Knolle

Knolle is a German botanical term describing a thickened underground storage organ that a plant uses to store nutrients and energy. The best-known example is the potato, the edible tuber of Solanum tuberosum. Knollen typically form as tubers, which develop from underground stems (stolons) or from root tissue, allowing perennation and regrowth after seasons of dormancy or stress. In a broader sense, the word covers various tuberous storage organs produced by different plant species.

In everyday usage, knolle most commonly refers to a potato. The phrase “eine Knolle Kartoffeln” or simply “eine Knolle” is common in German-speaking regions when talking about a single potato. The plural Knollen is used when referring to multiple tubers. In scientific or horticultural contexts, knollen can describe tuber-like storage organs in a range of plants, including those formed from roots or stolons, though the exact anatomy can vary among species and is distinguished from other underground storage forms such as bulbs and corms.

Etymology traces the term to the German knolle, meaning a lump or knob, with usage dating from Middle High German. In botanical literature, the term remains a general descriptor for nutrient-storing underground structures, while specific terms like tuber, bulb, or corm are used to denote particular anatomical types.