"ex" in authorship was: "fide" in authorship

[SKÁLA Zdenek]

-----Original Message-----
From: Dipteryx [mailto:dipteryx at FREELER.NL]
>I have long wondered what is the background of this botanical usage and how
>it came to be. Does anybody know?

"in":
an author A published a new species Planta virida in a key to local flora which is as a whole edited by an author B. Hence the citation is Planta virida A in B which means that the author of the name is A but the author of the publication is B.

"ex":
an author A published a new species Planta virida in an article but ascribed this name to another author (who e.g. described this species earlier as new invalidly in the herbarium sheets etc.). Hence, in the article the new name appears as Planta virida B but the real author of the desription/name is A. So the citation is Planta virida B ex A which means that the real author is A but the author name appearing in the original publication is B.

>From this follow the shortening rules: the real author name - A in both cases - should be always retained.

Best!
Zdenek Skala