Botany

Friday Flower – Dwarf Spiderwort

/ Ted C. MacRae / 21 Comments

Living at the foothills of the Ozark Highlands, I sometimes forget how unique the biota of this ancient landscape truly is. More than 200 species of plants and animals are largely restricted to the region, with around 160 of these being true Ozark endemics found nowhere else on earth. The biodiversity of the region stems from the landform’s unusual geology, topography and hydrology, it’s ectotonal position within the North American continent, and its distinction as the only significantly elevated landform between the Appalachian and Rocky Mountains. Many Ozark endemics are found in the region’s abundant caves and sinkholes, formed by underground dissolution of its massive limestone/dolomite bedrocks. Others represent isolated populations of more typically northern plants and animals that found refuge here during the Pleistocene glacial advances. Still others evolved during periods of isolation when vast inland seas covered much of the continent’s interior.

Tradescantia longipes, known locally as dwarf spiderwort or wild crocus, is a particularly exquisite Ozark endemic found scattered in dry igneous woodlands of the Missouri’s St. Francois Mountains and Arkansas’ Ouachita Mountains. I first saw this species two years ago in May at Crane Lake in the heart of the St. Francois Mountains, and the plants shown here were seen this past April in the igneous woodlands of Sam Baker State Park at the southernmost extent of the St. Francois Mountains’ igneous exposures. The genus to which this plant belongs contains some much more widely distributed (though no less striking) members (e.g. T. ohioensis, which I featured in my first “Friday Flower” post). Tradescantia longipes flowers are similar to those of T. ohioensis, but the plant differs from most others in the genus by its short, squat habit of growth and strictly basal leaves.

One feature shared by T. longipes with all other members of the genus is the dense fringe of hairs arising from the stamen filaments.  I discussed these in my first Friday Flower post, noting that each of the 70-100 hairs per filament is composed of a chain of about 20 large, single cells – easily seen with low magnification. While their sensitivity to radiation and chemical mutagens has been recognized for many years (the hairs turn pink when exposed to radiation), less seems to be known about their natural function for the plant.  It is interesting to note, however, that the flowers of Tradescantia and related genera rely heavily on insects for pollination (primarily bees and bee flies), yet they do not produce nectar.  Faden (1992) has speculated that the stamen hairs might combine with floral scents and the nearly pollenless anthers to deceptively attract insects, provide footholds, retain pollen fall, and influence the pollen-collecting behavior of the insects.

Photo Details: Canon 50D (ISO 100, 1/250 sec, f/14-18), Canon 100mm macro lens, Canon MT-24EX flash (1/4 ratio) w/ Sto-Fen diffusers. Post-processing: levels, unsharp mask, minimal cropping.

REFERENCE:

Faden, R. B.  1992. Floral attraction and floral hairs in the Commelinaceae.  Annals of the Missouri Botanical Garden 79(1):46–52.

Copyright © Ted C. MacRae

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Friday Flower – Pawpaw

/ Ted C. MacRae / 28 Comments

As my friend Rich and I stood in the verdent understory admiring the spectacular panicles of red buckeye punctuating the green lushness, a small brown flower on a leafless branch above me caught my eye.  “Pawpaw!” I exclaimed, perhaps partly in amazement that it took us awhile to notice the trees that were, in fact, all around us.  Pawpaw (Asimina triloba) is a member of the only temperate genus in the otherwise exclusively tropical and subtropical family Annonaceae (Custard Apple Family).  Although not nearly as restricted in occurrence in Missouri as the red buckeyes with which they were growing, they are nevertheless always a treat to see. Scattered throughout the state, they can be found growing in bottomland forests, ravines in mesic upland forests, along woodland streams, and at bases of bluffs (Yatskievych 2006).

Pawpaws are, of course, famous for their large edible fruits, sometimes called Indian bananas, Missouri bananas, Michigan bananas, [insert eastern state here] bananas, etc.  Technically, however, the pawpaw fruit is a berry, since it is derived from a single pistil and has multiple seeds embedded within the pulpy matrix.  I’ve not tried the fruit myself, not for lack of desire but rather an inability to find them when they ripen in fall before the birds and mammals get to them.  Some effort has been made to cultivate the plant for fruit production, but low fruit set seems to be a persistent problem due to reproductive self-incompatibility.

