Photo by Atlas of Wonders licensed under CC BY-NC-ND 2.0

Curious images of these strange green mounds make the rounds of social media every so often. What kind of alien life form is this? Is it a moss? Is it a fungus? The answer may surprise you!

These large, green mounds are comprised of a colony of plants in the carrot family! The Yareta, or Azorella compacta, hails from the Andes and only grows between 3,200 and 4,500 meters (10,500 - 14,750 ft) in elevation. Its tightly compacted growth habit is an adaptation to its high elevation lifestyle. Cushion growth like this helps these plants prevent heat and water loss in these cold, dry, windy environments.

Every so often, these mats erupt with tiny flowers, which must be a sight to behold! Photo by Lon&Queta licensed under CC BY-NC-SA 2.0

As you might imagine, these plants are extremely slow growers. By studying their growth rates over time, experts estimate that individual colonies expand at the rate of roughly 1.5 cm each year. By extrapolating these rates to the measurements of large colonies, we get a remarkable picture of how old some of these plants truly are. Indeed, some of the largest colonies are estimated at over 3000 years old, making them some of the oldest living organisms on the planet!

Sadly, the dense growth of the plant makes it highly sought after as a fuel source. Massive chunks of these plants are harvested with pick axes and burned as a source of heat. Due to their slow growth rate, overharvesting in recent years has caused a serious decline in Yareta populations. Local governments have since enacted laws to protect this species in hopes that it will give colonies the time they need to recover. Indeed, some recovery has already been documented, however, continued monitoring and management will be needed to ensure their populations remain viable into the foreseeable future.

Photo Credits: [1] [2]

Further Reading: [1] [2] [3]

I officially learned how to botanize in the American west. Before then my skills were limited to "hey, look at the pretty flower" and then Googling my way to an answer. As such, I have a real soft spot for western botany. Despite the fact that I have not had the chance to exercise those muscles in some time, I nonetheless revisit the few groups that I do remember via the massive photo collection I built up during my tenure in Wyoming. One group I am particularly fond of are members of the genus Lomatium.

I had never really paid attention to members of the carrot family. I always associated that group with the Queen Anne's lace (Daucus carota) I encountered growing in ditches. In other words, I found them boring. All of that changed when I moved to Wyoming. Spring was slow to start that year. I mean really slow. I thought I had it bad in western New York where spring snow storms and freezing temperatures often delayed plant growth well into May. That year in Wyoming, the last snow storm hit on June 29th. Because of this, most of the plants we were trying to locate were biding their time underground waiting for favorable weather to kick off the growing season.

By mid June I was starving for plant life. I needed to see some greenery. That is when I first laid eyes on a Lomatium. They began appearing as tight clusters of highly dissected, rubbery leaves. Once I knew what to look for, I began finding them throughout the foothill regions where we were working. Since I was just getting familiar with the local flora, I was hard pressed to key anything out. Instead I just waited for flowers. I didn't have to wait very long.

Soon entire hillsides were covered in little yellow umbels. They were squat plants, never growing too high. The constant winds that whipped across the terrain made sure of that. It soon became apparent that Lomatiums don't waste any time. Water is limited in these habitats and they have to make quick work of it while it is available. Another interesting thing to note is the sex of the flowers. Generally when I see a dense umbel like that, I just assumed they were hermaphroditic. In at least some Lomatium, this is actually not the case. The sex of the flowers is determined by age.

Smaller plants tend to produce male flowers, whereas larger plants will produce hermaphrodites. This makes a lot of sense as producing only pollen requires much fewer resources than producing ovaries and eventually seeds. Needless to say, larger plants also produce the most seed and are often the driving force in population persistence and growth. The seeds themselves are quite interesting. They are winged and often quite fleshy until they dry. Wind is the predominant seed dispersal mechanism and there is no shortage of wind in sagebrush country.

The phylogeny of this genus is quite confusing. I certainly haven't gotten my head wrapped around it. Individuals are notoriously hard to identify both physically and genetically. There is a large degree of genetic variation between plants and "new species" are still being discovered. At the same time, there is also a lot of endemism and some species like Lomatium cookii and Lomatium dissectum are of conservation concern. Aside from habitat destruction, over-grazing, and limited ranges, over-collection for herbal uses poses considerable threat to many species.

Further Reading:

http://bit.ly/1VWvMfV

http://bit.ly/1VE24MF

http://bit.ly/1WUzohQ

http://bit.ly/1qXSVS8

http://bit.ly/245NDpH