What is "pithy gall"

Pithy \Pith"y\, a. [Compar. Pithier; superl. Pithiest.]

1. Consisting wholly, or in part, of pith; abounding in pith; as, a pithy stem; a pithy fruit.

2. Having nervous energy; forceful; cogent.

   This pithy speech prevailed, and all agreed.
   --Dryden.

   In all these Goodman Fact was very short, but pithy.
   --Addison.

   Pithy gall (Zo["o]l.), a large, rough, furrowed, oblong gall, formed on blackberry canes by a small gallfly ( Diastrophus nebulosus).