Marchantia berteroana Lehm. & Lindenb.
Common names: umbrella liverwort (Eng.)
Marchantia berteroana is of one the most attractive and relatively large liverworts in South Africa. It thrives in constantly damp, shaded areas.
What is a liverwort? A liverwort is a small leafless, flowerless, spore-producing plant. Liverworts were the first of the early green land plants to evolve (after algae and before the ferns), about 500 million years ago, making them the oldest living land plants! Liverworts are grouped into three main groups according to their structure: the simple thalloid, complex thalloid and leafy liverworts.
Marchantia belongs to the complex thalloid group. The Marchantia thallus (plant body) is a flattened strap-like structure, 325 -925 µm thick, divided into three layers: the upper layer with pores (under a lens it can be seen to be dotted with closely crowded, whitish pores) with smooth, somewhat glossy surface, the middle layer with air pockets and chloroplast-containing cells, and the lower layer that stores carbohydrates. The thallus of Marchantia berteroana is yellow-green to green or reddish-brown, 600-900 µm thick, with branches up to 20 mm long and about 12 mm wide, with wavy margins. The thallus has scales on the lower surface (ventral scales) that extend nearly to the margins, and rhizoids (hair-like structures that act as roots) with which it attaches to its substrate.
The life cycle is divided into two phases alternating with each other:
- the dominant haploid gametophyte phase (with a single set of unpaired chromosomes); actually the flat green plant that you see and which is responsible for all the plant's metabolic functions — photosynthesis, gas exchange and water absorption.
- the dependent diploid sporophyte phase (with paired chromosomes and therefore with twice the haploid number) during which sexual reproduction takes place.
M. berteroana is dioicous, which means that the male and female gametangia (sex organs) are formed on separate plants. The male and female plants can easily be distinguished from each other by their gametangia, which are very distinct structurally and which are produced from the apex of the terminal segment of the main or short lateral branch.
The male gametangia, called antheridia, are stalked, disk-like structures that produce sperms. The antheridiophore (the stalk of antheridium) is about 30 mm long and arises in August. The antheridial disk, on top of the stalk, is up to 10 mm wide and shallowly segmented into 8 or 9 symmetrical lobes which have brownish or colourless margins.
The female gametangia, called archegonia, are stalked umbrella-like structures that produce eggs. The archegoniophore (stalk of archegonium) is about 80 mm long and it appears in September. The archegonial umbrella, on top of the stalk, is called the carpocephalum and is up to 10 mm wide, dorsally (above) with small round median projections, and deeply divided into 9 linear rays. This sporophytic phase begins in the spring and continues through the summer months.
M. berteroana can reproduce sexually or asexually.
In sexual reproduction water is required for fertilization to take place. The sperm cell has multiple flagella (long whip-like outgrowths) that propel it forward to reach the archegonium. When it reaches the archegonium it swims through the neck and fertilizes the egg at the base of the archegonium, and a diploid zygote forms, the first cell of the diploid sporophyte.
This sporophyte phase, totally dependent for its survival on the mother gametophyte, is attached to it by a foot through which nutrients are passed between the two phases. The sporophyte also has a stalk, called a seta, that connects the foot to the sporangium (capsule). Inside the sporangium the spores are produced and among them are yellow-brown, bispiral (in a double spiral) structures, called elaters, whose function is to help in the release of the spores. The stalk is fragile and remains short until the sporangium has fully matured and the spores are ready for release.
Once the sporangium has matured, the stalk elongates by absorbing water, stretching its cells, growing taller so that it reaches high above the mother gametophyte. The sporangium then breaks open exposing the spores and the elaters. The elaters wiggle, stretch and bend according to the humidity in the surrounding air, thus aiding spore dispersa, after which the fragile stalk disintegrates. This is a very short process. A magnifying glass might come handy if you are lucky enough to see this fascinating process happening right before your eyes.
For asexual reproduction to take place the plant produces special fun-to-look-at cup-like structures, called gemmae cups, located on the upper surface of the gametophyte, 4 mm wide and 3 mm high.
