>I introduced my statement concerning vegetative/generative propagation with
>'as a general rule', meaning there are exeptions. One exeption is - I
>agree with you - P. alpina which is not self pollinating but does not form
>gemmae. P. alpina is a special case as it is the only winter bud forming
>species with perennial roots. In all other species the roots decay in
>winter and the hibernaculum forms new roots in spring. P. alpina forms no
>gemmae in the classical sense but sometimes the central root trunk produces
>one or more sideplants (which are in fact very short stolons) resulting in
>one plant with several vegetative axes. This is in particular the case in
>plants infected by the microfungus _Ustilago pinguiculae_ . These plants
>are very vigorous, have an overaverage size and an overaverage number of
>flowers as they obviously profit from the infection (infected specimens are
>easiliy identified by their violet-brownish pollen).
I have seen several Ustilago pinguiculae-infected P. alpina. Can you really=
=20
say that the plant profits from the infection? Does infected specimens=20
produce any seeds?=20
Is there an article about the growth-increase in Ustilago=20
pinguiculae-infected P. alpina?
>I didn't notice gemmae in P. villosa up to now but you certainly saw much
>more specimens than I. P. villosa makes rather large seed capsules (in
>comparison to the very small plant size) with relatively large, highly
>fertile seeds. This was also observed and described by Casper (Ping.
>monography). As only those seedlings will survive which fall into a
>suitable place in the uppermost Sphagnum layer - not totally on the surface
>(to dry) but not to deep (to dark) - survival may in fact be low. But
>anyhow this old species made it for already a few million years.
Maybe the P. villosa seeds need a small disturbance in the Sphagnum fuscum=
=20
layer to survive and grow. This could explain why P. villosa is found=20
aggregated in small patches and not in seemingly suitable places.
P. villosa grows in the living layer of the Sphagnum fuscum and has to grow=
=20
upwards before expanding the leaves in spring. The plant may appears severa=
l=20
cm away from previous position and any gemmea may grow in the opposite=20
direction, but if you dig them up you will see that they are or have been=20
attached. The fact that the P. villosa plants moves between seasons makes i=
t=20
a pain to follow over several years.=20
Magnus Thor=E9n=20
Plantecology, Department of Ecology, Lund University
Ekologihuset, S-223 62 Lund, Sweden
Tel +46-(0)46-2229311
Magnus.Thoren@planteco.lu.se