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Archive for the ‘Smokies Natural History’ Category

A double-petaled Large-flowered Trillium

No one knew what to expect for the Spring Wildflower Pilgrimage this year.  It was scheduled two weeks earlier than the traditional timing (April 11-15), park officials put several restrictions on trails and program size, and the wildfire last November left sections of the park charred and scarred.  The week also corresponded with one of many spring breaks and the Easter holiday.

Traffic and parking proved the only real negatives.  It might as well have been the height of summer in Gatlinburg.  Pilgrimage goers have never seen this town so crowded during the work week.  We think curiosity about the devastating fire and a desire to help the city recover drove the exceptional visitation.

Silverbell

Every year the wildflower status for Pilgrimage week increasingly becomes a roll of the dice.  2017 turned out to be a jackpot year.  Trees were barely leafing out at lower elevations, most ferns were still rolled in tight crosiers, but the herbaceous wildflowers were going nuts.  A concentrated flush of flowering placed remnant Bloodroot, Liverleaf, Trout Lily, Wood Anemone, and Fringed Phacelia in direct competition with emerging Crested Iris, Fire Pink, Yellow Trillium, Wild Geranium, and Robin’s Plantain.  Both Silverbell and Flowering Dogwood were showy, and a few Serviceberries joined in for good measure.  It was simply spectacular.

Yellow Trillium whose flower parts have reverted to leaves.

Some unique sightings added to the flora fun.  During our hikes, we saw a Large-flowered Trillium (Trillium grandiflorum) with two sets of petals and a cluster of Yellow Trillium (Trillium luteum) whose floral parts had all reverted to mottled green leaves.

The weather was unseasonably warm, daily highs hovering near 80º, and very dry.  No April showers for days is unusual.  These conditions guarantee the colorful parade of flowers will pass quickly.

Burned ridges from the Chimney Tops 2 Fire viewed from the Carlos Campbell Overlook on Feb. 13, 2017

Fire ecology became the default theme of this year’s Pilgrimage.  Officials with the park and southeastern universities helped everyone understand the role fire plays in the natural landscape.  We hiked part of the bleak, blackened forest and witnessed the first stirrings of recovery.  Rob Klein, Fire Ecologist for the park, gave a presentation on fire, including pictures of the most severely burned areas.

Same view April 12, 2017

Chimney Tops 2 fire (the second fire in that area in 2016) started Nov. 23 on the Chimney Tops Trail, initated by two teenagers striking matches in the drought-plagued forest.  It was a slow fire creeping through the underbrush in an area of steep and difficult terrain, nearly impossible to access and fight effectively.  Park officials watched it carefully.  By Nov. 26, it had impacted only 40 acres.  Two days later, an approaching storm system arrived earlier than expected and brought winds much stronger than predicted into the area, generating a phenomenon known as mountain wave winds.

Right hand ridge from Balsam Point, Feb. 13

The National Oceanic and Atmospheric Administration describes this wind pattern: “Mountain waves develop on the lee, or downwind, side of mountains.  These waves are generated when strong winds flowing toward mountains in a generally perpendicular fashion are raised up over the mountains.  As the winds rise, they may encounter a strong inversion or stable air barrier over the mountains that causes the winds to be redirected toward the surface.  Instead of reaching back down to earth, the winds continue in an up-and-down wave-like pattern downwind of the mountains that may extend for hundreds of miles.”

Close-up view of ridge showing effects of a high severity fire

These mountain wave winds, hitting velocities of 80 to 100 mph, struck November 28 and within hours the 40-acre fire mushroomed into a 17,000-acre conflagration that destroyed hundreds of homes and businesses in Gatlinburg and sparked electrical fires from downed trees as far away as Cosby.  Fourteen people lost their lives.

Dead and downed wood smouldered on the Cove Hardwood Trail.

The fire burned 11,000 acres within the park according to Klein.  On half of those acres, the fire was low severity, removing the litter layer and a bit of the underlying duff.  It left evergreen shrub foliage brown on lower branches and green at the top.  A more open forest understory results, which will rebound within 5 to 10 years.  Cove hardwood communities escaped with little to no fire impact.  These moister, protected environments are less likely to support a hot fire even in drought.  The Cove Hardwood Trail at Chimneys Picnic Area, appears mostly untouched except for a few old logs and stumps that smoldered and charred.

Moderately severe fire on Baskins Creek Trail

Twenty-five percent of the burned acres experienced a moderately severe fire.  Litter and most of the duff was consumed.  Shrubs were completely browned to burnt, perhaps compromising the ability of rhododendrons to resprout.  Tree bark and pine needles were scorched.  Moderate fires open the forest and produce changes to its structure and composition.

Areas of high severity fire occurred primarily in the montane oak, pine, and heath communities found along ridges, approximately 1,000 acres.  Litter and duff were completely consumed, shrubs killed, and trees burned top to bottom.  Klein’s photo reveals a bare and blackened landscape with broken stubs of tree trunks like burnt matchsticks.

Bullhead and the severely burned heath bald (far right)

The Carlos C. Campbell Overlook on Highway 441 gives visitors a overall view of seven different community types in the park, and the intensely scorched sections correspond perfectly to the oak, pine, and heath ridges noted on the interpretive signage.  Some people have noted the right ridge line fire scar’s resemblance to an angel.

In the next few years, these areas of high severity will become dense with native herbaceous plants like fireweed and other weedy species that dominate highly disturbed wild lands.  Pine seedlings will germinate and carpet the landscape in a “dog-hair thicket” of saplings within 5 to 10 years.

