Saturday, October 31, 2009

The Ghost Plant, a Halloween Appropriate Post

During the Iron Age in Europe, tribes residing in what is the modern day British Isles celebrated the end of summer with a pagan-rooted festival called “Samhain,” which literally translates to “summer’s end” in the Goidelic language used between the 6th and 10th centuries. In conjunction with this festival the Celts believed that the realm of the dead overlapped with the world of the living, and that through divination long dead ancestors could help foretell events of the upcoming year. Samhain is one of many festivals that contributed to the ontogeny of what is now refereed to as Halloween, and like most of the other harvest celebrations it embraced the idea of spirits and ghosts intermingling with the material world. It is in homage to such celebrations of the spirit realm that this post is written; it briefly describes a fascinating plant that has evolved to take on a ghostly appearance and to occupy a unique niche in which it parasitizes parasites, introducing the “ghost plant”.

Due to its eerie appearance and non-typical angiosperm ecology, Monotropa uniflora has been dubbed both the “ghost plant” and the “corpse plan,” though it is also called – less spookily – the “Indian pipe” (undoubtedly because of its ‘uniflora’ which when combined with an elongate stem resembles a smoking pipe). A member of the Ericaceae Family, M. Uniflora is one of about 400 angiosperm species that exhibit an achlorophyllous physiology; they lack chlorophyll and consequently don’t undertake photosynthesis as an energetic process. The lack of chlorophyll is why the plant isn’t green in appearance; rather it displays a white-to-pink hue and exhibits translucence, thus causing it to look like a mushroom or fungus.

Although not a fungus, the ghost plant does take on some fungal-like habits, but before getting to those here are a couple of snapshots of Monotropa uniflora taken earlier this week to serve as a visual aid:

Because Monotropa uniflora doesn’t photosynthesize it doesn’t require sunlight to grow and can even grow in the dark. This ability grants the plant the opportunity to do very well on forests floors which underlay dense canopies that limit the quantity of light penetrating to the herbaceous stratum. The lack of photosynthetic ability means that ghost plant implores a different strategy to acquire and process energy, like many of the fungi that it superficially resembles the plant has adapted to be parasitic.

Not only is the corpse plant a parasite, but even further it is a parasite of parasites! Monotropa uniflora is a myco-heterotroph, this means that it has developed a symbiotic relationship with a fungus. More specifically, M. uniflora parasitizes the ectomycorrhizas (ECM) found on the roots of woody trees.

So, the roots of woody trees (pine, oak, etc…) are parasitized by ECMs, such as members of the Basidiomycota and Ascomycota families and, in turn, these fungi are parasitized by an angiosperm - the ghost plant! These symbiotic relationships can be highly specialized, and in the case of the species Monotropa uniflora Young (et. al.) found that the ghost plant parasitizes members the fungi family Russulaceae specifically.

As another visual aid, here is a photo from the above mentioned research article published in the journal Mycorrhiza showing a Monotropa cluster of hundreds of mycorrhizal root tips from which several achlorophyllous stems (*) are emerging (Reference below).

Because of its spooky appearance, its inclining to parasitism and its poorly illuminated habitat the ghost plant serves as a fascinating example of adaptation and as a fitting topic for a Samhain day blog post.

Young (2002). Monotropa uniflora: morphological and molecular assessment of mycorrhizae retrieved from sites in the Sub-Boreal Spruce biogeoclimatic zone in central British Columbia Mycorrhiza, 12 (2), 75-82


  1. Nice writeup -- I'm always in awe of number and variety of niches that some creature has found to occupy.

  2. Agreed, the amount of evolutionary/ecological entrepreneurship is astounding; at first glance it seems as though just about every imaginable niche is being utilized - and then you realize that there are uncountable niches you couldn’t even has imagined.