Pawpaw also famously serves as the larval food plant for the zebra swallowtail butterfly, Eurytides marcellus (family Papilionidae).  Beyond this, however, there seem to be not many insects associated with the plant.  I have collected dead wood of pawpaw in an effort to determine the species of wood-boring beetle species that are associated with it.  The only species I’ve reared is the longhorned beetle, Elaphidion mucronatum (whose common name “spined oak borer” belies the fact that it is one of the most polyphagous of all North American species), and two other longhorned beetles, Eupogonius pauper and Urgleptes querci (also highly polyphagous), have also been reported being reared from dead wood of this plant.  I have not associated any jewel beetles with pawpaw, nor have any such associations been reported in the literature.  It would appear that woodboring beetles are not fond of the soft, weak wood of pawpaw, perhaps due to the plant’s annonaceous acetogenins with known pesticidal qualities (Ratnayake et al. 1993) (acetogenins are also under investigation as anti-cancer drugs).  Other poisonous compounds, chiefly alkaloids, are found in various parts of the plant, especially the seeds and bark, and likely play a role in herbivore defense. Insect pollinators also seem to be infrequent, as I have not noted any insects on its flowers. Most members of the family are pollinated by beetles (Yatskievych 2006), but the meat-colored, downward-facing, not-so-sweet-smelling flowers of pawpaw suggest pollination by flies, perhaps those attracted to carrion.

REFERENCE:

Ratnayake, S., J.K. Rupprecht, W.M. Potter, and J.L. McLaughlin. 1993. Evaluation of the pawpaw tree, Asimina triloba (Annonaceae), as a commercial source of the pesticidal annonaceous acetogenins. p. 644-648. In: J. Janick and J.E. Simon (eds.), New Crops. Wiley, New York.

Yatskievych, G. 2006. Steyermark’s Flora of Missouri, Volume 2. The Missouri Botanical Garden Press, St. Louis, 1181 pp.

Copyright © Ted C. MacRae 2010

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Friday Flower: Red Buckeye

/ Ted C. MacRae / 14 Comments

Beetles, spiders, and snakes were not the only delights that Rich and I saw as we hiked the lower stretch of the Ozark Trail’s Wappapello Section in early April.  Entering the rich, moist, east-facing slopes overlooking the Black River valley, the oaks and hickories were still in the early stages of bud break. A lush, green understory, however, spread out before us, punctuated by the striking inflorescences of red buckeye, Aesculus pavia (family Hippocastanaceae). Among the first trees to bloom in spring, red buckeye is unmistakable in the field due to its red flowers and palmately divided leaves.

Red buckeye is native to the southeastern U.S., just reaching Missouri in the southeastern Ozarks (though cultivated further north). This makes it less well-known than the more widely distributed Ohio buckeye, Aesculus glabra (absent only from the southeastern lowlands and northwestern corner of the state, and easily distinguished by its white inflorescences, larger size, and spreading growth habit).  Like that species, the seeds and young foliage especially are poisonous if eaten due to glycosidic alkaloids and saponins.  Native Americans roasted, peeled and mashed the nuts into a meal called “Hetuck.”

I first encountered this species in 2001 along Fox Creek in the White River Hills of extreme southwestern Missouri.  It was one of several species that I had selectively “cut” and left in situ for a season to allow infestation by wood boring beetles.  I retrieved the wood the following spring and reared five species of longhorned beetles (family Cerambycidae) from the dead branches, including Astyleiopus variegatus, Hyperplatys maculata, Leptostylus transversus, Lepturges angulatus, and the prize – the very uncommonly encountered Lepturges regularis. All of these represented new larval host records; however, it was not until after I published those records (MacRae and Rice 2007) that I realized the plant itself was not known by Steyermark (1963) to occur naturally outside of the southeastern Ozark Highlands.

Speaking of early spring flowers, many such delights can be found at Berry Go Round #27 which is now up at Mary Farmer’s A Neotropical Savanna. It’s not just spring ephemerals, however, as another Missouri blogger and I show that winter has it’s own botanical charms. Stop by and enjoy the feast!

REFERENCES:

MacRae, T. C. and M. E. Rice. 2007. Distributional and biological observations on North American Cerambycidae (Coleoptera). The Coleopterists Bulletin 61(2):227–263.

Steyermark, J. A. 1963. Flora of Missouri.  The Iowa State University Press, Ames, 1728 pp.

Copyright © Ted C. MacRae 2010

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North America’s second-rarest pine

/ Ted C. MacRae / 13 Comments

Jeffrey (L) and Washoe (R) pines at Galena Creek Park

During last year’s trip to Lake Tahoe, I made it a goal to find all of the 11 conifer species occurring naturally in the Lake Tahoe Basin.  It took some effort, some good references (Arno 1973, Graf 1999, Lanner 1999, and Peterson 1975), and the help of an especially knowledgeable associate at the U.S.D.A. Forest Service headquarters in South Lake Tahoe, but I succeeded in my quest and later wrote two posts covering the Lake Tahoe conifers (Trees of Lake Tahoe – The Pines, Trees of Lake Tahoe – The “Other” Conifers).  In the first of the posts covering the six species of pines, I added the following footnote:

Two additional species of pine – Washoe pine (Pinus washoensis) and single-leaf pinyon pine (P. monophylla) – are often treated as occurring in the Lake Tahoe area. However, they are of sporadic occurrence on the eastern slopes of Mount Rose, and thus do not occur within the Tahoe Basin proper.

Of these, I am quite familiar with single-leaf pinyon pine.  Widespread on isolated mountain ranges throughout the Great Basin into eastern and southern California and Baja California Norte, I have encountered it during many of my field trips out west and reared a number of buprestid species from its tough, scrubby branches (including 2 specimens of the rarely encountered Phaenops piniedulis).  The other species, Washoe pine, was a new one on me, and it is, in fact, the second-rarest species of pine in all of North America (Torrey pine, Pinus torreyana, being the rarest).  Well, that was all it took to make me commit to finding this species on this year’s return to Lake Tahoe.

Washoe pine cones surround a larger Jeffrey pine cone.

Washoe pine grows only in a few locations, primarily in northern California with the best stands found in the Warner Mountains in Modoc County.  In the Tahoe area, Washoe pine grows only on the eastern slope of Mt. Rose in Nevada, where it is limited to the upper reaches of Galena Creek (Graf 1999, Lanner 1999).  It is apparently very similar to Jeffrey pine (P. jeffreyi) – the most common pine in the Tahoe area – but seems to be more closely related to ponderosa pine (P. ponderosa), which occurs at lower elevations and barely makes it up to the Tahoe area (some authorities even question the distinctiveness of this species, instead considering it a high elevation variety of ponderosa pine).  All three species are 3-needled and grow into tall, pyramidal trees with widely spaced horizontal branches.  Like ponderosa pine, the bark of mature trees forms broad yellowish plates separated by black fissures (the bark of Jeffrey pine is often more reddish with plate more narrowly separated).  The resin of Washoe pine is also chemically similar to that of ponderosa pine, both of which differ from the heptane-producing resin of Jeffrey pine.  However, Washoe pine cones more closely resemble those of Jeffrey pine, being somewhat smaller but sharing the “inward-curved” prickles on the scale tips that make them easy to handle (those of ponderosa pine point outwards, making them very prickly to handle).

Ponderosa (L) and Washoe (R) pine cones. Note smaller size and outward-pointing spines of ponderosa pine cone.

Jeffrey (L) and Washoe (R) pine cones. Both have inward-pointing spines, but Washoe pine cone is smaller and more loosely built.

