I live for moments like this. The only downside to that is I can never really predict when they are going to happen. There I was driving up a mountain road in search of a handful of other plant species related to my research. The road was narrow and there was a steep bank on the drivers side. The Southern Appalachian Mountains are brimming with botanical diversity. As such, it can be hard to tease out individual plants, especially while driving. This is why having a refined search image comes in handy.

I was rounding a bend in the road when something out my window caught my eye. My mind went racing and it wasn't long before a suspicion crept into my head. If I was right, this was an opportunity I was not going to miss. I found the nearest pull off, parked the truck, and ran back down the road. I am so happy that I decided to trust my instincts. There in front of me was a small population of whorled pogonia orchids (Isotria verticillata).

It was like being in the presence of a celebrity that I had been stalking for years. This was an orchid I have been dying to see. The harder I looked the more I saw. I had to sit down. Here in front of me was a species of orchid that isn't seen by many. In fact, entire populations of these species can go unseen for decades until they have enough energy to flower.

Flowering in this species is said to be quite erratic. Because they live in shaded environments, building up the energy needed to reproduce can be difficult. Like all orchids, the whorled pogonia relies on an obligate relationship with mycorrhizal fungi to supply the nutrients it needs. In return, the orchids provide fungi with carbohydrates. The problem with erratic flowering, however, is that it makes reproduction difficult. Rarely are two populations flowering at the same time and in close enough proximity for successful cross pollination. More often, these orchids will self fertilize, which can lead to high rates of inbreeding.

Large bees are the main pollinators of the whorled pogonia. The flowers themselves are reported to produce a feint odor reminiscent of Vanilla. This is interesting to note because in the greater scheme of orchid phylogenetics, this species is placed in the Vanilla subfamily, although such distinctions can get muddled quickly. Regardless, simply being in the presence of this orchid was enough to give me goosebumps. It is a shame that such a species is being lost throughout much of its range.

Further Reading:
http://bit.ly/1ssBmdF

http://bit.ly/1WEmZzm

Photo by Scott Zona licensed under CC BY-NC 2.0

I am beginning to think that there is no strategy for survival that is off-limits to the orchid family. Yes, as you may have figured out by now, I am a bit obsessed with these plants. Can you really blame me though? Take for instance Schomburgkia tibicinis (though you may also see it listed under the genera Laelia or more accurately, Myrmecophila). These North, Central, and South American orchids are more commonly referred to as cow-horn orchids because they possess hollow pseudobulbs that have been said to been used by children as toy horns. What is the point of these hollow pseudobulbs?

A paper published back in 1989 in the American Journal of Botany found the answer to that question. As it turns out, ants are quite closely associated with orchids in this genus. They crawl all over the flowers, feeding on nectar. The relationship goes much deeper though. If you were to cut open one of these hollow pseudobulbs, you would find ant colonies living within them. The ants nest inside and often pile up great stores of food and eventually waste within these chambers. The walls of the chambers are lined with a dark tissue that was suspect to researchers.

Using radioactively labeled ants, the researchers found that the orchids were actually taking up nutrients from the ant middens! What's more, nutrients weren't found solely in adjacent tissues but also far away, in the actively growing parts of the roots. These orchids are not only absorbing nutrients from the ants but also translocating it to growing tissues.

While orchids without a resident ant colony seem to do okay, it is believed that orchids with a resident ant colony do ever so slightly better. This makes sense. These orchids grow as epiphytes on trees, a niche that is not high in nutrients. Any additional sources of nutrients these plants can get will undoubtedly aid in their long-term survival. Also, because the ants use the orchids as a food source and a nest site, they are likely defending them from herbivores.

Photo Credit: Scott.Zona (http://bit.ly/1hvWiGX)

Further Reading:
http://www.jstor.org/stable/2444355