>>>Actually, I've noticed that the whole family of plants - kale, broccoli, cauliflower, and yes, the fresh cabbage - taste better when reheated. There's some fermentation going on which improves the taste slightly. Can't pinpoint or even describe the difference, but I sense it every time.
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>>Those are not a family of plants, they are all just different cultivars of the same plant - believe it or not.
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>>http://en.wikipedia.org/wiki/Brassica_oleracea
>
>They forgot bok choy.

Bok choy is Brassica rapa, a different species - a cultivar of turnip.

>It's still a question whether they are or aren't the same plant. The article mentions no "cross" nor "breed", and yet that's, to me, the crucial difference between "same plant" and "different plant". Just like cherries and cherries - they may be the same plant, historically, but sour cherries and sweet cherries can (and do) grow next to each other and you don't get any cross pollination. To me, that's different plants now.

The cherries you cite are actually different species - Prunus cerasus vs. Prunus avium.

The Brassica oleracea cultivars are all the same species, just with genes expressed differently. Long ago some were successively selected for cabbage-like properties, others for broccoli properties etc. Similarly, Great Danes and Chihuahuas are "cultivars" of domestic dogs.