None of my references had any specific locality information for Washoe pine beyond what I’ve stated above, but a little bit of Google snooping through conservation action plan documents revealed that the species occurred at Galena Creek Park, so early in the morning daughter Madison and I made the one-hour drive from South Lake Tahoe to the park.  Arriving at the park, I was disappointed to find nobody manning the headquarters, no maps in the park information board – indeed, no information whatsoever about the occurrence of Washoe pine within the park and where it might be found.  The only clue that there was something special about the pines at this place were the wooden signs around the parking and picnic areas stating “Collection of pine cones prohibited.” I reasoned that it would be very difficult to distinguish the species by its needles, bark, or form, but that the pine cones should be easier to distinguish. I also had no idea whether the pines would occur close to the parking area or if we would need to hike into the area to find them.  So, we just began picking up pine cones.  For a time, all of the pine cones seemed to be typical Jeffrey pine (abundant in the area) with an occasional ponderosa pine (just making up the 6,200′ of elevation in this area).  Ever concerned that I might be missing a subtle difference, I studied each “Jeffrey” pine cone carefully looking for any reason to regard it as truely smaller than normal.  Within about 15 minutes, however, we found it!  Picking up the pine cone, it had the compact build and inward-pointing spines of a Jeffrey pine, but it was smaller and a little more loosely built.  I looked at the trees above and could see no difference from what I would expect for a Jeffrey pine.  Further looking revealed numerous cones of the same type – each tree we found them under was otherwise indistinguishable from Jeffrey pine (at least to this eastern U.S.-based wannabe botanist).  Nevertheless, it was clear that we had found Washoe pine, and that it was quite abundant within this small watershed that we were exploring.  Jeffrey pine was also common in the watershed, and an occasional ponderosa pine could be found.  I took photos of mature individuals of each of the three species, identified conclusively by way of the cones found underneath them, to show how similar in appearance the three species are.

Pinus ponderosa

Pinus jeffreyi

Pinus washoensis

Madison and I later hiked out of the watershed into the higher elevations of Mt. Rose (from where these ants were photographed) – we noticed that almost immediately upon hiking out of the watershed the Washoe and ponderosa pines disappeared, and only Jeffrey pines were seen.  Although I have seen it many times before, I was still hoping to see single-leaf pinyon pine, but none were seen.

REFERENCES:

Arno, S. F. 1973. Discovering Sierra Trees. Yosemite Association, Yosemite National Park, California, 89 pp.

Graf, M.  1999. Plants of the Tahoe Basin.  Flowering Plants, Trees, and Ferns.  A Photographic Guide. California Native Plant Society Press, Berkeley, 308 pp.

Lanner, R. M.  1999. Conifers of California.  Cachuma Press, Los Olivos, California, 274 pp.

Peterson, P. V., and P. V. Peterson, Jr.  1975. Native Trees of the Sierra Nevada.  University of California Press, Berkeley, 147 pp.

Copyright © Ted C. MacRae 2010

Winter Botany Quiz #6 – answers and a checklist

/ Ted C. MacRae / 7 Comments

I thought yesterday’s Winter Botany Quiz #6 would be a fairly difficult, and given the apparent difficulty of my previous quizes (Pismire Puzzle and Tuesday Teaser) I thought I’d give readers a break this week and narrow down the location to the Lake Tahoe area. Despite publishing in the dead of night, it took only 31 minutes for Peter Yeeles to swoop down and correctly name the family, genus, species, and function for the structure pictured. His only lapsus regarded the terminology used for the name of the structure itself, leaving the door open for James Trager to snag some scrap points. The plant is, of course, Cercocarpus ledifolius (curl-leaf mountain mahogany) in the family Rosaceae, and the structures pictured above and in the previous post are the stigmas of the flowers persisting as wind-assisted dispersal structures for the fruit. “Cercocarpus” is, in fact, derived from the Greek words for “tailed” and “fruit”, whose numerous erect hairs give the plant in a silvery sheen late in the growing season.

Why was I interested in this plant? It was one of the few tree species occurring in the Lake Tahoe Basin that I wasn’t able to find for last year’s 3-part series, Trees of Lake Tahoe (including The Pines, The “Other” Conifers, and The Deciduous Trees).  Widespread in the mountainous west (and barely qualifying as a tree), its occurrence in the Tahoe Basin is more sporadic.  Better stands are found outside the basin proper on the dry eastern flank of the Sierra Nevada (Graf 1999), and indeed these plants were photographed at ~6,500 feet on the eastern slopes of Mt. Rose.

