wudsia

Written from the sound alone, wud is a fair attempt. The vowel in wood is short and clipped, quite unlike the long oo of moon, and a single u catches it better than a double o does. English spelling makes no distinction between the two, which is why book, food, blood and door all use the same pair of letters for four different sounds. The fern's name is not spelling the vowel at all, though. It is spelling a man named Woods.

One vowel sound that English can write several different ways.