Cameron McMaster cameron@haznet.co.za
Wed, 26 Oct 2005 12:54:31 PDT
Rogan wrote:

Many thanks to Cameron and Mary Sue for adding more Disa pictures to
the wiki.  Disa pulchra is a fascinating plant indeed and is a wonderful example
of one plant imitating another (Batesian mimicry). In the wild D.pulchra
flowers at the same time and occupies the same habitats as Watsonia
densiflora and indeed looks very similar when in flower. The story goes
that pollinators attracted to the Watsonia flowers mistakenly pollinate
the disas as well, but receive no pollen or nectar rewards in return. As
far as is known the watsonias derive no benefit from this relationship
at all, but the disas undoubtably do as sooner or later the insects will
be fooled by other Disa flowers and cross-pollination will take place.

Hi Rogan  Thanks to Mary Sue for putting these pictures on the Wicki.  I concur with your story of the ollination of Disa pulchra.  In the Amatola mountains in the Eastern Cape there are two pink subjects flowering together with Disa pulchra in December - both of which fool me from a distance and perhaps fool the pollinators.  The one is Watsonia amatolae, a local endemic related to W. desiflora and the other is Dierama igneum - both are the same height and the identical pink shade.  You will notice from the Wicki pictures two distinct forms of Disa pulchra - the form on Mt. Kemp is quite different in general shape  to the Mt. Thomas form.

The picture of Disa aconitoides is of the one and only plant I have seen of this species which is very rare here.  Presence or absence of Orchids is the  indication of the status of the grassland - they only survive in pristine grassland and are rapidly dissapearing with habitat degradation - see the September issue of the Botanical Society magazine "Veld and Flora" for my article on the degradation of the grasslands on the Amatola mountains.

Anyone wishing to have a complete set of images of the geophytes of the Eastern Cape can contact me privately.

Cameron McMaster
African Bulbs
PO Box 26, Napier 7270
Tel/Fax: 028 423 3651
E-mail: africanbulbs@haznet.co.za
Website: http://www.africanbulbs.com/

More information about the pbs mailing list