My real interest in Cercocarpus, however, is as a favored host plant for species of jewel beetles (family Buprestidae).  About two dozen species of these beetles have been associated with Cercocarpus spp. in North America, nine of which have been confirmed as breeding within dead branches of these plants and five having been associated with no other plant.  I’ve collected a number of these species myself, particularly in the San Gabriel and Santa Rosa Mountains of southern California and the Chisos Moutains of Big Bend National Park in Texas, including Polycesta cazieri, Chrysobothris piuta, and paratype specimens of Acmaeodera rubrocuprea. I thought it might be of interest to any readers who might collect these insects to present a checklist of Buprestidae associated with Cercocarpus in North America (see appendix below).

REFERENCE:

Graf, M. 1999. Plants of the Tahoe Basin. Flowering Plants, Trees, and Ferns. A Photographic Guide. California Native Plant Society Press, Berkeley, 308 pp.

Checklist of North American Buprestidae associated with Cercocarpus

(Bold indicates species that have been reared from Cercocarpus.  An asterisk indicates species that have been associated exclusively with Cercocarpus).
– Acmaeodera (s. str.) angelica Fall
– Acmaeodera (s. str.) connexa LeConte
– Acmaeodera (s. str.) dolorosa dolorosa Fall
– Acmaeodera (s. str.) idahoensis Barr
– Acmaeodera (s. str.) mariposa mariposa Horn
– Acmaeodera (s. str.) mariposa dohrni Horn
– Acmaeodera (s. str.) nelsoni Barr
– Acmaeodera (s. str.) nexa Fall
– Acmaeodera (s. str.) plagiaticauda Horn
– Acmaeodera (s. str.) pubiventris lanata Horn
– Acmaeodera (s. str.) rubrocuprea Westcott & Nelson*
– Acmaeodera (s. str.) vandykei Fall
– Acmaeodera (s. str.) variegata LeConte
– Acmaeodera (Squamodera) vanduzeei (Van Dyke)
– Anthaxia (Haplanthaxia) caseyi sublaevis Van Dyke
– Anthaxia (Melanthaxia) porella Barr*
– Anthaxia (Melanthaxia) simiola Casey*
– Chrysobothris bisinuata Chamberlin*
– Chrysobothris mali Horn
– Chrysobothris piuta Wickham
– Chrysobothris purpureovittata purpureovittata Horn
– Chrysobothris purpureovittata cercocarpi Westcott & Nelson*
– Dicerca (s. str.) hornii hornii Crotch
– Polycesta (Tularensia) californica LeConte
– Polycesta (Tularensia) cazieri Barr

Copyright © Ted C. MacRae 2010

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Winter Botany Quiz #6

/ Ted C. MacRae / 7 Comments

This photo was taken during my March trip to Lake Tahoe.  Can you identify the plant (family, genus, species), the structure shown, and its function?  Answer and more photos tomorrow.

© Ted C. MacRae 2010

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Friday Flower – Ozark Witch Hazel

/ Ted C. MacRae / 22 Comments

Spring is beginning its “march” across the nation, and in typical fashion the month started out with the promise of pleasant weather but is throwing a few tantrums before giving way to April. For most folks in the lower Midwest, spring began a week or so ago when daffodils began popping up from nowhere and dotting the suburban and semirural landscapes with their yellow smiles. Forsythia are also set to burst forth, their appearance temporarily put on hold by this latest cold/wet snap, but when they do most people here will be satisfied that spring has finally come. For me, spring comes much earlier, and it’s not planted ornamentals that mark its beginning, but native trees.  Silver maples (Acer saccharinum) and American elms (Ulmus americana) are first, bursting open in the very first warm days of early March.  These are followed by the sugar maples (A. saccharum) and red maples (A. rubrum) that are in full bloom now, which will themselves give way to the redbuds (Cercis canadensis) and serviceberrys (Amelanchier arborea) that will close out the month before flowering dogwood (Cornus florida) dominates the area’s understories in April.

There is one tree in this part of the country, however, that shows its amazing blooms in January and February while winter’s grip is still strong.  Ozark witch hazel (Hamamelis vernalis) is restricted to the Ozark Highlands of Missouri and Arkansas, where it grows along the rocky creeks and streams that dissect this ancient landscape.  I have long wanted to see its striking blooms, but despite my many wintertime hikes throughout the Ozarks, I have never found myself in the right place at the right time – until a few weeks ago when I hiked the Mina Sauk Trail at Taum Sauk Mountain State Park.  I found these plants growing below Mina Sauk Falls and along Taum Sauk Creek below, and even though it was the first weekend of March (and the very first warm day of the season), many of the plants had already passed their peak bloom.  Fortunately, I was able to find these several plants with flowers still in good shape.

