Penstemon eatoni - the Eaton Firecracker or Firecracker Penstemon

[RickR]

AND since I do have a hybrid between P. cobaea and P. hirsutus var. pygmaeus in my garden, one or both of the parent "species" is actually a hybrid, and not pure species.

[McDonough]

That's so COOL Rick!  I do believe that sometimes it is a matter of bringing things together, things that wouldn't necessarily have the opportunity to be together in the wild, but in garden settings, they can start intermingling in ways that defy common belief.  I have many examples with Allium where the native American A. cernuum and A. stellatum will interbreed with European and Asian species, creating all sorts of interesting "new plants".

[Nold]

So the bottom line for me as a gardener would be, that seed collected in a garden from a known species is most likely to be the real thing. That hybrid offspring are rare.
Did I get that correctly?

Not precisely. There are plenty of plants labeled as true species in the trade that are the real thing.
When plants are introduced into the garden that have, as their ancestor, a hybrid that may have been originally sold as a species, then the possibility for producing a lot of plants that could be described as "garden hybrids" is considerable.
Hybrid offspring in the wild are rare, according to the documents I have. Penstemon species are often sympatric and show no evidence of crossing. Penstemon glaber var. alpinus, P. confertus, and P.whippleanus grow right next to each other on the road to the rock garden on Mt. Goliath, but no hybrids are evident.
If penstemon hybrids are rare in the wild, but apparently common in gardens, that leads me to my next question .....

[Nold]

The next question being, and it's a rhetorical one, if penstemons don'y hybridize in the wild much, but do a lot in the garden, then the obvious conclusion is that the plants are happier in the garden.
The question....and this may be a leap....is, if plants are happier in the garden, what advantage is there to knowing what the plant's native habitat conditions may be?

[McDonough]

The next question being, and it's a rhetorical one, if penstemons don'y hybridize in the wild much, but do a lot in the garden, then the obvious conclusion is that the plants are happier in the garden.

I'm not sure there is such a direct correlation.  In the garden, where one can amass a number of species in a small area, species that would otherwise never have the opportunity to be growing together, then the possibility of hybridization increases many fold.  Each genus of plants then has its own genetic persuasion that might enable or inhibit hybridization.  I'm no expert on Penstemon, but bring together members of Dasanthera within close proximity and the behold the promiscuity.  I have heard that hybridization between sections of Penstemon are highly unlikely.  It contrast, it is interesting that in a huge genus such as Allium, where similarly there are distinct "sections" of the genus that are quite different and separate from each other, studies on the genus have concluded that species from disparate sections of the genus are actually more accepting of hybridization than closely allied species.  I mostly agree with this finding based on personal experience.