You can survey a room to find the plants there. After seeing what plants if any are in the room, identify <plant> to see what kind they are, then evaluate <plant> to find its parts. Once the parts are determined, you can use collect <plant's item> to forage the parts. A plant will only regenerate if you collect all of the items it has to offer, allowing other players coming behind you an opportunity to forage as well.

You can also bundle your finds if the two are identical. The syntax is bundle <item> with other <item> as you hold both in your hands. Bundling makes an item take up less space in your container, and makes it easier to sell in bulk to the herbalist. If you need something you have already bundled, you can unbundle it.

Example: survey
You survey the area.
You notice a short stubby tree.

identify tree
You attempt to identify a short stubby tree.
You identify a short stubby tree correctly as an apple tree.

evaluate apple tree
You attempt to evaluate an apple tree.
You evaluate the parts of an apple tree.
On an apple tree are eight small green leaves, four round firm fruits and six white five-petaled flowers.

collect fruit
You attempt to collect a round firm fruit from an apple tree.
You collect a round firm fruit.

identify fruit
You attempt to identify your round firm fruit.
You identify a round firm fruit correctly as your slightly marred greenish apple.

eat apple
You eat some of your slightly marred greenish apple.