Herbivory

I could find no information on herbivory of this plant, likely because it is too uncommon for any herbivores to actively select. Cephalanthera austiniae lacks any external structures such as trichomes as defenses.

Snails have been seen consuming another species from Cephalanthera, suggesting that this plant is occasionally eaten by herbivores. My guess is that when the Phantom Orchid rarely does flower, it takes a chance when it does so. Since the root system is much larger and more extensive than the flowering stem itself, it can produce more flowers even after it has been eaten or damaged.

The flowers of Cephalanthera austiniae are totally white, with a small spot of yellow on the tips of the flowers. This yellow coloration is one good indicator that this orchid is pollinated by insects, providing a guide for them to land. It has fairly large flowers for an orchid (about 3 cm long) and produces over twenty-five of them. The flowers are subsessile with three lobes, and have a cupped appearance, as the flower never opens fully. 

The flower is said to smell faintly of vanilla, and has a sticky stigma. This stickiness acts as a kind of glue, so that when insects enter the flower to collect nectar, the pollen becomes stuck to them. The insects it attracts are typically small flies, though it doesn't seem terribly picky about who pollinates it, as its mechanism for pollination is a fairly simple one.

Leaves

To be honest, I'm a bit at a loss as to how to discuss the leaves of Cephalanthera austiniae, seeing as that it… doesn't actually have them. 

Photo by: Nature Blog Network

Not a single leaf to be seen here.

While some interesting leaf-like bracts can often be seen along the lower stem, these are simply structures that emerge from where the stem is sheathing. 

So instead, I will be discussing how it manages to function without them. With a complete lack of chlorophyll, there's no photosynthesis going on in this plant. And as you can imagine for a leafless plant, it typically grows in the shade, with no need to catch sunlight. So how exactly does it obtain energy?

The Phantom Orchid is one of the few plants which fall under the special category of achlorophyllous mycotrophic angiosperms, a category shared by Indian pipe and Pine drops. This lengthy term translates to "flowing plants without chlorophyll that utilize fungi in their nutrition". In fact, the flowering stem that you see in the above image is only a small component of the full organism. Most of the plant lurks underground, where it leeches nutrients and energy from black thelephoroid fungi.

Photo by: UC Berkeley

This fungus is only found in the presence of certain species of old-growth or mature trees, as it relies on a symbiotic relationship with them. These particular tree species are currently unknown. From this information, we can conclude that the full relationship of the Phantom Orchid can be described as an unusual orchid-fungi-tree partnership. Considering this requirement for survival and the decline of old-growth forests, it's little wonder why Cephalanthera austiniae is an endangered species. 

While I wasn't able to find much information on the seeds of the Phantom Orchid specifically, there is some interesting data on Cephalanthera in general. Orchid seeds are some of the smallest amongst angiosperms. The common explanation behind this is that the dust-like seeds are easily wind-borne, and thus have the ability to disperse great distances. 

Image by W.P. Armstrong

In this image, you can see exactly how tiny orchid seeds tend to be. This is one capsule of an unknown orchid, carrying approximately one million seeds.

In terms of structure, Phantom Orchid seeds oddly enough do not contain a food reserve. Instead, only the embryo can be found within its shell. This would seem to account for how its seeds manage to be so small. After dispersal, the seeds need to find mycorrhizal fungi rather soon, or they will die without a food source. 

Cephalanthera austiniae is pollinated by insects, and apparently isn't very picky about which insects happen to pollinate it. The flowers give off a faint, vanilla-like scent. They have a sticky stigma, so that when insects enter the flower, the pollen becomes stuck to their bodies. The pollen is then dispersed in the next orchid that is visited. However, there has been a noticeable decline of pollinators as of recent history, most likely because of habitat destruction. Because of this, some efforts to hand-pollinate them have been made, which have resulted in successful, seed-bearing capsules.

#1. Why did you pick this species? Tell us something interesting about it. 

I picked  Cephalanthera austiniae because it is a rare and unusual plant from Washington, which is my home state. While I've never actually seen it, it's something I've kept an eye out for. This orchid is very striking as it lacks chlorophyll, leaving the plant a nearly pure white color. It also has no leaves. What made me really interested in it was that I was curious as to how a plant like this functions.

Image: Native Orchids of the Pacific Northwest

As it turns out, the reason for all of these traits is that it derives all its nutrients from mycorrhizal fungi, which convert sugars that the orchid can use. The mycorrhizal fungi are unwilling participants in this process, as Cephalanthera austiniae is parasitic. Another odd fact is that it's the only plant of its genus found outside Europe and Asia.



#2. Please provide taxonomic information: Phylum, class order, family. Are there any controversies with respect to its classification? What is / are its common name(s) (if any)? Who is the authority (the person who named the plant)?

It is in the Anthophyta phylum, the Monocotyledoneae class, the Lilopsida order, and the Orchidaceae family. It's most commonly called Phantom Orchid, though it is also called by some Snow Orchid, both referring to its white color. This plant was named by A. Heller. (http://a100.gov.bc.ca/pub/eswp/)