The famous Voynich manuscript (Beinecke 408) Sunflower on f33v may be instead a Pincushion flower (Scabiosa). This would explain the mysterious roots of the drawing.
"This plant has leaves that look like arrow heads. It is called Chenpodium bonus-henricus (Good KingDiane O'Donovan also researched the possibility in her post here and found a lot of arguments in favor of Chenopodiom, although she like the Strawberry Blite version of the plant.
Henry). Chenopodium comes from the term for goose foot in Greece (the leaves sort of look like geese feet)."
One of the most common causes for yellowing leaves is too much moisture or over-watering... Water or air temperature that is too cool can also result in geranium yellow leaves. Geraniums are a warm weather plant and they do not deal with cool weather well.
In the 15th century, beards were once again routinely worn by nobelmen and elders to signify importance, dignity, and advanced age. They were curled with lead iron, parted at the chin, and plastered into submission.
Iron gall inks normally contain iron, sulfur and carbon, and frequently potassium. Small amounts of copper and zinc are little unusual. Sources for these elements may be as minor contaminants in the iron source, or possibly due to the use of a brass inkwell; the actual source is unknown.The copper and zinc may have other sources. How about using of brass mortar to crash the oak galls into ink?
...Get linseed, pound in a brass mortar, make an emulsion therefrom with pure water, boiling it as you do porridge...The physicians also used brass pots, vessels and basins.
...Take a handful of mallows, of snails shells, of pennywort and linseed, pound them in a brass mortar...