of the things I enjoy about the internet is its connectivity, and we could easily explore that quality in plants as well. Last week, though, in two clicks, I found myself at a delightful homage to the wonders of the Plant Kingdom. (Yes, I know that's old fashioned terminology, but you do know I'm stuck in the past, right?) And it reminded me of these photos I want to share with you.

Today's quality to admire in plants is resilience. To me, perhaps few demonstrations of the power of life over death impress the senses the way a plant (or entire plant community) recovering from adversity can. Adversity can strike plants in many forms, but these photos tell a story that most of us don't encounter in person: recovery after burial in volcanic ash.

Here's the caption, from the USGS website where these photos from the public domain are available free of charge.

New vegetation breaking through ash deposits along North Fork Toutle River. Cowlitz County, Washington. 1980.

The new vegetation, in this case, is a plant of fireweed (presumably Epilobium angustifolium or another species; the genus is now Chamerion), something that looks like Oxalis, and a robust-looking fern.

This little tree (a fir perhaps?) is one of the lucky ones.

USGS caption: Vegetation, blast area, Clearwater Creek, east of Mount St. Helens. Photo shows new growth on scorched evergreen. Skamania County, Washington. July 16, 1980. Photo by T. Casadevall.

July 16th, the day the photo was taken, was just two months after the catastrophic eruption on May 18th.

Historical aside: I was writing that week to an uncle of mine, a Baptist minister, and I called it "the geologic event of the [20th] century" in a rambling philosophical letter that noted the eruption was less damaging, in terms of human lives lost, than the race riots that were keeping Miami police busy at the time. (Later, the eruption's death toll outdistanced Miami's.) Uncle Art and I conducted a lengthy correspondence in 1980-81 debating the value of Nature vs. Humanity. It was a wonderful meeting of minds, neither of which were permanently altered. We agreed, in the end, that it was a Good Thing different people had different priorities.

These trees were not so lucky. No ash slowly suffocated the life out of them; their demise was instaneous. It's been more than 28 years, though. The forest, we can hope, was more resilient than the trees. It would be nice to see what it looks like today. (I really recommend you click on this one for a closer look.)

USGS caption: Within a few minutes, hurricane-force winds from the May 18 lateral blast of Mount St. Helens transformed vast stands of evergreen forest into drab tangles of giant matchsticks. The trees were stripped of their branches, toppled, and "combed" into patterns. The logging roads shown here are about 12 feet across. This view is near Elk Rock looking east. Photo by A. Post. Cowlitz County, Washington. June 30, 1980. Figure 34, U.S. Geological Survey Professional paper 1249.

What happened to that "delightful homage" I mentioned? Okay, now you can go check it out and be amazed at the abundant adaptations apparent in the world of our green friends, the plants:

Botany Without Borders, brought to us by Love Plant Life.

Atmospheric Phenomena

As nothing is very visible out there today (another whiteout), please enjoy this photo from last Thursday. The colors at sunrise made these lenticular clouds exceptional, as did the "stack of pancakes" effect of their layering.

Because lenticular clouds (you may call them altocumulus standing lenticularis if you prefer) form in the lee of mountain ranges, we see them quite commonly. Rarely are they so colorful, usually just "shades" of white.

Find great photos of lenticular clouds here.

More about them at Wikipedia.

An entire fleet, seen at NCAR in Boulder, the National Center for Atmospheric Research, where they pay attention to such phenomena.