There is only one other species in the genus – eastern witch hazel (Hamamelis virginiana).  Although distributed widely across eastern North America, it is restricted in Missouri to these same St. Francois Mountains where I saw H. vernalis.  The two species are very similar by the characteristics of their foliage but can be easily distinguished by floral characters.  Hamamelis virginiana blooms in fall rather than winter, and its flowers, while nearly twice the size, rarely show the amount of red on the inner calyx that is seen in this species.  Hamamelis vernalis flowers are also quite fragrant, having what has been described as a “vanilla” scent.  The photographs here show the rather unusual color range of the flowers of this species, which can vary from orange to deep red to deep yellow.  I suspect that flower color also changes with age, in that petals are initially deep red and later fade to yellow, as in the photo below.  It’s difficult to explain why H . vernalis is restricted to the Ozark Highlands while H. virginiana occurs so broadly, but the Ozarks are a well-known refugium for a number of other plants and animals, especially Ice Age relicts.

Sitting on a rhyolite ledge overlooking Taum Sauk Creek as I ate lunch, I wondered about the pollination biology of a plant that flowers during winter.  It was a warm day – certainly an unusual occurrence during the period in which this plant flowers – and even still it was too early in the season for a lot of insect activity.  I watched one of the nearby plants as I ate to see what insects came to the flowers, and for a time all I saw were a couple of European honey bees.  Clearly, the plant did not evolve in association with this now ubiquitous insect.  I continued watching, and at last I saw a native insect visiting the flowers – a large species of hover fly (family Syrphidae), perhaps something in the genus Helophilus.  After taking a few more photographs (unfortunately, none of the fly), another of the same species visited the plant.  Flies in general are famous for appearing during warm days in winter, and I wonder if the unusually extended bloom period of this species is intended to take advantage of those few, unpredictable days during winter when temperatures are sufficient for flies to become active.

Photo Details: Canon 100mm macro lens on Canon EOS 50D
Photo 1: ISO 100, 1/200 sec, f/11, MT-24EX flash w/ Sto-Fen-Puffer diffusers.
Photo 2: ISO 200, 1/200 sec, f/5.6, ambient light.
Photo 3: ISO 100, 1/60 sec, f/9, flash w/o diffusers.
Photo 4: ISO 200, 1/250 sec, f/5.6, ambient light.

Copyright © Ted C. MacRae 2010

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Clubmoss along the Ozark Trail

/ Ted C. MacRae / 19 Comments

It has been a long, hard winter – one of the toughest I can remember during my years here in Missouri in terms of amount and frequency of precipitation and persistent cold temperatures. Tough winters, however, are no deterrent to my favorite wintertime activity – hiking. I’ve mentioned several times the goal of my friend Rich and I to hike all 350 miles of the Ozark Trail.  We’re at ~250 miles now (more than 2/3 done), thanks to the two 10-mile stretches of the Wappapello Section that we did on the days after Thanksgiving and New Year’s. 

Hiking these trails is an opportunity to imagine the Ozark Highlands in their wild, pre-settlement state – expansive hardwood forests covering miles and miles of rugged up-and-down terrain.  Of course, try as I might to pretend otherwise, the Ozarks have changed, and evidence of man’s pervasive presence are everywhere.  Some are overt, such as this mass grave of domestic cattle, dumped by their former owner for others to worry about when disease prevented them from realizing their economic potential.  Others are much more subtle, but to the discriminating naturalist they are everywhere – even in the most pristine-looking of areas.  A cedar-choked glade here, it’s rich, tawny, native warm-season grasses pushed the margins and interspaces; a monotonous, stunted black oak forest there, sprigs of herbaceous plants giving a hint of the diverse understory just waiting for a fire to bring back the more open woodland it needs to thrive.  Settlement has brought with it not only direct impacts to the land, but also changes in its ecology and vegetational character.  Once a fire-mediated landscape with shifting mosaics of bald ridges, grassy woodlands, and riparian forests, a century of logging, grazing, and fire suppression have turned much of the Ozark Highlands into homogenous stands of oak with depauperate mid- and understories.