Open and closed Table Mountain Pine cones

This rebirth has already begun.  The large cones of Table Mountain Pine (Pinus pungens), an Appalachian endemic, are serotinus.  A resinous substance seals the scales shut and only loosens with higher temperatures from solar radiation or the heat of fire.  Three days after the fire on Dec. 1, park officials documented pine seeds “raining” down.  On March 2, they noted the first sprout, and by April 13, numerous sprouts could be found.

Open cones of Table Mountain Pine on Baskins Creek

These ridge communities of oaks, pines, and members of the heath family are fire adapted, tolerating fires every 5 to 15 years on average.  Thicker bark, an ability to sprout from the stump, and the need for an open canopy to germinate and grow allow them to survive recurring fires.  In turn, these fires ensure regeneration of the species, maintenance of wildlife habitat, and reduction of fuel loads.  This last benefit prevents future fires from becoming too destructive and disruptive to the community.

In fire adapted communities, lack of fire can prove just as disruptive, leading to species decline and the possibility of severe canopy fires.  Along Baskins Creek Trail, the fire was of moderate severity in the Table Mountain Pine stand.  Cones on the trees are open, and pine seedlings are sprouting in the open understory.

Table Mountain Pine seedling

Forests may look very different in the aftermath of a big fire, but they begin their march back almost immediately.  The same is true for Gatlinburg.  Most fire damaged properties have been cleaned up, and construction is booming.  The forests and the town are well on their way to recovery.

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Multiflora Rose cultivar locked in a battle with Chinese Yam

Multiflora Rose cultivar locked in a battle with Chinese Yam

Several non-native plant species keep company with the sagging structures on Society Hill in Elkmont. Orange flags of Tawny Daylily wave at visitors in June and July. Some plants, like daffodils and daylilies, are a sure sign of homesteads. I’ve seen Trifoliate Orange (Poncirus trifoliata), a beastly looking thing, growing on Little River Trail in front of an old cabin. Many of these introduced plants aren’t a problem in the forest, but other species, like English Ivy or Japanese Spiraea, can invade natural areas and displace native plants. Brought in by settlers and/or resort residents, it’s touchy business for the park to tread that fine line between preserving the past and protecting the forest. Some plants won’t stay put and must be removed. Less threatening historic species get a cultural pass.

At the old Jakes Creek trailhead location past the cabins, a pink, fully double garden rose bears the fringed leaf-petiole stipules of Multiflora Rose. [That fringed stipule is clearly visible in the Avent Cabin rose photo from the previous post.] The double rose variety also grows along a stretch of Little River Trail. Park staff target the straight species for removal because of its highly invasive nature, but this unidentified cultivated variety doesn’t exhibit such aggressive tendencies. Kristine Johnson, Supervisory Forester for the park explains, “I don’t like to kill anything without a definite ID, and I’m not able to reliably identify the rose cultivars.” She would welcome assistance from a knowledgeable rosarian.

Coltsfoot foliage, a patch now long gone from Elkmont!

Coltsfoot foliage, a patch now long gone from Elkmont!

“There is a measure of caution in respect for those whose homesite it was (‘granny’s rose!’) as well as the possibility of a long lost variety someone may treasure.” However, if it shows signs of spreading or reverting to the multiflora rootstock, she shows no mercy. Japanese Spiraea got no mercy in 2011. I spotted it flowering at the Jakes Creek parking lot, and Kris had staff there within a day to kill it.

Chinese Yam (Dioscorea oppositifolia), often grown as food for its starchy roots, twines its narrow, heart-shaped leaves through the Jakes Creek rose bush obscuring much of the latter’s foliage. The sight of two invasive plants locked in battle always elicits a smile, hoping each will kill the other! Due to its twining nature, Chinese Yam is difficult to treat without damaging non-target neighboring plants. Fortunately, a fungus helps out. According to Kris, “Over the 20 or so years I’ve seen it here, it seems to die out in shady areas from a foliar fungal disease but remains a problem in disturbed sites like roadsides until a wet season does it in.” A toast to Smoky Mountain rain!

One interloper on Jakes Creek has nothing to do with the past. A small patch of Coltsfoot (Tussilago farfara) next to the road likely hitchhiked on gravel during road work. It has a sunny little Dandelion-like flower but is the very devil to eradicate. Kris directed park staff to stomp on that patch with vengeance. Good riddance.

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Unknown fly (dead?) on a Buttercup

Dung fly victim of ‘The Insect Destroyer’

In May 2012, while hiking the Appalachian Trail through the park, I photographed several flies at Double Spring Shelter. One had apparently died face down in a buttercup. Others were clinging to unfurling beech leaves. All of them had swollen abdomens striped white and brown (or pinkish and gray) on the upper side and white (or pink) underneath and were pitched at a strange angle with wings and legs spread, abdomens raised.  (June 2012 Archive, AT Day Four and AT Day Five)

When writing those blog posts, I could neither determine the species of fly nor discover an explanation for their behavior. In December 2013, 19 months after this unusual sighting, I found the answer to both mysteries quite by accident.

I have been researching the Kingdom Eumycota (fungi) for the Tennessee Naturalist Program. I serve on their board and teach their class on plants and fungi at Owl’s Hill Nature Sanctuary near Nashville. TNP is developing detailed curriculum study guides for each class topic, and I am writing the guide for “Forbs, Ferns, Fungi, and More.”

