Friday, July 24, 2009

A Sabatia Induced Rant

In Richard Manning’s book “Grassland”, he wrote the following:

I once heard a story of a man who had perfect recall, so he could never carry on a conversation. He had to live in isolation because the merest stimulus, the merest sentence from outside his own head would recall everything. All the information in his head would come tumbling forth in a great rush, and he would be crushed by the pain of seeing.
I imagine that must be what it is like sometimes to be a botanist. I have been afield with many of them, and they are different, almost invariably quiet, distant. Undeniably, they see something different from what I see, as if the knowledge of the plants lifts a veil. The whole of it is there in the plants to be read, the full soul of a place, its life and the abuses of its life, the creation’s intentions and the manifest violation of those intentions. Botanists are our shamans.

While this is clearly a romantic notion, there is some truth to it. Most botanists I know often reminisce about the days before they understood the harsh realities expressed in the flora of a place. When our non-botanists parents or friends remark at how beautiful the honeysuckles smell in the summer, we grit our teeth and try to explain to their rapidly glazing eyes why honeysuckle is bad (of course they usually miss the point and come away with the thought that they should be ashamed of enjoying the fragrance). In quiet hours I often mourn the loss of such innocence. But knowledge is a heavy burden, and I derive far greater pleasure in knowing. To me, it is knowledge that is bliss. I mention this because I believe this is one of the fundamental social functions of the botanist; to shoulder the burden of the knowledge of place and attempt to interpret the landscape for those off chasing money or fame or any other thing that an honest botanist will never know.

On this note, this year more than any other, I’ve noticed rather interesting changes in the flora. Aberrations like Platanthera lacera have come up by the thousands across the Midwest. Platanthera leucophea has had a boom year in existing populations and new populations have been found. Listera australis, a more eastern and southern species, has been discovered in Missouri and Platanus occidentalis and Morus rubra seedlings are sprouting on the bone dry ridge tops of the Chilton Creek Preserve. Just to name a few examples. On my own 16 acres I regularly take walks and I have noticed a dramatic decrease in the populations of xeric species like Krigia dandelion, Helianthus mollis, Helianthus occidentalis, Spiranthes vernalis, Gymnopogon ambiguus and Polygala incarnata while witnessing an increase in mesic species like Dichanthelium laxiflorum, Salix humilis, Pedicularis canadensis and Senecio aureus. However the most dramatic change, in terms of population and sheer flora display, has been Sabatia angularis (photos distributed throughout this entry).

In a typical Ozark summer, S. angularis blooms in scattered populations across prairies and old fields; a plant here, a plant there. This year, however, the populations are large and dense and the plants are huge! The field in front of my house, in which Sabatia typically goes relatively undetected is literally pink with plants. While driving across the Ozarks one cannot help but notice their abundance. A naturalist friend of ours just sent us a letter documenting the phenomenon throughout Texas County as well. I speculatively attribute this phenomenon to the past two wet years that have followed several very dry years (at least in the Ozarks). I’m sure there is more to the story than this simple answer. And I’m sure this is all within the ebb and flow of the natural order of things where variations in seasonal severity lend boom and bust years to a resilient biota. But I fear there is very little documentation of such phenomena and any trends that may arise. Sure, a handful of rare species are occasionally tracked given funding and time, but who is watching the big floristic picture? There are various projects monitoring the phenology of plants in an attempt to document the effects of climate change, but what about the changes in structure and composition of natural communities in general that may be outside the narrow scope of climate change. Regardless of cause, what if the Ozarks are getting wetter, for example? This would have tremendous effects on glade and woodland restoration/conservation efforts to say the least.

This brings me back to the main point. In the heyday of ecology, botanist/ecologist like Lucy Braun, Henry Cowles and Julian Steyermark spent countless hours documenting the flora through descriptive floristics projects. This included such elements as a list of species, their abundance and frequency and the overall structure of the vegetation of the site. All this from quadrat and transect data. Now such techniques are largely considered to be only of historical significance by academics and are rarely undertaken and almost never funded outside of an occasional study conducted by a graduate student. When I mention this void in the sciences to professionals their reactions are rather dismissive, as though I am evoking some sort of nostalgia-based concept of scientific responsibility rather than anything of ecological or social importance. Perhaps if the topic were polar bears, they would lend a sympathetic ear. It is increasingly obvious that respectable botanists that can identify plants without flowers and the aid of keys, dying breed that we may be, are being underutilized and certainly underappreciated. Sure, our skills are often called upon to put together an occasional species lists or partake in a bioblitz, but these activities lack any ecological significance outside the stark documentation of occurrences. They provide no information about abundance, structure or conservation. Somehow a species list has become an acceptable replacement for actual data.

