Jewels of the Alpine Tundra

     During the winter months in Colorado, some of the higher reaches of the Rocky Mountains can reach temperatures as low as -40 degrees Fahrenheit(1), which puts the alpine tundra environment in a climate zone similar to much of Northern Canada or Scandinavia(2). On top of this, the soil of the tundra is riddled with rocks and gravel. Plants that grow in this zone have to be incredibly tough to survive and often have adaptations to survive in cold and wind such as short stature and coverings of hairs.
     These smaller plants also produce small, showy blossoms that cover the alpine tundra like precious gems, and which are a fantastic pleasure for sore hikers to behold. The way that tiny, exquisite alpine flowers seem to emerge from hiding might remind a reflective observer of the aesthetic principles used in Japanese gardening: as small features in the landscape give way to reveal them, each part of the garden should be a microcosm of the principles of natural beauty, only to be revealed from the proper perspective and within the proper context. A hiker who wants to appreciate these plants will need to slow down and stoop low, which fortunately is the involuntary modus operandi of an oxygen-starved, high-altitude hiker anyhow.
     I thought that the dead of winter would be a fun time to post about these impressive survivors, as they somehow manage to avoid tissue death in the arctic weather that we see in the high mountains from September through June. There are a large number of attractive and unusual species that populate the high alpine areas of the state. This post will take a quick and very non-exhaustive survey of the flowers that bejewel the high places of Colorado.
     For fear of writing redundantly, I will simply note here that all of the flowers featured in this post may bloom between July and August depending upon their elevation. Also, a handy chart of leaf shapes may be found here in order to clarify some of the terms used.

Eritrichium nanum, Alpine Forget-Me-Not     

E. nanum growing on the slopes of Pikes Peak. The brilliant yellow and and blue flowers 

are unlike anything else other than members of the same family. These plants 

were growing at around 12,000 ft elevation on a wet, north-facing alpine meadow.

The alpine forget-me-not in perspective. The tiny, fuzzy blue blob at the center 

of the photo (click to enlarge) is E. nanum, while the relatively large glossy leaves of 

Dryas octopetela at top right center are actually no longer than an inch. 

     The alpine forget-me-not is a great example of plants in the borage family, Boraginaceae. The five-petaled blue flowers, pubescence on stems and flower buds, and lanceolate leaves are all good field marks not just of this particular flower but of borage family flowers generally. A good rule of thumb in flower identification is that five-petaled flowers which are densely hairy are best investigated as Boriganaceae members before trying other families. This is seen in some other Colorado species such as the genera Cryptantha and Phacelia, although some related genera such as Mertensia give the hairs a skip. 

     The leaves are elliptic to obtuse and densely pubescent (covered in fine hairs), growing little more than a quarter inch long(3). This plant grows tightly appressed to the tundra soil, which coupled with its densely hairy foliage serve as adaptations against the punishing cold and wind of the alpine tundra. This flower is unmistakable for anything else that grows in its same climatic zone except for Myosotis alpestris, which is highly similar in appearance but larger and does not form small, silver mounds of foliage(4). 

Saxifraga chrysantha, Golden Saxifrage

S. chrysantha growing near 14,000ft on Mount Evans. Despite the showy flowers I 

almost missed these between the scree and granite boulders. 

     This flower presents a nice example of the sorts of saxifrages that we tend to see in Colorado, which frequently have low-growing, succulent leaves growing in rosettes and showy, colorful flowers with four or five petals. The perfectly formed rosettes of triangular to ovate leaves are so small that they might be mistaken by a fast-moving hiker for a moss. The fleshy yellow flowers, by comparison, are easy to see and to recognize. Each flower sports five petals and a yellow or  red conical to spherical center. The pedicels and the sepals will reveal a subtle pubescence when viewed with a hand lens(5). Blossoms and all, this plant will not grow higher than an inch or two. The  specific epithet chrysantha simply means "golden flower" in Greek. 

Androsace chamaejasme, Sweetflower Rockjasmine

A. chamaejasme growing around 11,500 ft on Pike's Peak. The flowers in this photo show 

the characteristic bright yellow center, which ages to an eye-popping pink. 

     Something about high altitude seems to love a tiny, pubescent flower with five petals and rosetted leaves. The trend continues with sweetflower rockjasmine, which has no relation to the fragrant tropical jasmines(6) nor, presumably, to the Disney princess. Despite this, its specific epithet means "low/ground jasmine." To add to the confusion, despite its superficial resemblance to flowers in Boraginaceae, this little flower actually hails from the primrose family: Primulaceae. Other members of this family such as those that I looked at in this post seem to bear little resemblance to this flower, so the phylogenic similarities must be fairly subtle.