Flies on Beech leaves

more victims

The fungi kingdom is still rather new (comparatively speaking — fungi used to be part of the plant kingdom) and is undergoing significant reorganization as more fungi are identified and classified, especially with DNA studies. This has wreaked havoc on the kingdom’s phyla (main classification ranks), and I was trying to piece together the current picture, particularly with Zygomycota. Fungi in this phylum are quite diverse and include parasitoids, organisms that live part or most of their lives within a host and usually kill that host.

A few well-known species of parasitoid fungi are in the genus Entomophthora, a Latin name that means “insect destroyer.” Sticky spores of these fungi float through the air, and when one reaches a fly, it adheres to the body, germinates, and produces a hypha that penetrates the fly (usually through a soft segment membrane), and begins to grow throughout the fly’s body. It grows so much, the dark abdominal segments spread apart exposing light colored membranes in between and imparting a striped appearance. Then comes the creepy part.

The fungus invades the fly’s brain and alters its behavior. The fly crawls up to a high place just before it dies, cements its proboscis to a surface, flares open its wings, stretches its hind legs, and raises its abdomen up and out. This bizarre posture of death optimizes the chances for spores to infect new hosts. When the fly dies, sporangia burst through the segments and abdominal wall, forcibly discharging spores up to 3/4 inch away, a decent distance for a microscopic spore. These spores may form a whitish halo on and around the fly. The timing of all this often occurs in the hours before midnight, when the humidity is higher and environmental conditions are most favorable for spore production.

Healthy looking fly on Beech leaf

a dung fly on its way out

One final fungus note: Should this infection and death occur late in the year, spores are not produced. The dead fly drops to the ground and so-called “resting spores” develop in the body to overwinter. In spring, the spores are discharged to begin a new year of infection cycles.

With the fungus identified, I begin researching the host flies. It only infects adults and has been found in several fly families, including common house flies, hover or flower flies, dung flies, flesh flies, blow flies, and tachinid flies, plus other invertebrates such as moths and aphids. There are several species of Entomophthora, each tending to infect certain insect species. These fungi are being examined as a biological control for pest species like house flies and gypsy moths.

After extensive review of the fly families frequently targeted by Entomophthora on BugGuide.net, I’m fairly certain the flies pictured here are in the family Scathophagidae or dung flies. The wing markings and leg hairs are a solid match.

Isn’t nature remarkable? …and sometimes scary? …and isn’t it a fantastic feeling to finally solve a year-and-a-half-old puzzle?

[Primary source: The Kingdom Fungi: the Biology of Mushrooms, Molds, and Lichens by Steven L. Stephenson, Timber Press, 2010.]

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Kate and I at Todaiji Temple in Nara, Japan

Kate and I at Todaiji Temple in Nara, Japan

I have studied the flora of my home state, Tennessee, for the past 15 years. Initially, these efforts focused on those plants suited for gardens and managed landscapes. In recent years, a heightened interest in ecology led me toward the naturalist’s perspective to include all plants and other organisms functioning as a biological system within their physical environment. This view guides my trail accounts.

I recently spent two weeks in Japan to see my daughter Kate who lives there. I had last visited in March 2010 and enjoyed the stunning display of cherry blossoms (sakura). This trip was timed to see fall color. Kate’s itinerary for us, including five days in Kyoto, a day trip to Nara, and an overnight trek to the mountains of Nikko, focused on the heart and soul of Japan in autumn.

These may seem two disparate paragraphs, yet they share a common bond far beyond the author, a bond that many theorize dates back to the Tertiary up to 65 million years ago. For the past 260 years, botanists have noted certain plants found in both eastern Asia and eastern North America. Botanic explorations around the globe revealed similar plant genera and species, similar ecological niches, and a similar climate in these two continental regions. Floristic similarities were also found in parts of Europe and western North America plus a few other scattered locales.

It is snowing at Ryuzu, the 'Dragon Waterfall' near Nikko

It is snowing at Ryuzu, the ‘Dragon Waterfall’ near Nikko

When the same or closely related organisms are found in two or more widely separated regions it is referred to as a disjunct distribution. There are many examples large and small of interrupted ranges, but the Asia/North America disjunct was the first on a large scale to be recognized and has attracted the interest of scientific notables from Carolus Linnaeus (the father of modern scientific classification) to Asa Gray (Manual of Botany) and Charles Darwin.

Darwin corresponded extensively with Gray and encouraged him to further explore this floristic affinity between the continents. Darwin was nearing publication of On the Origin of Species by Means of Natural Selection (Nov. 1859), presenting his theory that species populations evolve over time. In the same year, Gray published a paper on the “diagnostic characters” of plants collected from Japan by Charles Wright in which he records “observations upon the relations of the Japanese flora to that of North America, and of other parts of the Northern Temperate Zone.”

Kanmangafuchi Abyss in Nikko

Kanmangafuchi Abyss in Nikko

None of his predecessors had postulated an explanation for such long distance “relations.” Gray did. He used plant fossils, current theories of geological history, and Darwin’s ideas of evolution and common descent to support the concept of a previously extensive flora now disrupted. (Boufford and Spongberg 1983) Twenty years later European botanist Adolf Engler, also using fossil evidence, proposed a wide ranging flora during the Tertiary Period of the Cenozoic Era.

