two changes at once
keilantes
Two Greek letters have gone missing at once: ch and th.
two changes at once
Both of the h's in cheilanthes are doing the same job. Each marks a Greek letter that Latin could not write with one character, so it used two. Take the h out of ch and you have written the k sound honestly. Take it out of th and you have written the t sound honestly. Both are honest and both are wrong, and the word needs its h's because it is being copied out of another alphabet rather than spelled from scratch.
The class
Two separate decisions about the letters, both made at once.
Same name
Other spellings recorded for cheilanthes
The name