     A. chamaejasme consists of succulent obtuse to elliptical leaves covered in a fine pubescence which grow in rosettes about 1/2 inch across. These give rise to pedicels not taller than two inches supporting an umbel of five-petaled flowers with bright yellow centers. Interestingly, as the blossoms age the centers of the flowers can turn a shocking bubblegum pink, even as other flowers on the same umbel retain their yellow coloration. I cannot find any information on why this is, but I assume it is due to the intense ultraviolet radiation present at high altitude wearing down the pigments in the petals. 

Dryas octopetala, Mountain Dryad

The flowers of D. octopetela form white mats in the high alpine tundra. The leaves are distinctively

shaped and tend to stand erect.

D. octopetela turning the flanks of Pike's Peak white. It often colonizes extensive areas. This 

Meadow was at around 12,000 ft elevation.

     Another beautiful, itty-bitty flower of the tundra is the aptly named Dryas octopetela, whose specific epithet simply refers to its eight petals. The lanceolate leaves are slightly glossy, have distinct crenate margins, and stand erect in (wait for it) rosettes, which in turn form great mats across the tundra. The white flowers are one to a stalk, and are superficially similar to globeflowers or marsh merigolds, but can be distinguished by their eight petals, the foliage of the plants, and the height of the flowers. D. octopetela hugs the ground while the other two species tend to grow taller. This is a circumpolar species which is well-distributed through alpine and arctic areas of the Northern Hemisphere(7). The relative ages of genetic lineages of D. octopetela in different regions are used in research on dating the advance and retreat of ice age glaciations.

Claytonia megarhiza, Alpine Springbeauty  

C. megarhiza in flower around 14,000 ft on Mt. Evans. "Springbeauty" is 

something of a misnomer, as this plant's spring (in terms of blooming) comes in 

late July to August.

The leaves of C. megarhiza turn a gorgeous shade of crimson when cold weather 

starts to set in. The autumn foliage is more noticeable and showy than the flowers.

This individual is stretching out and taking up space. I have noticed that when C. megarhiza 

grows at lower altitudes the leaves tend to be more variable and the plant larger. 

          This is probably my favorite wildflower in all the Rocky Mountains, although the flowers themselves are actually not terribly impressive. The sprawling, fleshy, glabrous, and obtuse to elliptic leaves can seem almost bawdy compared to the other tightly compact plants that inhabit the same life zone. C. megarhiza is also bigger than many plants which live in similar circumstances, with its rosettes reaching up to several inches in diameter. The five-petaled flowers may be pink or white and have a strong yellow coloration proximally. "Megarhiza" means "large root" and is an apt specific epithet as each plant is perched atop a colossal underground taproot. This root may reach up to a meter in length as it worms its way between cracks in the bedrock in search of water and anything resembling soil. An observant appreciator of plants in the purslane family, of which C. megarhiza is a member, will note a strong resemblance to the flowers of its lower altitude cousin Claytonia lanceolata. As noted in the photo above, C. megarhiza takes on a brilliant red hue as autumn sets in. A high slope may almost look like it's covered in rose blossoms as thousands of alpine springbeauties prepare themselves for dormancy. 

     Thank you for checking out this post on tiny alpine flowers. I find these flowers particularly pleasing and interesting to view and learn about due to their exaggerated geometry and the evanescence of their flowering season. I hope that this entry will help to spread my joy regarding these exceptional plants!

References 

1. United States Department of Agriculture [USDA]. (2012). USDA Climate Zone Hardiness Map. Retrieved from: http://planthardiness.ars.usda.gov/PHZMWeb/#
2. Peel et al (2007). Updated Köppen-Geiger climate map of the world. Retrieved from: http://people.eng.unimelb.edu.au/mpeel/koppen.html
3. Mammoser, D., & Tekiela, S. (2007). Wildflowers of Colorado. Cambridge, Minnesota: Adventure Publications, Inc.
4. Craighead, J. J., Craighead., F. C., & Davis, R. J. (1963). A Field Guide to Rocky Mountain Wildflowers. Boston, MA: Houghton Mifflin Company.
5. Schnieder, A. (n.d.) Saxifraga chrysantha. Retrieved from: http://www.swcoloradowildflowers.com/Yellow%20Enlarged%20Photo%20Pages/saxifraga%20chrysantha.htm
6. Androsace chamaejasme (n.d.). Retrieved 4 January, 2016 from https://en.wikipedia.org/wiki/Jasmine
7. United States Department of Agriculture [USDA](n.d.). Mountain avens. Retrieved from: http://www.fs.fed.us/wildflowers/plant-of-the-week/dryas_octopetala.shtml