What is "omphalodium"

Omphalode \Om"pha*lode\, n. [Omphalo- + Gr. e'i^dos form.] (Bot.) The central part of the hilum of a seed, through which the nutrient vessels pass into the rhaphe or the chalaza; -- called also omphalodium.

Omphalodium is a genus of lichenized fungi within the Parmeliaceae family. The genus contains about four species found in North and South America.