Date: 10 Sep 1998 13:04:21 +0100 From: Loyd Wix <Loyd.Wix@unilever.com> To: cp@opus.hpl.hp.com Message-Id: <aabcdefg2962$foo@default> Subject: P.heterophylla
Dear Nick
>My Pinguicula heterophylla has produced an offset from the tip of an old
>leaf that bent over and touched the substrate. I knew that this
>behavior was common in Pinguicula primuliflora but haven't noticed it in
>any other of my Mexican pings. Is it more common than I realized?
If I understand you correctly your plant produced the off set *after*
the tip made contact with the substrate, could you confirm this please?
If this is the case then your experience is different to mine and also I
suspect Pauls. I grow two forms of this species the 'alfredae' form
which produces new plants from almost every summer leaf and also the
Conception Papalo plants which have never (so far) produced plantlets
for me. The first signs of plantlet development in my experience is the
appearance of a small white dot of tissue on the very tips of the
erectly held leaves. From this first roots develop and then leaves
become apparent. This process occurs without the need for contact with
compost. As new leaves form in the center of the rosette, the old
leaves bearing the plantlets start to arch over until the plantlets make
contact with the compost allowing them to root. Obviously if the pot
diameter is smaller than the diameter of the plant rosette then the
leaves dangle over the edge of the pot and hence the plantlets miss the
compost (though may manage to bridge the gap to reach a neighbouring
pot). There is a tendency for the descending leaves with plantlets to
becoming tangled with moss fruiting bodies which prevent the plantlets
from making contact with the compost - I use small stones to weigh down
the leaves should this happen to facilitate plantlet rooting. It may be
worth me attempting to artificially bring a leaf of the Papalo plants in
contact with the compost to see if this will induce plantlet formation.
In cultivation I suspect that humidity levels have much to do with how
successfully the plantlets on the 'alfredae' P.heterophylla develop. I
would expect low levels of humidity would damage the emerging roots of
the plantlets.
>The behaviour you noticed is "normal". In the wild, most examples of
>this plant normally produce no such daughter plants. However, a small
>percentage of plants do have this capability. It is clearly a normal
>mutation that occurs and reoccurs spontaneously.
Paul, do you have any data on this? I suspect the 'alfredae' material
originated from Alfred Lau, does anyone know the location for these? It
would be interesting to know if this is a characteristic restricted to
certain locations or whether 'a small percentage' of plants at all
locations exhibit this. Certainly Casper mentions a number of stations
for this species in a couple of Mexican states, though I can not see the
presence of plantlets on the photograph of the P.heterophylla herbarium
sheet at the back of his monograph, and if I have understood the Latin
and German texts correctly, he makes no mention of this phenomena.
>You would expect such a mutation to gradually take over as it clearly
>outperforms other plants in vegetative propagation.
Is this phenomena really best described as a mutation? After all as
Nick points out this process also occurs in some of the N.American
species - and we are always exploiting the presence of meristem tissue
in Pinguicula leaves each time we take leaf cuttings. As far as out
performance goes, I was under the impression that the Papalo plants were
more commonly in cultivation in the UK due to large numbers of plants
being raised from seed. I have never seen the flowers of the 'alfredae'
plants so no seed.
>In the wild, the natural habitat is a calcareous soil (this species
>actually prefers calcium in the soil), a hard soil, and therefore rarely if
>ever do the plantlets root.
However the soil cannot be so hard that seedlings cannot gain a foot
hold - I grow my plants in a compost of crushed tuffa and the plantlets
don't have problem rooting to this. Isn't there also an analogy with
P.vallisneriifolia who's hibernacula develop on stolons, and also an
inhabitant of calcareous conditions (Cliffs).
>Anyone unfamiliar with this plant can see an example of it in Carnivorous
>Plants listed as P. alfredae (yes, I know I know!)
The plant certainly has a very odd appearance, when viewed from the side
SciFi fans would notice a passing resemblance to the Babylon 5 'Shadow
ships' - all awkward and spidery.
>Sorry, I don't know if photos of this plant can be seen on Barry's excellent
>web site. Long time since I looked!
I have photos which I have considered submitting to the database but it
is not the most tidy of plants and my photographs could have been
better. I can certainly try taking some new ones also some macro shots
of the plantlets. I am mainly using slide film at the moment so it
would be useful if anyone could volunteer the services of a slide
scanner.
Finally, does anyone know if the related P.parvifolia is capable of forming
plantlets like P.heterophylla, though I suspect that this other thread leafed
species is not yet in cultivation.
Kind regards
Loyd
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