Minute, multicellular, disc-shaped structures called gemmae are produced on the floor of the gemma cups, each attached by a minute stalk and showing two lateral growing-points. When mature, the gemmae break away from their stalks. When water or rain droplets hit inside the gemmae cups, they splash out the gemmae which, when landed in favourable substrate (e.g. damp soil), develop directly into a new plant.
Marchantia berteroana is not listed among the threatened liverworts according to the IUCN SSC Bryophyte Specialist Group.
Distribution and habitat
M. berteroana is prevalent in the winter-rainfall region of South Africa in the Western Cape province and the western part of the Eastern Cape. It also grows in KwaZulu-Natal, Mpumalanga and Limpopo provinces which receive summer rain. It grows in constantly moist environments, in fresh water, waterfall splash zones, forest floors and stream banks. Liverworts do not grow in salty aquatic habitats and few grow in water-limited microhabitats, e.g. rock surfaces.
Derivation of name and historical aspects
The word wort refers to a plant and liver to the fact that the early herbalists believed that the structure of this plant resembles a liver and presumed that it could be used to cure liver ailments. Liverworts are also referred to as hepatics, from the Latin hepaticus for belonging to the liver. The family name Marchantiaceae refers to those liverworts with prostrate and usually dichotomously (into two) branched thalli. The genus name Marchantia was first used by the French botanist Marchant in 1713 in memory of his father (Campbell 1965). The specific name berteroana was named after Carlo Giuseppe Bertero, a 19th century Italian physician and botanist. There are five species of Marchantia in southern Africa.
Spore and gemmae dispersal is by means of water. The low-lying, flattened structure gives this plant an advantage as it is closer to water sources. Like most bryophytes, the liverworts play a very significant role in various ecological systems. They play a main role in nutrient cycles as effective rainfall receptors and in prevention of soil erosion by binding and stabilising soil. They form a major component of humus. The liverworts are closely associated with climatically sensitive habitats, and thus serve as potential bioindicators of environmental changes in the ecosystem.
Liverworts are of little known economic value. Ancient herbalists believed that the liver-like shape of this plant denoted that it could be used to cure liver ailments according to a philosophy called Doctrine of Signatures. This belief has not been scientifically proven.
Growing Marchantia berteroana
Liverworts are best used in rock or shade gardens, in frequently moist, humus-rich soil and in partial to preferably full shade. Some people see the liverworts as weeds but they are in fact a wonderful ground cover.
High humidity suppresses gemmae cup production in M. berteroana and high temperaturez (ca. 15°C) promotes production of more gemma cups (Chopra & Kumra 1988). In her experience with growing Marchantia plants, Martin (pers comm. 2012) states that if exposed to direct sun on a hot day, the trays of her Marchantia plants turn brown in an afternoon and do not recover. She therefore supplements rainfall with 2-5 minutes of three different watering sessions each day during spring, summer and autumn. Her supplemental watering is sporadic in the winter due to freezing conditions as it seems that liverworts tolerate freezing conditions well. She is always happy to share her joy of gardening with bryophytes and is writing a book on moss gardening which will include mention of liverworts as well.
- Campbell, E.O. 1965. Marchantia species of New Zealand. Tuatara 13 (2): 122.
- Botany Department, Massey University of Manawatu. http://www.nzetc.org/tm/scholarly/tei-Bio13Tuat02-t1-body-d6.html.
- Chopra, R.N. & Kumra, P.K. 1988. Biology of Bryophytes. New Age International Publishers.
- How to Grow Liverwort.http://www.ehow.com/how 11404964 grow-liverwort.html#ixzz1oFmBq1l4.
- Martin, A. 2012. Mountain Moss Enterprises, North Carolina, USA. http://www.mountainmoss.com/blog.
- Perold, S.M. 1999. Flora of southern Africa. Hepatophyta 1 (1): 84-95.
- Quick Hepatica Growing Guide and Facts http://www.plant-biology.com/Hepatica-Liverwort.php.
- The Art of Growing Liverworts http://www.gardeningtipsnideas.com/2010/06/the art of growing liverworts.html.
Pretoria National Herbarium
Plant Type: Ground Cover
SA Distribution: Eastern Cape, KwaZulu-Natal, Limpopo, Mpumalanga, Western Cape
Soil type: Sandy
Gardening skill: Challenging