I am in Mexico at the moment, back from an amazing dinner of steak, wine, and assorted organ meats. (I am writing this from my phone so I won't be my usual wordy self). I was speaking with a Mexican colleage and friend, and he told me an interesting story of fnding a seedless guayaba tree.
Several years ago, he discovered that his sister-in-law had a tree which bore seedless guayaba. When asked where it came from, she said that she had bought some seedless guayaba from a street vendor in Zamora, Mexico, and in them she had found a single seed, which she had planted and it had grown into a tree which produced seedless fruit.
My friend and his wife started asking around whenever they were in Zamora, until one day they found a fruit seller who had once sold the seedless guayaba. But alas, he no longer had them. The man who had sold them to him could no longer provide them. But he gave directions to where the man lived.
They drove out to him, and yes, he had once had a tree which produced seedless fruit. But a few years ago it had started producing seeded fruit.
After a little research, the mystery was solved. Turns out, the formerly seedless plant produces no viable pollen. The transformation from seedless to seeded coincided perfectly with the first flowering of some other guayabas the man had recently planted.
When propagated and planted in isolation from other guayabas, it once again was seedless.
Not earth-shattering perhaps, but definitely cool.
(And look...I finally posted! Happy now?)