Kanmangafuchi Abyss in Nikko

Kanmangafuchi Abyss in Nikko

By the start of the Tertiary, seed-bearing plants (angiosperms) had become the dominant terrestrial plant form. Throughout this period spanning 63 million years, continents inched northward and the climate cooled from uniformly warm and tropical to seasonally cool and temperate. Migration pathways over exposed land bridges (Bering to Asia and North Atlantic to Europe) fragmented and disappeared. Continental uplift and development of polar ice caused an epicontinental sea across the North American plains and the Mississippi Embayment along the gulf coast to recede. Broadleaf evergreens retreated southward, deciduous hardwoods (once restricted to high elevations) expanded rapidly to take their place, and conifers colonized high latitudes and upper elevations.

Kiyomizu-dera Temple in Kyoto

Kiyomizu-dera Temple in Kyoto

Scientists have theorized that as these changes gradually evolved, a broad belt encircling the northern latitudes favored the development of a rich and widespread flora dubbed the Arcto-Tertiary Geoflora. This flora reached its fullest expression in the Miocene Epoch when the Temperate Broadleaf Deciduous Forest (TBDF) was king. Further geologic and climatic changes would introduce barriers of separation, reduce area coverage of the TBDF, precipitate extinctions, and initiate evolution of distinct species within genera.

View from Nanzenji Gate, Kyoto

View from Nanzenji Gate, Kyoto

Asia and Europe became isolated from North America. The Rocky Mountains rose creating a rain shadow that changed the central plains from forest to prairie and isolating the continent’s western portion from the east. Quaternary glacial advances struck areas unevenly. Europe’s flora was hit hard by extinctions, North America’s was likely reduced particularly in the northwest, and Asia’s escaped much harm.

This Viburnum in the mountains of Nikko is remarkably similar to our Hobblebush (V. lantanoides).

When early botanists first noticed these continental-scaled plant disjuncts, they identified most of the paired plants as the same species. Further study, however, proved the majority to be distinct, though related, species in the same genus or separate but closely related genera in the same family. Ecological research shows that these paired, distinct species typically occupy similar habitats and plant communities in their home ranges. “The similarities of the forests of Japan, central China, and the southern Appalachians in appearance as well as in ecological associations are in many instances so great that a sense of déjà vu is experienced by botanists from one of the regions visiting the other.” (Boufford and Spongberg 1983)

Pawpaw, member of the tropical family Annonaceae, adapted to temperate forests. It is a more primitive flowering tree.

Pawpaw, member of the tropical family Annonaceae, adapted to temperate forests. It is a more primitive flowering tree.

The disjunct species strongly tend toward certain characteristics. (White 1983)
1. With few exceptions, the plants grow in temperate, moist (mesic) forest environments.
2. Most of the species are woody, broadleaf deciduous plants.
3. Herbaceous species are typically perennial, spring blooming, early leafing ephemerals from rhizomes or tubers adapted to life on the shady forest floor.
4. Many of the disjunct plant families are older from an evolutionary standpoint. Their flower structure is more primitive than other existing flowering plants (ranalian complex). These families include Magnoliaceae – Magnolia; Ranunculaceae – Buttercup, Meadow-rue, Liverleaf, Clematis, Black Cohosh, and Dolls Eyes; Annonaceae – Pawpaw; Lauraceae – Sassafras and Spicebush; Calycanthaceae – Sweetshrub; Berberidaceae – Barberry, Blue Cohosh, Umbrella Leaf, May-apple; Menispermaceae – Canada Moonseed; and Nymphaeaceae – Water Lily.

There are only two species of Liriodendron (Tulip Poplar). The other is in China and has larger, deeply lobed leaves and green flowers (no orange).

There are only two species of Liriodendron (Tulip Poplar). The other is in China and has larger, deeply lobed leaves and green flowers (no orange).

Research on disjunct species in the Great Smoky Mountains National Park showed these plants “concentrated in mesic low- to mid-elevation forests.” (White 1983) White noted that these habitats are already richly diverse and the disjunct species increase that community diversity. This temperate forest type, called mixed-mesophytic and known as the “cove” forest in the Smokies, is characterized by greater species richness than any other forest type in temperate climes. The Appalachians and central China are the only areas globally where mixed-mesophytic forests currently exist. (Yih 2012)

Our native Ginseng

Our native Ginseng

Approximately 65 genera have been identified as disjuncts appearing only in eastern Asia and eastern North America. Wofford (1989) listed 46 of them as occurring in the Blue Ridge of Tennessee. The list includes Aletris (Colicroot), Melanthium (Appalachian Bunchflower), Tipularia (Cranefly Orchid), Buckleya (Pirate Bush), Pyrularia (Buffalo Nut), Liriodendron (Tulip Poplar), Adlumia (Allegheny Vine), Astilbe (False Goat’s-beard), Hamamelis (Witch Hazel), Cladrastis (Yellowwood), Pachysandra (Allegheny Spurge), Stewartia (Mountain Camellia), Panax (Ginseng), Pieris (Mountain Fetterbush), Halesia (Silverbell), Campsis (Trumpet Creeper), Phryma (Lopseed), and Mitchella (Partridgeberry).

Silverbell (Halesia) has three species in eastern North America and one species in eastern Asia.

Silverbell (Halesia) has three species in eastern North America and one species in eastern Asia.

