Which teas have the highest caffeine content?

This article is an absolutely wonderful one in terms of caffeine and tea:
http://chadao.blogspot.ca/2008/02/caffeine-and-tea-myth-and-reality.html

Here is the main finding:

“Actual caffeine level in tea is highest:

• when the tea is derived from buds and young first leaf tips (thus white tea has a high caffeine level)
• when the bush is assamica type rather than sinensis (can be 33% higher caffeine, thus African black tea tends to be higher than China black tea)
• when the bush is clonal VP rather than seedling (can be 100% higher caffeine, thus new plantings in Africa are higher than old seedling plantings in Asia),
• when the plant is given a lot of nitrogen fertilizer (as in Japan), and
• during fast growing seasons"

In tea the caffeine level is highest. But among all types of tea black tea has highest caffeine level.

Guayusa, Mate and Matcha pack a big caffeine punch. More than blacks I think.
Though, nothing gets me more wired on tea than multiple steepings of ripe pu’er.

Consuming a little caffeine through tea is not a bad idea, after all we are enjoying pollution every time while getting from office to home and vice-versa

it is going to depend, practically from plantation to plantation, from year to year, from leaf to leaf, from time of picking to another. Almost impossible to generalize “oh black tea has got more caffeine than green” or whatever. If you got a lab that can measure such stuff then you can declare but only that sample A got more caffeine than sample B. But do not generalize.

That being said, I think it pretty likely that white tea (proper white tea, silver needle or white peony, but necessarily “white tea” bags from lipton or whatever) and gyokuro and matcha will always be caffeine rich. Or maybe I should call it theine – I seriously find different, much smoother, the stimulant properties of tea as compared to say coffee or mate.

I think the real answer is nobody knows. Best to poke around, try lots of things and notice how they effect you.