Something Strange in Mexico

lac2.JPG

I assure you that what you are looking at here is indeed a plant. I would like you to meet the peculiar Lacandonia schismatica, one of roughly 55 species belonging to the family Triuridaceae. Not a single member of this family bothers with leaves or even chlorphyll. Instead, all members are mycoheterotrophic, meaning they make their living by parasitizing fungi in the soil. However, that is not why L. schismatica is so strange. Before we get to that, however, it is worth getting to know this plant a little bit better.

The sole member of its genus, Lacandonia schismatica grows in only a few locations in the Lancandon Jungle of southeastern Mexico. Its populations are quite localized and are under threat by encroaching agricultural development. Genetic analyses of the handful of known populations revealed that there is almost no genetic diversity to speak of among the individuals of this species. All in all, these factors have landed this tiny parasite on the endangered species list.

Mature flower of  Lacandonia schismatica . Three yellowish anthers (center) surrounded by rings of red carpels. Scale bar = 0.5cm.”  [SOURCE]

Mature flower of Lacandonia schismatica. Three yellowish anthers (center) surrounded by rings of red carpels. Scale bar = 0.5cm.” [SOURCE]

To figure out why L. schismatica is so peculiar, you have to take a closer look at its flowers. If you knew what to look for, you would soon realize that L. schismatica appear to be doing things in reverse. To the best of our knowledge, L. schismatica is the only plant in the world that known to have an inverted flower arrangement. The anthers of this species are clustered in the center of the flower surrounded by a ring of 60 or so pistils. The flowers are cleistogamous, which means they are fertilized before they even open, hence the lack of genetic diversity among individuals. 

Not all of its flowers take on this appearance. Researchers have found that in any given population, a handful of unisexual flowers will sometimes be produced. Even the bisexual flowers themselves seem to exhibit at least some variation in the amount of sexual organs present. Still, when bisexual flowers are produced, they only ever exhibit this odd inverted arrangement.

lac1.JPG

It is not quite clear how this system could have evolved in this species. Indeed, this unique floral morphology has made this species very hard to classify. Genetic analysis suggests a relation to the mycoheterotrphic family Triuridaceae. It was discovered that every once in a while, a closely related species known as Triuris brevistylis will sometimes produce flowers with a similar inverted morphology.

This suggests that the inversion evolved before the Lacandonia schismatica lineage diverged. One can only speculate at this point. The future of this species is quite uncertain. Climate change and habitat destruction could permanently alter the conditions so that this plant can no longer exist in the wild. This is further complicated by the fact that this species has proven to be quite difficult to cultivate. Only time will tell. For now, more research is needed on this peculiar plant.

Photo Credit: [1] [2] [3]

Further Reading: [1] [2] [3] [4]

A New Species of Parasite Discovered in Japan

A new species of parasitic plant has been discovered on the Japanese island of Yakushima. A small population was found by Suetsugu Kenji during a survey of the lowland laurel forests that cover much of the island. Despite being an authority on parasitic plants of this region, Professor Suetsugu did not recognize these plants. As such, a specimen was collected for a closer look.

An in depth examination revealed that this was indeed a new species. It has been named Sciaphila yakushimensi in honor of the island on which it was discovered. It belongs to a family of plants called Triuridaceae. They are closely related to the family Alismataceae and many members of this family have foregone photosynthesis for a parasitic lifestyle.

S. yakushimensi is what we call a mycoheterotroph. It parasitizes mycorrhizal fungi, taking the nutrients it needs and giving nothing in return. The fungi themselves are getting their nutrient needs from the trees that grow in the forest. As such, S. yakushimensi could not exist without an intact forest to support its fungal host.

This is the troubling part. Only two populations of S. yakushimensi have been discovered. Its parasitic lifestyle makes it difficult to get an accurate estimation of its numbers. These plants live most of their lives underground, only appearing when it is time to flower. Because of this, researchers are already suggesting that this species be considered endangered.

Sadly, its native forest is under constant threat of logging. Much of this region remains unprotected. Since mycoheterotrophs like S. yakushimensi rely on an intact forest capable of supporting its host fungi, any disturbance that threatens the forest can spell disaster for these parasites. Far from being a detriment to the forests in which they live, parasitic plants like S. yakushimensi can serve as a very important reminder of how crucial it is to preserve entire ecosystems rather than single species.

Photo Credit: Yamashita Hiroaki

Further Reading:

https://www.tsumura.co.jp/english/kampo/plant/090/090_01.html