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/)