When this Jurassic plant was smothered in molten lava one hundred and eighty million years ago, it was almost instantly fossilised -- in incredible cellular detail. In fact, the fern -- seen here in cross section through the stem -- was preserved right down to the level of chromosomes, which can be seen frozen in the process of cell division.
The sample was collected in the 1960s and left in a drawer at the Swedish Museum of Natural History, but was recently analysed and found to be a rare example of wonderfully detailed preservation. The scientists hope that there may be more, even more interesting, objects preserved in a similar way, too -- just waiting for us to find them. [Science via New Scientist]
Image: Benjamin Bomfleur