Neat word: Anastomosis
The other day I came across this word when I was searching for something completely unrelated on the Web of Science.
- a natural connection between two tubular structures, such as blood vessels
- the surgical union of two hollow organs or parts that are normally separate
- the separation and rejoining in a reticulate pattern of the veins of a leaf or of branches
– From the World English Dictionary
So this is a leaf with lots of anastomoses: