Two thalloids in pots – The Common and the Crescent-cup Liverwort

Never go shopping hungry, my partner tends to say! Last time we went shopping hungry, we came back with heaps of delicious things including two little ceramic pots filled with a salted caramel dessert. The dessert was great and the pots are, too. With my recently started hobby of bryo cultivation, I did not have to think long before I came up with a use for them. I filled into them a layer of wet sand and added two common liverworts. I would not mind going shopping hungry again…

Both species that I picked are complex thalloids, and they are easily grown from gemmae. Marchantia polymorpha subspecies ruderalis (the Common Liverwort) has round gemmae cups. Below, I will show it on the left-hand side. The other species is Lunularia cruciata (the Crescent-cup Liverwort) with – who would have thought – crescent-shaped gemmae cups. I will show it on the right-hand side. Both species occur in similar, ruderal (“disturbed”) habitats, and may also be found in flower pots. Both have separate sexes. I hope I will be able to reveal them one day!

Day 0 – Setup

I took one gemma from each of the thalli pictured above and placed them in the centre of small ceramic bowls with wet sand. This may not be a fair comparison as the Lunularia gemma was fully hydrated and ready to go, whereas the Marchantia sample had been sitting on my desk for about one month. But after less than one hour, the Marchantia gemma was fully hydrated, too. This is not a race after all. I am more interested in morphological differences during gemma growth.

Both gemmae seem to have two apical cells at opposite ends. These are the cells that keep dividing, causing thallus lobes to grow. Eventually, these cells will split causing their thallus lobes to split. A first mile stone to look forward to!

Day 3 – Subtle changes

I said before that the Marchantia gemma had re-hydrated within one hour. It has not changed much since then. The Lunularia gemma has started growing two lobes in opposite directions. This all seems to be going very slow, so I have recently increased the light intensity in my experiment.

Day 6 – They are growing

Another three days later, both gemmae have grown!

Day 11 – Marchantia is folding up

It is now more obvious that M. polymorpha is growing, too. Its two thallus lobes are going upwards. L. cruciata, after growing upwards, is folding outwards again. I took two pairs of photos. The top row is from above as before, the bottom row from an angle.

Day 18 – New apical cells

There has been a bit of change since my last update. Both Marchantia and Lunularia have now two apical cells per thallus lobe. That means we can now look forward to these lobes splitting!

To be continued…

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