Page "Spacer (Asimov)" Paragraph 20

Further, another story within the story arc establishes the Spacers ' mastery of myco-food ( food derived from fungi ), which they then retain all through history up to their inclusion in the Imperium on Trantor in the sector of Mycogen.

The Spacers control of myco-food makes the farming operations of Solaria seem more puzzling, until we remember that Solaria was aberrant even by Spacer standards and remained so in the later book Foundation and Earth as a real example of menace to the Second Foundation itself.