This article is the first of a series in which I am presenting research on some of the more obscure members of our global ecosystem. I believe that by understanding the complexities of our global flora and fauna, we are in a better position to promote respect and conservancy for our natural resources.

It is clear that our ecosystems are incredibly complex and interwoven. For every small disruption that we make to the health of the planet, there are repercussions to the rest of the ecosystem. And with major disruptions such as climate change, the effects on our ecosystems is unparalleled and potentially catastrophic.

Hence, in this series, I will ask the question, who is this obscure representative of plant or animal life, and how does he fit into the larger ecosystem that we need to protect? So I begin with the lowly liverwort.

What is a liverwort? It is a type of plant life with the following taxonomy:

Kingdom: Plantae

Division: Marchantiophyta

Class: Marchantiopsida

Order: Marchantiales

Family: Aytoniaceae

Genus: Asterella

They are called "liverworts" for their liver shape. They constitute an entire group of plants, in the same way that ferns, mosses, or seed plants do. The taxonomy reference to "Marchant" is for the French botanists Jean and Nicholas Marchant who studied them in the 17th century. They are also called "hepatics". They are characterized as "bryophytes" and "embryophytes". This means they are non-vascular, land plants. They lack most of the characteristics of what we usually associate with plants.

Non-vascular means that they do not have a vascular system. In other words, they do not have xylem and phloem. Instead, they use simple tissues to move water. Also, they do not have roots they attach with single cells called "rhizoids". Liverworts do not have true leaves either. Their "leaves" are just single sheets of cells. They have no cuticle cover or stomata openings. These evolved later as land adaptations. They have a two-stage life cycle. This include asexual spores and sexual gametes.They do not have fruits or seeds.

Liverworts are a very early type of plant, and their claim to fame is that they were the first land plants. They date to the Mid-Ordovician period. That means that liverworts are around 470 million years old. They are more organized than algae. They left the algae behind and developed a functional structure, which was more complicated compared to the algae.

Ancient liverwort fossils are the earliest known evidence of land plants. These fossils of "cryptospores" were found in Argentina and date around 470 million years ago. This discovery was made in 2010, in a rocky area of Argentina. The previous find was dated 10 million years later, in Saudi Arabia and the Czech Republic.

As their name implies, liverworts are not glamorous. They live under the radar and are not known for their economic and societal impact. Some people use liverwort as a natural herb, but it is not known to be safe. However, in the ecosystem they play a role in providing shelter for other life, and in retaining water and stabilizing surfaces.

The evolutionary importance of liverworts is in their being the earliest land plant. From them, you can see how land plants have evolved. For example, liverworts have no vascular system, no leaves, and no roots. Instead, they handle these functions through simple cells. By comparison, you can see that by plants developing leaves with a cuticle to protect them and stomata to exchange gases, that leaves are an improvement. The same goes with the evolutionary improvements of having a vascular system and roots instead of simple tissues. Now they are off to the side with the non-vascular plants, while the vascular plants have shown more evolutionary growth.

There is a variety of liverwort where I live called Asterella Californica, and I am on the look-out for this worthy fellow. In California this liverwort is widely found, except in the higher altitudes of the Sierra Nevada, Klamath Mountains and Lassen County Great Basin. It is a larger type of liverwort, about 1.5-2.5 mm diameter. 

In conclusion, non-vascular plants like the liverwort are fairly primitive, and most plants we think of today are vascular plants. However, they have survived for over 470 million years, so they deserve our care and appreciation for the role they play in the environment.

Resources:

http://nathistoc.bio.uci.edu/plants/Bryophytes/DSC_0080b.jpg

http://ucjeps.berkeley.edu/TreeofLife/newsarchive/061303.htm

http://www.geo.fu-berlin.de/en/v/geolearning/gondwana/media/Gondwanamass01normal.gif?width=930