Herblore is a skill introduced in version 3.15 of Unreal World. It is the abilty to identify plants and the effects, both raw and boiled.
You will not know what mushroom it is until you try it, or start with that knowledge. For example, if you know what sorrel is, it will show you its effects when you examine it.
effect raw: (effects)
effect boil: (effects)
if you do not know what sorrel is, it would say:
or it may not tell you the effects, if you have never even tried sorrel. The descriptors (odd, coarse, slimy) are randomized with each new playable characters.
A plant's icon will change from white to the complete form when it is known, keeping the player from recognizing it. But the icon will not necessarily change on every area of the world.
To improve your herblore skill,
try an unknown plant or simply use Alt+e on a certain kind of unknown or still-more-to-learn plant in different days and different areas. In some day you will grow the knowledge of it, and also the heroblore skill.