Plants of hybrid origen

Donald Barnett
Mon, 14 Jun 2010 12:49:25 PDT
Plants in question-

I am working on a book in the Las Vegas area and wanted to investigate all
of the rogue names in question in my area.

One name had appeared in the vascular plants of the Spring Mountains,
Opuntia charlestonensis by clokey in 1943. After retrieving the Modrono he
published the name I went and visited the type locality where only 6 plants
were seen along with one Opuntia erinacea. In December 2009 the
CSSA's haseltonia came out and a article on cactus chromosomes in the
southwest had Opuntia X charlestonensis (N=55/2) and gps quardinants where
the plant was cited from. The populations the plants were visited at were
different than the type locality. I talked to Marc Baker who wrote the
article and he reassured me it was a hybrid. So I visited the site and the
plants match up perfect. Very similar to the type only one of the parent
plants was found at the location. The hybrid (O. charlestonensis) made
up 95% or more of the prickly pears on the hillside. Being that there is
only one other prickly pear found in the general area it must be the
other parent, Opuntia phaecantha (N=66). So Opuntia charlestonensis is a
hybrid of O. phaecantha and O. erinaceae.

At both of these sites the plants were producing flower and seed like a
normal species would. I collected a few seeds and germinated several of
these plants. The seeds came off of a few different plants. The location in
which Marc Baker targets as Opuntia charlestonensis is very healthy and
growing in size. The plants were extremely uniform. The spine length
average, areole distance, pad shape and size was all close enough to call
them uniform in Opuntia standards. Since these populations are reproducing
in typical shape and form I am trying to justify these plants as a true
species in our area.

Is this enough information to justify calling the plant:

*Opuntia charlestonensis* CLOKEY 1943  instead of just writing the plant off
as another hybrid.


Donnie Barnett
Las Vegas, Nevada
Zone 8b where the weather is always like walking on the sun!

On Mon, Jun 14, 2010 at 12:09 PM, Jim McKenney

> Donnie, I'm not a practicing taxonomist, but until we hear from one, let me
> hazard an answer. In fact, I've discussed this informally with taxonomists
> in the past.
> The short answer for situations such as the one you described is that the
> population in question is often treated as a species. The plant we call
> Fritillaria eastwoodiae provides a good example. It varies throughout its
> range, in some areas tending towards one purported parent, in other areas
> tending towards the other purported parent. And it is widely regarded as a
> "good" species.
> But the situation is not always so simple. In southwestern Virginia, Lilium
> grayi seems to be in a species-like relationship with local populations of
> Lilium canadense. Elsewhere in its range, Lilium grayi grows in relative
> isolation and seems relatively distinct. Lilium canadense in other parts of
> its range is distinct. But there is an area where the two nominally
> different species behave as a single species. Most taxonomists are
> reluctant
> to combine the two species (although I’ve read that Asa Gray himself had
> doubts that the lily named for him was specifically distinct).
> But there is more to the story. I don't think there is a simple answer to
> this question, in part because it addresses directly points over which
> taxonomists differ: what is the significance of hybrids, what are hybrids?
> One school of thought says that if fertile hybrids occur naturally, then
> that in itself is evidence that the populations involved are in fact
> members
> of the same species (i.e. they share the same gene pool). This school of
> thought views interspecies hybrids with skepticism; it takes the point of
> view that if two populations with different species names interbreed, then
> the taxonomy is bad; they are not different species, they are one and the
> same species, however variable or different in appearance they seem. This
> is
> the team I'm on.
> The contrasting point of view accepts the existence of interspecies hybrids
> as entities nominally distinct from either parent. In the case of plants of
> cultivated origin (garden hybrids), these entities are apt to be named as
> nothospecies (with the name preceded by the times sign, ×). Wild
> populations
> of “hybrids” are typically not given nothospecific designation but are
> named
> according to the usual rules for plant nomenclature.
> There are cases where horticultural and formal botanical procedures either
> clash or seem mutually contradictory. For instance, in the old days,
> hybridists sometimes named their hybrids with Latinized names. Botanists
> seem to have one take on this, horticulturists seem to have another. The
> botanists sometimes use these Latinized names as the formal botanical name
> for all hybrids of similar parentage. Horticulturists tend to use the names
> to identify the original clone of the hybrid (if in fact there was one
> original clone). If, for instance, the original hybrid clone or strain was
> yellow flowered, but subsequent hybridizing along the same lines produced
> red or blue flowered plants, then the practice of formal botany to use the
> same name for all of these is very confusing to horticulturists who
> associate the name with one particular plant.
> Before leaving this topic, be aware that the word hybrid itself is used in
> mutually contradictory senses. Many people use the term hybrid in the sense
> of a cross between two nominally distinct species.
> The Latinized Greek term from which the word hybrid is derived seems to
> have
> had the sense of “mongrel” as opposed to interspecies hybrid, and this is
> in
> agreement with a broader sense of the meaning of the word hybrid which is
> just as prevalent as the interspecies concept: that hybrids are what result
> when two different breeding lines (of the same species) cross. Corn, for
> instance, is generally regarded as a single species, yet most corn grown
> today is of hybrid origin. The hybrids in question are sometimes
> distinguished as F1 hybrids. To the Romans, people of mixed parentage were
> hybrids. In this sense, the puppies from a Dachshund mother and Poodle
> father are hybrids.
> A lot more could be said about all of this.
> Jim McKenney
> Montgomery County, Maryland, USA, 39.03871º North, 77.09829º West, USDA
> zone
> 7
> My Virtual Maryland Garden
> Webmaster Potomac Valley Chapter, NARGS
> Editor PVC Bulletin
> Webmaster Potomac Lily Society
> _______________________________________________
> pbs mailing list

More information about the pbs mailing list