Do these two different flowers really mix?

I was going through Bluestone's catelog and they have a beautiful plant that has this description;
HEUCHERELLA Bridget Bloom
Pink, starred white. A cross between Heuchera and Tiarella
Can 2 different species cross? Are there other flowers that will cross breed also?
Kathy

http://www.bluestoneperennials.com/b/bp/HEBBS.html

Kathy,

I don't know specifically about Heuchera and Tiarella, but it isn't unusual for two different species within the same Genera to cross. In some cases, intergeneric crosses are also possible.

MM

There exists a hybrid between an agave and a manfreda.

HI Arenzo,
This is true, but some botanists consider Manfredas to be Agaves anyway. Crosses between genera are not terribly unusual in the plant kingdom and are designated by a lower case 'x' before the name of the hybrid genus. Most commmonly they occur between two genera which are closely related to each other anyway. A classic example is crossing Pachyphytum with Echeveria to produce xPachyveria plants which then possess characteristics from both parent genera.

Part of the difficulty is that a Genus of plants is NOT a natural entity as such, it is more of an observational category. Botanists classify plants by looking at them and grouping plants together which share similar characteristics. What we don't always know is whether those plants are similar because they are genetically related, or because evolutionary pressures in similar environments have ended up producing similar outcomes.

Modern genetic techniques are starting to shed light on some of these mysteries, which is one of the reasons why Latin plant names change from time to time, but good old fashioned observation will still play a part in taxonomy and classification for a good while yet, at least until we can all put a DNA analyser on our own desktops!

Ciao, KK.