For the 26 genera additionally found in western North America, more than 90% occur in Tennessee’s Blue Ridge. (Wofford 1989) These include Tsuga (Hemlock), Clintonia (Bluebead Lily), Disporum [Prosartes] (Nodding Mandarin), Trillium, Calycanthus (Sweetshrub), Dicentra (Dutchman’s Breeches), Aristolochia (Dutchman’s Pipevine), Mitella (Bishop’s Cap), Tiarella (Foamflower), Rubus (Blackberry), Rhus (Sumac), Geranium, Aralia (Devils-walkingstick), Leucothoe (Doghobble), and Menziesia (Minnie Bush).

Our native Pachysandra, Allegheny Spurge

Our native Pachysandra, Allegheny Spurge. There are at least two other species in China and Japan.

Adding Europe to the mix, the four regions share at least 20 genera such as Erythronium (Trout Lily), Veratrum (False Hellebore), Ostrya (Hophornbeam), Clematis, Cimicifuga (Bugbane/Black Cohosh), Hepatica (Liverleaf), Asarum (Ginger), Rhododendron, Philadephus (Mock Orange), Platanus (Sycamore), Waldsteinia (Barren Strawberry), Cercis (Redbud), Staphylea (Bladdernut), and Aesculus (Buckeye). (Wofford 1989)

Western North America and the Southern Appalachians share 150 genera including Xerophyllum (Turkeybeard) and Dirca (Leatherwood). (Wofford 1989) I have photographed so many of these plants during my Smokies hikes!

Allegheny Spurge has mottled winter foliage and very fragrant flowers in early spring.

Allegheny Spurge has mottled winter foliage and very fragrant flowers in early spring.

DNA studies have enabled botanists to more accurately scrutinize the evolutionary development of these plant species (phylogeny), and they are finding a mixed bag of information. It paints a far more complex history that “may have involved multiple historical events at very different geological times in different genera.” (Xiang, Soltis and Soltis, 1998) In some instances, genetic work reveals that paired disjunct species are not as closely related to each other as to other relatives indicating continued species evolution and diversification after separation.

Ginkakuji Temple in Kyoto. Note the large clump of  Miscanthus grass behind the tree on the right. Miscanthus is an invasive plant in North America.

Ginkakuji Temple in Kyoto. Note the large clump of Miscanthus grass behind the tree on the right. Miscanthus is an invasive plant in North America.

Some believe Asia was at or close to the center of origin for flowering plants. It has far richer plant diversity, more genera and species, than eastern North America. Asian temperate forests contain approximately three times as many tree species as similar forests in North America. (Guo 1999) Xiang, Soltis, and Soltis (1998) state “eastern Asia, with its 2,753 genera of seed plants, has a biodiversity far greater than that of eastern North America, which has only 1,230.” They cite the “extreme example” of Lindera (Spicebush) [east Asia has 80 species, eastern North America three] and assert this could be attributed to Asia’s “complex topography…promot[ing] a greater rate of speciation due to the abundance of varied habitats and natural barriers that could allow different populations of a species to evolve separately.”

China’s flora, not extensively explored and cataloged until the late nineteenth and early twentieth centuries, was of particular interest for its diversity of woody species. Botanists were not the only people intrigued with Asia’s botanical riches. Horticulturists, noting the similarities in climate and plants, accurately estimated the likely success for cultivation of Asian species in North America as ornamentals. Charles Sargent, first director of the Arnold Arboretum (Harvard University), raised seeds sent to him from China and pushed for the collection of more specimens including living plants. (Boufford and Spongberg 1983)

Sweet Autumn Clematis, an invasive vine, is the Asian equivalent of our Virgin's Bower. Photo Chris Evans, River to River CWMA, www.insectimages.org

Sweet Autumn Clematis, an invasive vine, is the Asian equivalent of our Virgin’s Bower. Photo Chris Evans, River to River CWMA, http://www.insectimages.org

This climatic, floristic, and ecological affinity has a distinct downside. Asian plants grown in North America may find the local accommodations much to their liking. Freed from evolved competition and predation (insects and disease) back home, their new digs pose little impediment to growth and spread. North American plants, fighting their own battles with native competitors and predators, are quite unused to the foreign competition and have yet to evolve effective means to fight back. Many lose ground to aggressive exotic species which then take over habitats, drastically diminishing diversity. Other organisms dependent on the displaced native species lose too.

Our native Clematis, Virgin's Bower

Our native Clematis, Virgin’s Bower

In Tennessee, 135 species are listed as known or possible exotic invasive plants. Nearly half, 60 species, are native to Asia and the overwhelming majority are woody (trees, shrubs, or vines). Many other species are generally ascribed to “Eurasia.” Among the most serious pest plants, 18 of the 26 species ranked as a Severe Threat in Tennessee are from Asia. Sixty-six species on the invasive list may be found in nurseries for cultivation, and 40 of them are from Asia.

The same pairing of remarkably similar plants occurs with some of the invasive species: Burning Bush (Euonymus alatus) and Hearts-a-bustin’ (E. americanus), Japanese Wisteria (Wisteria floribunda) and American Wisteria (W. frutescens), Japanese Honeysuckle (Lonicera japonica) and Trumpet Honeysuckle (L. sempervirens), Sweet Autumn Clematis (Clematis terniflora) and Virgin’s Bower (C. virginiana), Japanese Meadowsweet (Spiraea japonica) and Virginia Meadowsweet (S. virginiana), Asian Bittersweet (Celastrus orbiculatus) and American Bittersweet (C. scandens).

Great Blue Heron at Ryoanji Temple in Kyoto

Great Blue Heron at Ryoanji Temple in Kyoto

The disjunct phenomenon is not limited to plants. Similar species have been discovered among fungi, arachnids, millipedes, insects, and freshwater fish. (Yih 2012 [Wen 1999]) Experts continue to research, debate, and refine the interpretation of data collected to more fully illuminate this fascinating connection.

