These are cut ends of two banana stems. As you can see, the middle part has grown a little bit. When I saw this, I remembered an ingenious method used by ancient Sri Lankans to calculate a new borns birth time (as most of the people did not have watches or clocks).
The astrologer will visit the place. He will measure the growth of the inner part of the cut end. Using this he will calculate the interval since baby was born & his arrival, thus calculating birth time of the baby.
Another difference can be seen in this ancient practice. Rather than taking the time when the child is delivered, they had considered the time at which the baby had taken the first breath as the birth time. But most of the time there is only a few seconds difference between these two.