The perplexing case of the spiral leaves

Spiral leaves

I was walking along a sidewalk path during one of my afternoon strolls, when I suddenly spotted a specimen that seemed to be a bit unusual. 

It was growing next to a construction area, and when I came closer to take a look at it, I realized it was because the plant had quite attractive spiral leaves.

Was this a genotypic attribute of the species or variety, or a result of some abiotic or biotic condition that was fleeting and would disappear when the condition was removed?

When I got home I immediately started googling for any other cases of this phenomenon. 

I did find a sedge that had really twisty leaves called Juncus effusus 'Spiralis', but the specimen I found looked different. There was also talk about how such a form seems to be prevalent in arid and windy regions, perhaps in order to resist the damaging effects of wind. Others hypothesized that such a form would be optimized for photosynthesis, since no matter the location of the sun, some part of the leaf would be placed to intercept its rays. The grass Danthonia spicata has twisted wiry leaves when dried, but these leaves were fresh looking and new, and not wiry at all, so I did not think it was this species.

Twisting or spiral appearance of the flag leaf can be caused by low temperatures (Lindsey et al, 2020)

I also found a paper that noted that the flag leaf of winter wheat (usually Triticum aestivum) can form a spiral when damaged by freezing temperatures (Lindsey et al, 2020, see image above). This effect was accompanied by yellowing or browning of the leaf, something which I did not see in the specimen.

Intrigued by this mystery, I took the specimen home with me, noting that the soil on which it lodged was extremely dry and hard. After placing it in a pot with potting soil, I watered it thoroughly and have been keeping watch on whether any new leaves would bear the same twisting phenotype, and whether the spirals on the older leaves would disappear. It would also give me the chance to identify the plant once it flowers or grows enough blades to be minutely examined.

More on this mystery later, I am sure.

Literature Cited

Lindsey, Laura & Alt, Douglas & Lindsey, Alexander. (2020). Freeze symptoms and associated yield loss in soft red winter wheat. Crop, Forage & Turfgrass Management. 7. 10.1002/cft2.20078. 

The Mysterious Mound in Split Rock (Pennsylvania)

The mysterious grassy mound at Split Rock. The rock formation is behind it, hidden by trees.

Hidden behind a veil of tall trees in deep Pennsylvania lies Split Rock, a gargantuan rock with a cleft in its middle.

We stayed at the nearby Split Rock Resort and Lake Harmony last month and took one day to visit this strange rock formation, which was created 300 million ago when glaciers swept across the land and also created Lake Harmony.

Drone view of Split Rock with the cleft near middle

The rock itself was fascinating, and you can access the top by climbing up a wooden platform. But another thing that caught my eye as we walked from the parking lot was an equally strange small hill or mound that lay to the side of the formation. It was almost dead center in a clearing, surrounded by trees.

It was also covered in grass, but not turf grass. Instead, I noticed Panicum virgatum (switchgrass) and another species that I at first thought was Schizachyrium scoparium (Little Bluestem).

P. virgatum spikelets

The P. virgatum had beautiful purplish spikelets, with purple fuzzy stigmas and orange anthers.

P. virgatum spikelet showing purple stigmas and orange anthers

The other notable species I found was something that I at first thought was S. scoparium. It had fluffy flowerheads and a similar habit to that species.

A.virginicus seedheads

But when I used macro on the spikelets, the first thing that was noticeable was the very long and straight awns. S. scoparium has awns, but they are noticeably bent, and I decided that what I was seeing was Andropogon virginicus, which is a robust species that is even common in disturbed areas.

For more on the spiketlets of the beautiful S. scoparium, click here.

A. virginicus spikelet. (A) Sessile fertile floret with long awn. (B) Sterile floret on a stalk. (C)  Disconnected raceme connection to the other spikelets.

I have no idea how this mound was formed, or even whether it is a natural formation or one that was man-made. When I was there and it was getting into dusk, the entire place felt dark and otherworldly, and I could not help but wonder whether some eerie rituals were held atop this grassy knoll. The somber lighting, dark forested location, and weird clearing would be perfect for some Hollywood horror film. 

If you ever visit this area in Pennsylvania, then take some time to get a glimpse of this mysterious mound with its trove of native grasses, and the riven rock behind it. Just don't do it in the dark!

The Mysterious Origin of Andrews Bald in Great Smoky Mountain National Park

View at Andrews Bald using Panorama setting of Phone Camera

Lying just an hour and a half walk away from one of the most popular tourist destinations in Great Smoky Mountains National Park is a large grassy area that sits atop a mountain. Since it is still below the timberline, all around this open expanse are tall spruce and fir trees, which provide a very shaded environment for hikers who venture out from Clingman's Dome and want to do the 2.5 km trek to this somewhat anomalous area.

The hike itself is moderately easy and quite peaceful, although the almost continuous upward incline on the way back was somewhat strenuous. Recent upgrades to the trail provided nice steps and above-ground planks at certain points that allowed us to move quickly over the sometimes muddy ground.

Narrow boardwalks and steps provide sure footing for hikers

After about an hour and a half we finally burst into the open air and gazed upon an amazing grassy meadow that covered about 1.6 hectares of the mountain top. The change from the dark forested interior to the sunlit top was fairly dramatic, and many people had draped themselves over the lawn-like ground close to the opening, although it was only April and most of the grasses had yet to green and were a dry golden color.

We had finally arrived at Andrews Bald, which at 1800 meters (1.8 km), is the highest so-called "bald" in the Great Smoky Mountains National Park.

Wooden path emerges from forest into Andrews Bald

These "balds" are grassy meadows below the timberline which are found in the southern Appalachian Mountains, and the origins of most are shrouded in mystery. The dominant grass is usually Danthonia compressa, but other grasses such as redtop (Agrostis alba), timothy (Phleum pratense), Canada bluegrass (Poa compressa), Kentucky bluegrass (P. pratense), and red fescue (Festuca rubra) may also be found.

The trail continues, with a view to other parts of the Great Smoky Mountains

Some researchers believe Native Americans originally cleared the areas as hunting grounds or lookouts, and there are historical records that seem to indicate that settlers cleared some of the balds for grazing. There are even some who postulate that the balds had been originally founded by prehistoric herbivores, and then maintained by human hands thereafter.

Whatever the case, there is no doubt that the balds had been used as grazing land during the 1800s. The cattle and sheep that were herded up onto these ridgeline areas during the summer months kept the land open, but after the formation of the national park and the cessation of grazing in the 1930s, trees and shrubs have been slowly reclaiming the land.

Andrews Bald, with visitors (dots on far left) sunning themselves on the golden Springtime grass

A quick look at historical satellite imagery from Google Earth shows that Andrews Bald went from being around 2.5 ha in size in 1995 to around 1.6 ha in 2017 (see image below), and if grazing continues to be excluded from the area, then it is probably inevitable that the bald will continue to shrink in the future. 

But for now, visitors can continue to enjoy the relatively open vista possible in Andrews Bald. It may not be the vast green expanse that it used to be, but I still highly recommend it if you ever visit Great Smoky Mountains National Park.

Area of the meadow shrunk from 2.5 to 1.6 ha from 1995 to 2017