Complex sentence: The method takes its name from the word "stemma" in the meaning of "family tree", which shows the relationships of the surviving witnesses (the first known example of such a stemma, albeit with the name, dates from 1827).
Split into simpler sentences: The method takes its name from the word "stemma". This specific meaning shows the relationships of the surviving witnesses (the first known example of such a stemma, albeit with the name, dates from 1827).