Suleiman III

Suleiman has little axial tilt, therefore no seasons;

bluejack grows all year round in the cool, dry Uplands;

hunters and gatherers pick it, then regularly rendezvous with nomadic herders who barter for the bluejack;

a caravan takes it to the city about twice a month;

Solar, i.e., the Solar Spice and Liquors Company, exchanges Technic goods for bales of bluejack;

four times a Terrestrial year, a Cynthian ship collects the bluejack;

the Cynthians deliver letters, journals, books, tapes and news;

scientists study the planet, hoping to win reputations;

for the factors, like Dalmady, the post is a first step on a career ladder;

plantations would be more efficient but too costly to be profitable.

Poul Anderson goes into considerable detail about how an interstellar economy works.