Friday, 8 August 2008

A Liverwort

.... Marchantia sp.

Yesterday I purchased some native plants for the back yard. Twenty six plants of sixteen species. Nearly all are Tasmanian natives. One exception is the West Australian Hakea elliptica. I didn't read the label. Looking at the leaves I thought I was buying the local species, Hop Bitter-pea, Daviesia latifolia. That may tell you something about my plant ID skills :-) Oh well - I guess the birds will like it.

In any case, I haven't planted them as yet as I've been more interested in what was growing in a couple of the pots alongside the plants. In fact, truth be known, I purchased two Melaleuca ericifoli simply because I was fascinated by the liverworts growing in the pots.

#1 - Liverworts in pot


If there are any ....ummm "liverwortologists" :~) out there, please feel free to set me straight my description below.

There are two main categories of liverworts - thalose and leafy. Mine is thalose.

The main leafy looking part of my liverwort is the gametophyte. Gametophytes come in different forms for different species. In this one it takes the form of a thallus. That is to say it has no arrangement of leaves and stems but consists simply of a flat spreading vegetative body.

The tiny white dots on the upper surface of the gametophyte, when examined under my little microscope are actually barrel shaped pores. Some species have simple holes on the surface but these more complex structures suggest my liverwort belongs to the genus Marchantia. The pores lead to little air chambers below the surface that allow for the gaseous exchange needed in photosynthesis.

#2 - Gametophyte, - Marchantia.sp.


The underside of the gametophyte is covered in a dense mass hairy looking stuff. These are the rhizoids and their function is to anchor the thallus to the soil.

#3 - Lateral view showing rhizoids


This liverwort has two means of reproduction, sexual, and asexual. The asexual is the simplest to explain. See the little nodules on the surface. These will develop into little cups (gemma cups) which contain green disc like objects of about half a millimetre in diameter known as gemmae (singular gemma) . If the gemmae are washed out by rain onto suitable soil, a new gametophyte will grow. You can see a gemma in the next photo. This one has been washed down to the underside of the liverwort.

#4 - A gemma which has been washed down among the rhizoids

Then there is sexual reproduction. These liverworts are dioceous (They have separate male and female plants) so some of those gametophytes will produce male parts and other will produce female parts.

The long stemmed umbrella like structure seen in photo #. are the archegoniophores (female).

#5 - Ventral view of an archegoniophore (female).


The shorter stalks with the star shapes tops are the antheridiophores (male).

#6 - Antheridiophores (male).

The female receptical (carpocephalum) are initially down near the surface and face up. It is not until after they are fertilised that the stems carry them up high. As the grow taller, sporophytes (where the spore capsules are produced) develop underneath each receptical. The umbrella shaped part grows wider and eventually fold under at the edges so the the spore capsules end up underneath (facing down)

The spores are released and the life cycle continues

Well if nothing else, that was a fascinating diversion from planting my newly acquired plants.

References
  • Australian Bryophytes Web Site . 2008. - Australian National Botanic Gardens/Australian National Herbarium
  • Biology 7th Edition - Villee, Claude. 1977. - Saunders



9 comments:

  1. hi Mosura,

    this is absolutely fascinating !!

    The first time I saw the little "umbrella-like" growths was on a granite outcrop in SW WA in 2006. I didn't have the faintest idea what they were. I was amazed when I did a bit of research into them.

    What a fabulous post, and so easy to understand.

    Cheers
    Gaye

    ReplyDelete
  2. Hi Mosura

    I agree with Gaye - felt like I was back in my A level Biology class!! (-:

    ReplyDelete
  3. 26 plants! you must have some garden. Should keep you busy for a while!

    ReplyDelete
  4. I agree with the other comments - fascinating stuff!

    ReplyDelete
  5. Interesting stuff Mosura, I've always been familiar with liverworts but until now knew nothing about them!

    ReplyDelete
  6. Thanks Gaye - "Easy to understand" That's good to hear. I thought I was beginning to waffle.

    Thanks Adrian - Hope it wasn't toooo boring ;-)

    Thanks Warren - You can see part of the backyard here

    Thanks Mick - Yes it is a fascinating but rather complex subject. Wish I had time to dig further into it.

    Thanks Duncan - Yes they're easy to take for granted. I've been meaning to learn a little more about them for many years but for the most part I just tread on them.

    ReplyDelete
  7. G'day Mosura,
    I reiterate, (or is that just iterate?), all of the above. Certainly got your money's worth in that purchase, hey?
    A very enjoyable read.
    Gouldiae

    ReplyDelete
  8. Hi Mosura,
    I know this tremendously late but I stumbled across your blog while looking up liverworts. My mum just brought back a few pots from the council nursery and they are covered in beautiful liverworts. I was wondering what sort of position would they prefer? Sunny or shady? My variety is the leafy liverwort.
    Thanks =)

    ReplyDelete
  9. Not fungi then, obviously! :) Looks like I got my own description wrong, here: http://www.flickr.com/photos/youcantryreachingme/3548045881/?addedcomment=1#comment72157618522206857

    I'll fix it up soon.

    You have a great blog - I look forward to reading many of the entries in detail.

    How on earth did you get so many exceptional bird photos? How long is your lens? What camera/setup do you use?

    Chris.

    ReplyDelete