ylla's picture

Bladder wrack on a sheltered shore

Observed: 16th October 2011 By: ylla
S159 Neighbourhood Nature - course complete
ylla’s reputation in Plantsylla’s reputation in Plantsylla’s reputation in Plants
Sheltered shore bladder wrack
Species interactions

No interactions present.


AlanS's picture


Spiral Wrack is so named as the stem is usually twisted. Twisting of the frond tips is of no significance.

The paired bladders rule out F. spiralis. (Might be a hybrid though.)


SkryWolf's picture


the bladders seem too small and too many for bladder wrack.

AlanS's picture

Bladders diagnostic

Fucus vesiculosus is the only species with bladders.

It is a variable species, with several named varieties recognised in the past, though to me the bladders look reasonably typical.


ylla's picture

I had read somewhere -

I had read somewhere - although I can't find it now - that there would be more bladders on a sheltered shore. But it is very spirally - I wondered later if it might be a hybrid.


Nature girl's picture


That's interesting what you say about the number of bladders Jen; I wonder if someone has done a scientific study on this or if it was just a casual observation.

As Alan says, it is quite a variable species. This could be to do with the degree of exposure, but also down to other conditions such as how high up the beach it is and what it is in competition with - there are a number of environmental factors which might influence its appearance. I'd be interested to know if this is a hybrid, or if the spiral-like appearance is just caused by these env. factors.


JoC's picture

Fuscus vesiculosus and possible hybrids

There are publications dating from the early 1900s on the degree of vesiculation of Fucus vesiculosus, and it is generally agreed that vesicles develop more in sheltered habitats, which Achadun Bay, Lismore seems to be; vesicles may be entirely missing in exposed situations.
Considerable hybridisation has been reported in the literature between the three common Fucus species of our rocky shores, but I have not seen much recognition of them in ‘species’ lists. I wonder if there are more potential hybrids among the iSpot postings.


Nature girl's picture

Thanks for this interesting

Thanks for this interesting information JoC.