16 hours ago
Acorn Plum Gall (Amphibolips quercusjuglans). Inedible. And not a mushroom - or fruit, despite its appearance. These objects are growths induced on oak trees by gall wasps. Their interiors are red and juicy. At the center of each, where the pit of a plum would be, rests a tiny wasp larva. The larva eats the "fruit" of its home as it ages, then chews a hole and departs, leaving an empty husk behind. How wasps induce these growths is a mystery. Though technically parasitic, galls don't seem to harm trees. Now some interesting trivia: A related type of gall - the oak marble gall - was used for centuries in the production of iron gall ink. The earliest recipe for this ink comes from Pliny the Elder, born in AD 23. The ink was used in the production of the Codex Sinaiticus, the oldest, most complete Bible currently known to exist, thought to be written in the middle of the fourth century. Many of Leonardo da Vinci's sketches were drawn with gall ink, too. Its purple-black hue was popular because of its permanence and ease of manufacture. Production ceased in the early 20th century, when synthetic (often oil-based) inks cornered the market. But hobbyists still make gall ink today. The recipe hasn't changed in over 2,000 years.