Hematoxylin is the American spelling, haematoxylin the British. This rule
applies to all words derived from the Greek word for blood - such as
hematology / haematology.

The plant source of the dye is - I think - I'm on the road, can't check
references - spelled Haematoxylon campechianum. This is a Linnaean binomial
scientific name, spelled the same way everywhere.

In either spelling, do not confuse the oxidized form hematein / haematein
(hee-ma-TEE-in) with the blood pigment acid hematin / haematin (HEE-ma-tin).

I THINK I have all that right, but I should never pontificate when on the
road without reference books.

Bob Richmond
Samurai Pathologist
Knoxville TN
(currently in Honolulu visiting his 90 year old auntie)