IAS Aroid Quasi Forum

About Aroid-L
 This is a continuously updated archive of the Aroid-L mailing list in a forum format - not an actual Forum. If you want to post, you will still need to register for the Aroid-L mailing list and send your postings by e-mail for moderation in the normal way.

  Hybrids?
From: "Julius Boos" <ju-bo at msn.com> on 2007.02.24 at 07:01:52(15336)
Reply-To : Discussion of aroids
Sent : Friday, February 23, 2007 6:34 PM
To : aroid-l@gizmoworks.com (Discussion of aroids)
Subject : Re: [Aroid-l] Philodendron 'Santa Leopoldina'

I don`t believe that anyone denys that there are 'natural hybrids' in
nature. BUT---'mother nature' usually makes these 'natural hybrids' a
rare occurence, and in many cases a Biological dead-end. Think about a
mule (donkey X horse). In other hybrids, there is no or limited fertility
in the hybrid. The statement 'pollen goes wherever it may' is true in very
few cases except wind-pollenated species, it MUST be transported from plant
to plant (or animal to animal), and there are mecanisims to ensure in most
cases that the pollen from one species goes to that species (distinct
different odurs or shape/colors of blooms in plants, different behaviors,
etc. in animals/birds).
But yes, there are 'natural hybrids' that do sometimes occur, even in
aroids!

Julius

+More
From: "D. Christopher Rogers" <crogers at ecoanalysts.com> on 2007.02.24 at 09:58:48(15341)
Howdy!

I am not a botanist, but I am a professional zoologist and a taxonomist at
that. In zoology, hybridizability is the defining character for genera; if
the gametes from two species can form a zygote, whether that zygote develops
into a sexually viable or inviable (sterile) adult, then the two species
belong to the same genus. There are of course separate rules for
parthenogenic organisms. Obviously this definition will not work for plants
where, for example, in the orchids, hybrids between genera, tribes, and
subfamilies occur, even though the plants are from opposite corners of the
globe.

But something that all taxonomists need to keep in mind is that unlike the
species (or specific) designation, which is an exclusive concept, all other
taxonomic categories (genus, tribe, subfamily, family, on up) are inclusive
categories. If we keep emphasizing the differences between groups we run
into the problem of putting each species in its own genus, each genus in its
own family, and so on. At that point the taxonomy become meaningless.

So, in nature there are natural hybrids. This means that there is gene flow
within genera. There are also entities called stabilized hybrids. These are
reproducing populations of hybrids that have a stabilized set of characters,
and are capable of continued existence without input of new genetic material
from either parent taxon. Every once in a while, I hear of a species that
has been discovered to be in actuality a stabilized hybrid of two other
taxa. But they are functioning independently of the two parent taxa.

Stabilized hybrids typically appear not because the two species are
overlapping in distribution, but because they very rarely meet. In someplace
remote to both species, but rarely colonized by each, they have few mate
choices, and often choose the congener. These resulting hybrids often have
all the best characteristics of both parent taxa, maybe giving them the
characteristics they need to survive in a peripheral habitat. This can be a
source of speciation.

I hope my ramblings are of some use,
Christopher

+More
From: don7T1 at webtv.net on 2007.02.24 at 11:45:23(15342)
Julius tanks for the clarification (the ass and the horse) == a mule,
however I also think of orchids where 4 distinct species will cross and
produce viable seed. Cattleya+laliea+brassovola+epidendrum
Don Hudson

+More
From: "Peter Boyce" <botanist at malesiana.com> on 2007.02.24 at 15:32:39(15344)
Curiously, while natural aroid hybrids seem to be not at all common in
nature, Arum seems to be profligate, with the following confirmed (order of
parents is pollen:seed):

A. apulum x A. italicum ssp. italicum (Italy)
A. creticum x A. idaeum (Crete)
A. cylindraceum (syn. A. alpinum) x A. maculatum = Arum x sooi (first
recorded for Hungary but present almost everywhere that the two species meet
in Europe)

A. concinnatum x A. cyrenaicum (Crete)
A. idaeum x A. creticum (Crete)
A. italicum ssp. italicum (also reported as ssp. neglectum) x A. maculatum
(France)

A. palaestinum x A. dioscorides (Israel)
A. purpureospathum x A. concinnatum (Crete)

What is most interesting is the number of hybrids occurring in Crete.

Arisarum also produces a hybrid between A. vulgare x A. simorrhinum, the
swarms of offsprinr of which have variously been used to describe a whole
raft of ssp. and vars and haev been used to taxonomically merge the two
parents under the name A. vulgare. In fact, the parents are very distinct.

Here in Sarawak I know of at least two populations of Alocasia robusta x A.
princeps; and one of A. reversa x A. ridleyi.

Peter

+More
Note: this is a very old post, so no reply function is available.