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Bryum caespiticum

Posted: Sun Feb 20, 2011 4:24 pm
by MWP admin
This should be Byrum caespiticium.

Posted: Sun Feb 20, 2011 7:20 pm
by valerandi
Its a Bryum for sure. The capsule however looks more like that of Bryum donianum. Its difficult to see with the photographs but the plants seem larger than the B. caespiticium I am familiar with. The one found in garigue is much more compact. Perhaps the sporophyte has not matured.

Can you please post photographs of (1) the whole leaf showing the shape where the leaf to see where it is widest (2) a close up of the leaf edge (B.donianum has a thicked border) (3) the moss from a further distance away then the first photograph - to get an idea of the size (4) where was it found? garigue/shaded/ locality? (4) what happens to the plant when it dries : does it become spirally twisted? (to rule out B. torquescens and B. capillare)

best regards

Posted: Sun Feb 20, 2011 10:18 pm
by MWP admin
I will follow the instructions given shortly.

In the meantime here is some more information:

It was found lying on Coraline Limestone in a partially shaded area (more shaded than exposed), sheltered by Olive trees and high level of moisture due the presence of dense undergrowth vegetation under the trees namely Smyrnium olusatum (karfus il-Hmir / Alexanders)

The capsules are in the range of (4) 5-6mm long and the seta 20-30mm long. The specimens were lax to each other (not compact) but of course touching and overlapping each other. The diameter of the whorl of leaves (from above) is about 8mm - 10mm (for the larger specimens). Larger leaves 3-mm long. When dry, the leaves become erect and patent to the stem (not to the extent of appressd) though I cannot say that they are spirally arranged. The colour is medium-dark brown (not beige, not very dark).

I am saying all this becasue I have saved the tuft for these 2 weeks. I am not sure if the specimens are dead because they dried, or becasue they did not ike tap water. The capsules did not dehisce and cannot say anything about the sores and peristome.

One problem for this identification was in fact if the border was thick. The image under microscope gae the impresion of a thick margin, but that could be an optical illusion, because the margin is slightly twisted.

I do not think that the it is the B. capillare complex as the leaf apex was not abruptly contracted to a piliferous point, but we better check the photos.


Posted: Mon Feb 21, 2011 10:09 am
by MWP admin
Here's some more photos:

Now I should have replied questions 1,2,3 in this post and 3,4 in the previous.

In my little knowledge, I do not think it is B. capillare group. At first I tghought about B. intermedium because of the 'dark' margin, but as i said that could be jut a revoluted margin, and actually it is not distinct (though I do not know how a distinct margin looks like!)

F'idejk Sherlock holmes!

Posted: Mon Feb 21, 2011 3:29 pm
by valerandi
1) The habitat is not a usual place to find B. caespiticium. I have always found in exposed sunny locations.
2) The size of the leaves are also larger than in B. caespiticium. The habit is also very different (I shall place a photo here)
3) The shape of the leaves is not the same as in B. caespiticium in which the widest part is below the middle.

Bryum donianum is "readily recognisable by the leaves usually widest above the middle and with a stout border confluent with the stout shortly excurrent nerve. It does not have spirally twisting leaves when dry"

The border is composed of long cells. If it was simply recurved the shape of the cells near the edge would be the same as the rest of the lamina. In this case I can clearly see a (typically yellowish) border of long cells. However to confirm Bryum donianum you need to try to see if the border is composed of more than one layer of cells. I am quite confident that you will.

Best regards

Posted: Mon Feb 21, 2011 10:28 pm
by valerandi
Bryum donianum by Michael Lueth


Bryum caespiticium by Michael Lueth

Posted: Mon Feb 28, 2011 10:11 am
by MWP admin
Hi valerandii - sorry for late replies.

Watching those 2 pics, they are so different and for sure 'my' plants look almost the same as B. donianum as you suggested, but an automatic question comes in mind - if they are so different, why the keys uses microscopic and ambiguous characters like the margin of the leaf to distinguish the two, if there are more obvious macroscopic distinguishable features!

I have not visited the population to check again the margins on fresh specimens, but the photos you posted leave (almost?) no doubt.

Well, is doniamum frequent in Malta?

Posted: Wed Mar 02, 2011 12:21 pm
by valerandi
With Bryum I am never too certain. Just this week I found this unusual Bryum;


I thought it would be easy for an expert to recognise what it is given that it is so different from the usual Bryum species in Malta but I had to send it to him anyway for identification (if possible? without any reproductive structures).

The shape of mosses can change greatly if they grow in different environments. It is only the microscopic structure which remains the same. An extreme example of this is the Bryum pseudotriquetrum found growing submerged under ice in antartic lakes. ( ... -Kanda.pdf) The only way they could have identified it was under the microscope.

With your Bryum, although the plant is arguably not B. caespiticium the only way to make sure that it is B. donianum would be to show that it has a border made up of more than one layer of cells.

B. donianum is a frequent moss in Malta. This is why I suspected that you had found this plant.

Posted: Thu Mar 03, 2011 7:11 pm
by MWP admin
Hi Val... as by now you know, I am a quite stubborn when investigating a species, so I went again to Xewkija.

I have fresh material, which probably will remove many doubts. I have photos of the habit, habitat, dry leaves and magnified image of the leaves in situ. The latter show a kind of yellowish thivk border (but sometimes, I am not sure if I am actually seeing it or immagining it!)

The population was a casual find, so I dont expect to find anything special, but its nice to break of from vascular plants!

Yes, mosses are hard bone - good that there are less than 200 species to fiddle with! The are very challenging and keep you awake till late night! Hope your Bryum turns out something important - why dont you wait for the sexual parts to make life easier?

So to recapitulate would you put a stone on this as B. donianum or not fully convinced? :?

Posted: Tue Mar 08, 2011 10:43 pm
by valerandi
If as you describe; your plant

1) does not twist when dry
2) has a thick yellowish border

It has to be Bryum donianum according to my keys.

Yes bryophytes are interesting and can occasionally offer a nice surprise in new discoveries. I had 2 new species for Malta confirmed this week by my Spanish mentor. Quite exciting as you can imagine.

best regards

Posted: Wed Mar 09, 2011 12:05 pm
by MWP admin
Thanks a lot valerandii,

I am also convinced about B. donianum.

Mosses are not well studied and the hard work and eye straining are likely to be rewarded by excellent discoveries like yours. Keep it up and well done.

If you need some 'professional' (kind of!) photos I do them for you with all pleasure.

I have collected 4 random mosses from mgarr ix-xini but i did not have time to analyse. One is a liverwort actually. I am preparing for a botanical trip to Sicily.

Posted: Wed Mar 09, 2011 5:29 pm
by valerandi
I would love to go botanising in Sicily one day. If you visit any streams please keep a lookout for streamside mosses which are the ones which fascinate me the most. In particular :-

1) Barbula bolleana (recorded once as Trichostomum ehrenbergii from Mtahleb pre 1907)
2) Bryum pseudotriquetreum (recorded once as B. bimum from Wied Balluta in the mid 1800s) ... triquetrum

I have searched in vain for these species in Malta. I have non-Mediterranean types of both species but would love to compare growth characteristics with forms from the Mediterranean.

Many thanks
Have a great trip

Posted: Sat Mar 19, 2011 10:50 am
by MWP admin
I came back Monday night but unfortunately in the short time I had, I was absorbed by the vascular flora, and as you can immagine it was rich and very beautiful. I barely had time to visit the city!

I have neglected mosses, ferns and fauna completely, and still working through my photo load of plants.