Information for this blog post was derived from the following scientific papers, articles, and Web sites. If my limited scientific study has led to any misrepresentations, I take full responsibility for these errors.

Boufford, D.E., and S.A. Spongberg. 1983. Eastern Asian-eastern North American phytogeographical relationships: A history from the time of Linnaeus to the twentieth century. Annals of the Missouri Botanical Garden 70:423-439.

Graham, Alan. 1993. History of the Vegetation: Cretaceous (Maastrichtian) – Tertiary. Vegetation and Climates of the Past, Flora of North America. floranorthamerica.org

Guo, Qinfeng. 1999. Ecological comparisons between Eastern Asia and North America: historical and geographical perspectives. Journal of Biogeography 26:199-206.

White, Peter S. 1983. Eastern Asian-eastern North American floristic relations: The plant community level. Annals of the Missouri Botanical Garden 70:734-747.

Wofford, B.E. 1989. Floristic elements of the Tennessee Blue Ridge. Journal of the Tennessee Academy of Science 64/3:205-207.

Wood, Carroll E. 1972. Morphology and phytogeography: The classical approach to the study of disjunctions. Annals of the Missouri Botanical Garden 59:107-124.

Xiang, Qiu-Yun, D.E. Soltis, P.S. Soltis. 1998. The eastern Asian and eastern and western North American floristic disjunction: Congruent phylogenetic patterns in seven diverse genera. Molecular Phylogenetics and Evolution 10:177-190.

Yih, David. 2012. Land bridge travelers of the Tertiary: The eastern Asian-eastern North American floristic disjunction. Arnoldia 69/3:14-23.

Radford University, Biomes of the World and Arcto-Tertiary Geoflora
https://php.radford.edu/~swoodwar/biomes/?page_id=94
https://www.radford.edu/~swoodwar/CLASSES/GEOG235/biomes/tbdf/arcto/html

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Alternate-leaved Dogwood

The 62nd Annual Spring Wildflower Pilgrimage is this week. People come from around the world (but mostly the eastern U.S.) to see the glory of the Smokies in April. Unfortunately, Mother Nature’s normal schedule got a bit skewed, and April’s magnificent show burst forth in March this year.

Many of the plants typically in flower can still be found. It just takes some unaccustomed searching to locate those remaining colorful jewels hidden within a swelling sea of green. Most of the Yellow Trillium are already tattered and faded, with some insect-chewed beyond recognition, yet we find a few still displaying intact mottled leaves and lemony petals. Periodically, a Foamflower stalk holds aloft a small cluster of starry flowers. A handful of Creeping Phlox peep from behind a tree, Robin’s Plantain is well past its prime, and we find one lone Fringed Phacelia flower on Porters Creek. Isolated individuals of Star Chickweed, Crested Iris, Sweet Cicely, and Bishop’s Cap require a sharp eye.  A few more spring flowers are in better shape at higher elevation, but down low it is mainly developing fruit and expanding foliage.

Hemlock Polypore

Meadow Parsnip, Canada Violet, Dog Violet, Cream Violet, Vasey’s Trillium, and Daisy Fleabane display fresh blossoms for the Pilgrims. The shrub Hearts-a-bustin’ and the tree Alternate-leaved Dogwood are uncharacteristically in full flower, early by at least a couple of weeks. Two bright spots are Painted Trillium and the Ladies Slippers, both pink and yellow. They are stunning — at least until a hail storm wreaks havoc midweek.

A newly developing Hemlock Polypore

The highlight, though, has to be a fungus. Yes, you read that correctly. It seems as though each Pilgrimage is characterized by a particular organism. One year it was Silverbells, another Dogwoods, last year moths. In 2012, it must be Hemlock Polypore, also known as Hemlock Varnish Shelf. This shiny, showy stalked polypore mushroom is sprouting everywhere.

Hemlock Polypores stand erect on their stalks when growing from a horizontal surface.

Ganoderma tsugae may be found singly or in groups on dead or dying conifer trunks, logs or stumps, particularly Eastern Hemlock. Here in the Smokies there are plenty of dead and dying Hemlocks to feed this common saprobic fungus. The fruit bodies appear spring to fall and persist throughout the year.

Hemlock Polypore viewed from below

The stalk is 1-6 inches long and cylindrical to slightly flattened. Growing laterally on trunks and stumps, the stalk often grows erect when emerging from a horizontal surface such as a downed log. The cap is a globular white knob at first and expands into a fan or kidney shape from 3 to 12 inches across. The base of the stalk is deep mahogany brown. This color progressively lightens to a pale orangey yellow with a bright white rim along the outer edge when the mushroom is young. The stalk and upper surface are very shiny giving a polished or ‘varnished’ appearance. The lower surface is white, aging to yellowish brown, and covered with minute round to angular pores in a shallow layer. Spores are rusty brown. The mushroom goes from soft and spongy in texture when fresh to firm and corky.

The pore surface of a Hemlock Polypore

In Mushrooms of West Virginia and the Central Appalachians, William C. Roody reports that while the Hemlock Polypore is not edible, a healthful tea tonic can be brewed from the fruit. However, there are some critters who find it edible. Several of the individual mushrooms have large orange and black beetles crawling on the surface and chewing the flesh.  Megalodacne heros is in the Erotylidae Family, known collectively as the Pleasing Fungus Beetles.

