photos: e.bouman, south lake union, 2010

• Did you know:
• That litmus, the dye used to indicate acidity and alkalinity, is extracted from a lichen? (And another lichen fact: A lichen is a symbiotic reaction between fungus and algae. Who knew?)
• That the branch of a tree is buried deep in the tree’s trunk—not some appendage stuck on merely from the bark outward. Knots in lumber are actually slices through the bases of a branch.
• What the word is for the oozing that happens from the stump when a herbaceous stem is severed, or that you sometimes see exuding from leaf margins? It’s called guttation, and is caused by root pressure. (I just love this word, now that I know it.)

from Botany for Gardeners, Brian Capon