two species, six varieties, one difference
Built as a memo rather than a table: the thing worth hanging it up for reads across the room, with the full reference in smaller type below it.
Three sizes in one archive — from a sheet on the fridge to a poster on the wall.
Caffeine as a percentage of the bean’s dry mass. Altitude above sea level.
Arabica is not an older or more "noble" species but a natural hybrid: robusta once crossed with another wild species, and the offspring took a full chromosome set from each parent.
That is why arabica has 44 of them rather than the 22 every other coffee has. The doubled set makes it self-pollinating — the flower fertilises itself, and a variety stays that variety without outside pollen.
The same fact explains its fragility: all the world’s arabica descends from a handful of plants, so genetically it is almost one plant, and what kills one kills all.
Why the numbers can be trusted. Every countable number here is computed from data rather than typed in, and the sheet must pass 2 independent checks before it is allowed to build — how many items there are, the order they come in, and the claim in the highlighted box itself. If one fails, there is no file.