While loss of diversity has been the overwhelming trend in response to settlement, additions to the state’s flora are also being seen.  The Wappapello Section is the southeasternmost of all the Ozark Trail sections, lying almost entirely in Wayne County, and as we traversed the rugged terrain north to Sam A. Baker State Park, we encountered this most unusual of plants – a clubmoss.  Since they are vascular plants, clubmosses are not really moss (which are non-vascular).  Clubmosses are not flowering plants either, nor do they even produce seeds, reproducing instead by spores – just like ferns, horsetails, and other ‘primitive’ (sorry, Alex!) vascular plants.  Practicing botanists include them in a group known as “fern allies”, meaning that they are not ferns (ferns have multiple branching veins in their delicate fronds, while clubmosses have a single vein in their small, scale-like leaves), but they are somewhat like them.

This particular clubmoss belongs to the genus Lycopodium, or ground cedars – the name obviously derived from the resemblance of their foliage to various gymnospermous plants known as cedars (though completely unrelated) but growing very low to the ground. There are three species of Lycopodium in Missouri (Yatskievych 1999), all confined to the Ozark Highlands and all considered species of conservation concern due to their rarity in the state (Missouri Natural Heritage Program 2010).  Two of these species are highly restricted (designated S1 for “critically imperiled”), boreal species occurring only on moist sandstone bluffs in Ste. Genevieve County as Pleistocene relicts – holdovers from a time when glaciers advanced to within about 50 miles to the north and cool, wet conditions prevailed throughout the rest of the state.  The third species, shown here, is Lycopodium digitatum.  Although more widespread in the cool forests of the northeastern U.S. and Canada, it is apparently expanding its range and was first found in Missouri in 1993.  While still considered uncommon (and accordingly designated S2, or “imperiled”), its range has since expanded to a core of several southeastern Missouri Ozark counties that include Carter, Iron, Madison, Reynolds, and Wayne Counties (Doolen and Doolen 2008).  We found this colony at the base of a moist wooded slope amongst an invading stand of Juniperus virginiana (ironically, called “cedars” by local residents).

“Running ground cedar” has been used as a common name for L. digitatum, most likely due to its habit of spreading by rhizomes – or “runners” – along the soil surface.  From a distance, the spore-producing strobili stood out in bright yellow contrast to the dark glossy green foliage that carpeted the ground – itself in stark contrast with the surrounding brown leaf litter.  It is these club-like strobili from which the common name “clubmoss” is derived, and from a distance of 20 m away I knew instantly that this was something unusual and worthy of investigation.  Despite the gray November skies and cool temperatures, the strobili were actively shedding spores – clouds of yellow dust swirling briefly with each knock of the finger before dissapating into the air.

Hundreds of millions of years ago, the Carboniferous earth was covered with vast forests of giant clubmosses – extinct relatives of this species that soared to heights of one hundred feet. These giants eventually gave way to new kinds of plants – first the seed-bearing conifers, and later the flowering angiosperms. The giant clubmosses are gone, but their descendents have survived the vastness of time, represented today by these humble, diminutive forms – extant members of an ancient group hiding in the nooks and crannies of the modern flora. I don’t know whether the recent appearance of L. digitatum in the Ozark Highlands is a result of the anthropogenic changes brought upon the area in recent years, but given its ancient, relictual qualities, it is one change in the flora of Missouri that I do not mind.

REFERENCES:

Doolen, W. and C. Doolen.  2008.  Clubmoss wonders in southeast Missouri.  Perennis, Newsletter of the S.E. Missouri Native Plant Society 1(4):1–2.

Missouri Natural Heritage Program.  2010.  Missouri Species and Communities of Conservation Concern Checklist.  Missouri Department of Conservation, Jefferson City, Missouri, 53 pp.

Yatskievych, G. 1999. Steyermark’s Flora of Missouri, Volume 1. Missouri Department of Conservation, Jefferson City, 991 pp.

Copyright © Ted C. MacRae 2010

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