Xref: kermit uk.rec.gardening:241133


"Emrys Davies" wrote in message
...
'Jono',

http://www.ppath.cas.psu.edu/EXTENSI...EASE/fern.html

Regards,
Emrys Davies.



"jono" wrote in message
s.com...
Hi, I have two ferns in large containers that I inherited with my
house
a few years ago. I'm sure that they are Dryopteris, and look possibly
like Filix-Max from comparing them with photos.

From coming up over the last 3 months, one of them has
i) developed a black growth on the underside of the fronds
ii) collapsed in structure, so that all the fronds are lying compltely
down. I have always kept them moist, so its not lack of water.

Is this somethign that I can treat, shoudl I cut it back and leave it
for this year, or should I pull it out completely for fear of
contamination with other plants? N.b. it is in an individual
container
so there's no danger of transmission through the soil
--
jono
Jono
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posted via www.GardenBanter.co.uk

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The underside discolouration is most likely their masses of
sporangia. These produce spores that grow into a totally different plant~
the 'prothallus' which is capable of producing gametes that will grow into a
new fern. The diploid fern alternates with the haploid prothallus.
'Alternation of Generations'. These sporangia are very obvious on the
underside of the pinnae of D. filix-mas. The spores are microscopic.
Collapsed, mature, fronds is/are quite normal. You should be able to
see immature fronds forming in the centre with their diagnostic 'crook'
shape.
Keep very moist and shaded.
Best Wishes Brian.