"P van Rijckevorsel" wrote in
:

Gramma schreef
I am not sure if this is the correct forum for this question but
there are surely some botanists who have thoughts on this.

***
One of the prime uses of botanical illustrations is to illustrate
botanical / taxonomic works. These are written by people who will
have special and intimate knowledge of the plants described.
Therefore they will know what parts of the plants it is necessary
to feature, and from what angle, perhaps mounted in a special way.
They will so instruct the artists commissioned to make said
illustrations.

So it depends on the plants portrayed (and perhaps the level to
which knowledge has advanced of the particular plant portrayed. It
does happen that later it becomes known that a feature disregarded
so far by taxonomists is critical, after all).

A common device to show scale is a scale bar (usually a line,
sometimes with short cross lines at either end) that represents,
say, 1cm, 5cm or 5mm in the real plant. If the illustration is
reduced so is the scale bar. PvR


This is true, generally the author of the work requests the
illustration, and specifies the important features.

There at least used to be a certificate program in botanical
illustration offered by the Smithsonian Institute. Don't think that
you are too old for it, Gesina (Nikki) Threlkeld was about 70 when
she got her certificate.

Sean