In a society that continues to destroy natural communities and impact natural processes at an ever accelerating pace, now is not the time to stop describing the remnants. From the ever shrinking crumbs of our natural system, we may yet be able reconstruct or at least envision the cake. To most, crumbs aren’t exciting. After all, far reaches of the tropics still have big pieces of cake upon which to feast the intellect. Sadly, most academic botanists lack the ability to even identify the most common species in the remnant woodlots behind their expensive suburban homes. Meanwhile the only plants most botanists under the employ of state and federal governments get their hands on are the various trees used in the manufacture of their pencils. In effect, environmental consultants are conducting the lion’s share of descriptive ecology, though often by poorly trained staff and for reasons not conducive to ecology or science. So while the botanical “shamans” mentioned by Manning may be a bit of a misnomer, where are they? And who is going to tell us how the natural system is responding to changes, natural and human induced? How will we detect localized extinctions inherent to a fragemented landscape? Gerould Wilhelm once said, “You cannot take care of what you cannot see”. So where are the seers and why aren’t they seeing?

Sunday, July 12, 2009

Argyrochosma dealbata

While running transects across the grassy ledges and shelves of Hercules Glades Wilderness in Taney County Missouri, I paused to wipe the accumulation of sweat and juniper needles from my brow. As my heart rate approached conditionally normal, given the heat, my eyes focused on a tiny patch of bluish vegetation clinging to the otherwise salt and pepper fa├žade of the sun and lichen aged limestone rock; the jutting and ever dissolving bones of the Ozarks. I leaned in.

Puzzled, I looked around the ledge and discovered eight more small clumps of this little fern. I am accustomed to seen Cheilanthes feei on such rocks in such habitat, but this was strikingly different. In fact, Chelanthes feei was growing on the same ledge some 24 inches away and made for apt comparison. Hot blood squeezed through my brain and I was surprised when the name Notholaena dealbata surfaced; a fern I had only seen on glades along the Blue River in Kansas City. A quick cruise through several cold blooded references verified the identification.

Notholaena dealbata (Powdery Cloak Fern) is currently referred to as Argyrochosma dealbata on the USDA PLANTS website. Taxonomically, it seems to fit somewhere between the genus Cheilanthes and Pellea. I can certainly see the similarity with the latter. The core of its range extends from eastern Kansas and southwest Missouri into Oklahoma, Arkansas and Texas with outlying populations in Illinois, Kentucky and Nebraska. It only occurs on outcrops of calcareous rock.

The sweetest thing about Argyrochosma dealbata is not the blue coloration or the revolute margins of the pinnae, but the farina of the abaxial surfaces of the pinnae (the white color in the photo below is the farina).

The farina, in this case, is a waxy exudate. I can only speculate as to its function, but won’t. The dark spheres are sporangia each containing 64 spores. Morphologically, the genus Argyrochosma differs from Cheilanthes and Pellea in the possession of farina and was split from Notholaena based on a different chromosome number (n=27). Argyrochosma means “silver powder” in reference to the farina.

I have always been enamored with small ferns. This is probably my favorite, for obvious reasons.

Wednesday, July 1, 2009

Silphium asteriscus

I truly enjoy the genus Silphium. It has an exciting yet strangely cohesive range of morphological variation. From humble colonies of S. integrifolium to the stoic and lofty stems of S. laciniatum, from the cool, rough texture of S. terebinthinaceum to the dense flocculence of S. mohrii (see below), they never fail to please.

Here is a veiny crowd pleaser; the leaf of Silphium compositum from northern Alabama.

In the Ozarks Highlands of Missouri, I annually anticipate the lemony blooms of S. asteriscus that begin dazzling the understory of our acid upland woodlands soon after the summer solstice.

Silphium asteriscus (Starry Rosinweed, if you must) occurs throughout the southern United States in acidic woodlands. When young, it produces a basal rosette of ovate to lanceolate leaves. When it bolts to flower, the leaves are alternate along the stem, as opposed to S. integrifolium which is opposite leaved (and which never produces a basal rosette).

In spite of the dramatic range in morphology within the genus, all Silphium have a unique suite of characters. They all have thickish leaves with isodiometric venation (see leaf of S. asteriscus below).

The leaf margins of Silphium are often toothed and each tooth has a yellow callus at the tip (see blurry photo below).

Strangely, species or individuals lacking teeth have calluses on the margins where teeth either were or should be. Most all species have stiffly pubescent leaves and stems. The involucral bracts of the capitula (flower head) are broadly ovate to deltoid in outline and much wider than the closely related Helianthus (sunflowers). Florally, the disk flowers of Silphium are sterile and have only one style, as opposed to Helianthus which has fertile disk flowers with dichotomous styles.

Large or small, laciniate or entire, Silphium is a fine genus. Most every floristic region of eastern North America has at least a couple of species of Silphium (the number increasing to the south and east). As they are beginning to come into bloom throughout the range, be sure to take some time to observe them closely. Feel their cool, rough leaves, their whiskery stems and their stiff phyllaries. You won’t be disappointed.