Natural pollination...?

[Gwenchanter]

Isn't the definition of a species a group of organisms which can produce viable offspring? If orchids can have interspecies crosses.. doesn't that suggest there is something wrong with the taxonomy? I also recall something about the number of chromosomes for each species being unique. Perhaps that is not true of plants because of polyploidy?

[maitaman]

No. A species is defined by characteristics of the plant and flower. Orchids can cross even inter-tribally (Cstm. X Cym.). Polyploidy can accent those characteristics (often detrimentally) but does not change the basic structure.
The bit about viable offspring came about because so many other families in both plants and animals do not GENERALLY produce viable offspring.
Personally, I think they're going much too far with orchids lately, making genera out of what should be varieties. In some cases it's plain ridiculous. L. purpurata is now a Sophronitis? Gimme a break!

[Gwenchanter]

Yeah I have to agree. I mean look at dogs. A miniature poodle looks way different from a burmese mounatian dog and yet they are the same species. If they were orchids they would at least be different genra or maybe even different tribes!

[Tindomul]

Many plants have simply refused to read the bio text book and don't know they are not supposed to have viable offspring with other species or genera. Its thorn in the taxonomists foot. But what can you do? Go by morphology. In nature, would the plants
A) be able to pollinate one another successfully via wind or other type of pollinator? Are they found in the same region, geographically, or in the same climate?
B)be able to produce offspring?
C)be able to produce offspring that are viable? In other words, would the offspring find a suitable mate or pollinator?

Dogs are found all over the world today. But what would happen if humans were to suddenly dissappear?
With the considerable geographic Isolation that dogs would experience, some being on Islands, others in each content, then after a few 100 thousand years or so, assuming they survive a humanless world, I would expect them all to evolve into different species.

[Gwenchanter]

Good point Tin, actually now that you mention it, I do recall learning that even if two species could actually mechanically breed, they may not be able to because of things like mismatched breeding times or habitat, and for those reasons, they are still concidered seperate species. I never thought about that with dogs but if left to their own devices I bet they would evolve into seperate species if we stopped forcing them to mate. What a neat thought!