Pleasing Fungus Beetles on Hemlock Polypore

While searching an explanation for such a unique common name, I learned from the University of Florida Entomology & Nematology Web site that most of these beetles are tropical. Out of 1,800 known species, just 51 have been found on this continent north of Mexico. With their distinctive color pattern, they are easy to spot but due to “cryptic habits” are not often seen except by mushroom hunters and entomologists. They have clubbed antennae, among other distinguishing structural characters, and are oblong oval to egg shaped. There are other beetle species that share similar color patterns.

An open Hygrometer Earthstar

Pleasing fungus beetles feed on, what else, fungi. Each genus of beetle seems to specialize on a particular group of fungi. Megalodacne spp., both larvae and adults, can be found in large numbers on the mature fruiting bodies of harder bracket fungi, including the stalked polypore Ganoderma. The larvae grow quickly while fresh fungi are available. When fungi are not fruiting, the beetles will hide under bark and other places, sometimes in large numbers.

A closed Hygrometer Earthstar

I must thank Maine Pilgrim Frances for pointing out two aging Hygrometer Earthstars (Astraeus hygrometricus) near Baskins Creek along the manway. One specimen shows the starry appearance of this puffball mushroom when the outer wall splits open and folds back. The other shows the rays closed tightly around the spore case. In dry weather, the rays curl up to protect the spore case until rainy conditions prompt them to open and recline exposing the spore case to more amenable conditions.

The little larva responsible for rolled Witch Hazel leaves

While photographing fungi at leisure Sunday morning, I unroll a Witch Hazel leaf in hopes of finding the culprit responsible for the furled foliage. Inside is a tiny translucent caterpillar with a shiny black head and lots of frass. After taking a photo, I roll it up again and let it resume feeding unmolested. It is such a nondescript little thing, heaven only knows what it will become.

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Allen gazing into Whiteoak Sink.

Certain places just get in the blood. There are people for whom hiking Mt. LeConte is an annual rite. Porters Creek is a sentimental favorite of mine. Whiteoak Sink has a hold on Allen Sweetser. He and Susan share interest in a cabin just a short walk outside the park boundary at Schoolhouse Gap, allowing him to roam that bowl at will for the past 30 years. He’s climbed in and out from many different directions in all seasons, exploring every depression and identifying the plants to better understand Whiteoak Sink’s natural history. He’s consulted old photographs among other archived material and tagged alongside a neighbor and lifelong resident recounting the families and industry (sawmill) of its cultural history.

The winter foliage of Sharp-lobed Liverleaf and Two-leaved Toothwort

Walking Whiteoak Sink with Allen is special. He moves through it with an intuitive grace that can only come from intimate knowledge gained slowly and methodically, like an old caretaker acutely sensing every nuance. He loves this place. What a treat for Clarence and me to spend the day wandering Whiteoak Sink with Allen as our guide. The sky is heavy with clouds, and rain is a constant threat. Apart from a brief, stray shower, however, the threat is mostly an empty one. We walk up the gravel road intersecting the top of Schoolhouse Gap Trail and head down to the well-traveled manway just before Turkey Pen Ridge.

Allen and Clarence at the waterfall

Lush growth fills Whiteoak Sink in the summer, so winter is a great opportunity to gauge and survey the land. We walk to the usual attractions — the disappearing waterfall and the Blowhole, then head off to see a number of smaller sinks. Like a limestone nesting doll, Whiteoak Sink contains several other pits and depressions. Two of them are named for the profusion of certain spring wildflowers found in and around them — Bluebell Hole and Shooting Star Hole. Allen says the Virginia Bluebells seem to be on the decline, noting fewer of them in recent years.

Frog eggs in a tiny pool of water

Given the soft, soluble limestone, one tiny spot in Whiteoak Sink presents a geologic mystery. Allen walks us straight to a shallow pool of water about five or six feet across. Several clusters of frog eggs are in it. According to Allen, this little pool nearly always contains water. Where does the water come from? Why doesn’t it perk through the soil and drain away? Whatever the explanation, the sink’s frogs are undoubtedly grateful.

Hazelnut catkins shedding pollen in early February

One lone grave may be found on a small ridge near the manway. Abraham Law (1790-1864) lies peacefully at the crest with a small engraved rock, a few pine cones, and a red plastic rose to mark his final resting place. Further in, an occasional roof shingle or piece of siding is evidence of the 2011 tornado that struck the park just northwest of Cades Cove.

Rich soil in Whiteoak Sink combines with the protecting rim to offer plants an ideal place for living and growing in relative luxury. We see last year’s mottled foliage of Liverleaf (Hepatica acutiloba or Hepatica nobilis var. acuta or Anemone acutiloba — the last botanical name is the most recent taxonomic adjustment) and this year’s fresh foliage of Two-leaved Toothwort. Hazelnut shrubs are expanding male catkins. A striking patch of Puttyroot leaves graces the ground at the base of a tree.

The winter leaves of Cranefly Orchid and Puttyroot growing together at Allen's cabin

Following a nearly invisible path that puts us perhaps a mile out on Scott Gap Trail, we hike the boundary back to Schoolhouse Gap and down to Allen’s cabin. Just in time too. The rain decides to make good on its threat with a well-timed downpour.

