Everybody should be given the chance to try 红菜苔 (Hóng Càitái) or 紫菜苔 (Zǐ Càitái). It's a very Wuhan-local vegetable that is arguably the best green vegetable I've had in my life. It's called "purple cai-tai" in English (very helpful that!) and has the scientific name Brassica campestris L. or Brassica rapa var. purpuraria.
Unfortunately you're not likely to ever try it, even though it is one of the greatest foods on the planet. See, it really only grows in Wuhan, specifically. Indeed the best of it grows on a SINGLE HILL in Wuhan (the one occupied by Baotong Temple). But the medium-grade stuff itself is really good. Every attempt to grow this vegetable outside of Wuhan, and specifically Hongshan district of Wuhan, has failed. The plants are shrivelled, tough, and bitter. There's something in the Wuhan terroir that takes a kind of lame plant and turns it to ambrosia.
Proper caitai is a dark leafy green with tender stalks that have a purple or red hue with little florettes at the end rather like rapeseed plants. In flavour they're like all the best parts of asparagus (dark, nutty flavour) without any of the bad parts (bitterness) with added sweetness and a distinct umami note. The stalks are super-tender when prepared but not soppy (like overcooked asparagus).
You may think I'm overselling this plant, but how many humble leafy greens got the status of "Golden Palace Imperial Vegetable"? The caitai grown in Baotong Temple was considered such high quality it was reserved for the Imperial Court in the Qing Dynasty. (Note: this is, to my knowledge, the only leafy green that got this level of recognition.) Trying to get any of it to go anywhere beyond the Court was death penalty territory.
And honestly? Given how good the mid-quality range is? I can understand the rule.