So, I looked at this page, and what struck me was that the part of the plant
to be used in the formula is shown in (rusty) red? Looking at the recipe at
the bottom of the page. Comes of having full color repro's.
That would certainly be consistent with the observation that colour
(usually red) was frequently used as the primary medium for bearing
information in manuscripts pre-1500 or so (cf. "red letter days" are feast
days in almanackes, etc).
.....although it would normally be used rather less carelessly than as seen
in the VMS. :-/