The eroded limestone "amphitheater" at Walls of Jericho

I’d like to share one additional geologic wonder in limestone, though this one is not in the park. Walls of Jericho is a State Natural Area in Tennessee found in the dissected western edge of the Cumberland Plateau along the Alabama border. Millions of years of water have eroded plunge pools and tunnels through the rock and created a natural amphitheater of limestone within sheer walls best described as a canyon. Clarence and I hike to Walls of Jericho March 16. We take the Alabama trail in and follow a less traveled, longer route out into Tennessee. Just off that trail is Mill Creek Blow Hole. Expecting something similar to Whiteoak Sink’s Blowhole and anticipating the rush of cool air on this very hot day, we head down a steep path into a narrow ravine to find an explosive rush of churning whitewater shooting out from a side cavern, slamming against the bedrock on the opposite side, then rocketing down a natural sluiceway like some terrifying log flume ride. A visit to Walls of Jericho is highly recommended.

Thar she blows! The Mill Creek Blow Hole at Walls of Jericho

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Three Birds Orchid

These two relaxed days of searching for tiny treasures not only yield some great photos, but provide ample opportunities for expanding knowledge too. And as a special bonus, such quiet pursuits also serve to refresh the spirit. A lifetime puttering through these mountains daily would never lack stimulating interests for the mind or soothing balm for the soul.

Dr. Ken McFarland and his wife Linda drive up Sunday afternoon to walk Injun Creek and examine mosses. Ken leads hikes on this trail during the Spring Wildflower Pilgrimage demonstrating the finer points (pun intended) of several of the common mosses in the park. There are also liverworts and even one hornwort on the trail as well. Under his tutelage, I closely view these tiny plants through a hand lens and take notes with the intent to photograph them in the following days.

Fern Moss often carpets logs.

Mosses, liverworts, and hornworts are collectively referred to as bryophytes. They do not possess water-transporting tissues in the same manner as other plants and are considered “non-vascular.”  Absorbing needed water through leaf tissue, a moist habitat is often critical to the survival and reproduction of many of these species. Sometimes just a single cell layer thick, they can change color and curl in dry conditions, but at the first touch of moisture, they green up, unfurl, and are ready to resume vital processes such as photosynthesis.

Atrichum Moss has translucent wavy edges.

Droughty summers aside, the Smokies provide an ideal habitat for these plants. Mossy logs, rocks, and trailsides abound here thanks to high annual rainfall and plenty of seeps, springs, and streams. There are a few distinguishing characteristics of mosses. Typical moss leaves have a midrib, taper to a single point, and are arranged spirally around the stem. Leafy liverwort leaves lack a midrib, are either rounded or lobed with two or more points, and align in two distinct rows along the stem. Liverworts can also produce thin, flat tissue called a thallus rather than a leafy stem. Hornworts are similar in appearance to a thallus liverwort, but with the aid of a hand lens a single chloroplast is visible in each cell.

Transparent leaf tips of Bryoandersonia are twisted in a spiral.

Two genera of mosses, Hypnum and Thuidium, are often called “log mosses” as they can be found carpeting old downed trees. Thuidium, the fern moss, is decompound –the leaves branch multiple times to give it a delicate, feathery look. Thuidium delicatulum is by far the most common of the three species found in the Southern Appalachians.

Robust clumps of Atrichum moss are commonly found in moist shady areas. The spirally arranged leaves splay out from erect stems in a starry fashion. The darker midrib is easily detectable with wavy-edged translucent leaf tissue to either side.

Mnium leaves have tiny teeth and a pointed tip.

Mnium has broad, nearly transparent leaves with tiny teeth and a midrib that projects into a point at the leaf tip. Some shoots lie flat, others stand erect in little rosettes. Rhodobryum roseum is a distinctive moss that also grows in rosettes.

A species found on rock, soil, and tree bases throughout Eastern North America is Bryoandersonia illecebra. Ken describes the drooping, round leafy shoots as cat tails, which give populations a shaggy look. The long, tapering leaf tips are transparent with a spiral twist. It is quite common, almost weedy.

Leafy liverworts like Norwellia are the first to colonize a log.

Leafy liverworts can be found on tree bark and downed logs as well as streams and seeps. The green growth that first colonizes a decorticated (without bark) log is usually a leafy liverwort, Norwellia. From a distance it looks to be a smooth, solid coating like algae, but close inspection reveals fine strands with tiny curved, double pointed leaves. Mosses arrive later in the next successional wave of life on the log.

Norwellia liverwort is tiny.

A closeup of the fine-haired leaves of Trichocolea tomentella.

Another really cool leafy liverwort is Trichocolea tomentella. It is pale green and many-branched with something of a puffed, fuzzy look thanks to leaves that are made up of numerous tiny, hair-like filaments. It is found close to streams.

Conocephalum salebrosum, a thallus liverwort

There are two easily recognizable, large thallus liverworts in the park. In streams and other wet areas look for Conocephalum salebrosum with its scaly looking polygonal pattern. There will often be large patches of it. Dumortiera hirsuta has a dark green, smooth thallus and in spring produces slightly elevated, hairy discs to protect the sporophytes.

White Micrathena Spider

While photographing the liverworts, I notice a small white spider on a nearby leaf. She is camera shy at first, trotting from one side of the leaf to the other as I attempt to take her picture. She finally relents. It is a White Micrathena (Micrathena mitrata) related to the gray, big-butt Spiny Micrathena Mary and I kept running into on Old Settlers. It has two small projections on its back. Along the Plemmons Cemetery trail, I find a few of the gray, big-butt spiders and several of these smaller White Micrathena with their webs stretched between the shrubs.

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