What The Merchants Want From Other Planets

I am reluctant to leave the Polesotechnic League yet but what can I say about "The Master Key" that I haven't said already? See:

The Master Key
More Details In The Master Key
Aliens And God
On Cain
Space Races
Treacherous Behavior?
The Van Rijn Show

What do human merchants want from Cain?

"'...furs and herbs.'" (David Falkayn: Star Trader, p. 279)

Lupescu of the Peltery wants to buy the furs from van Rijn and even tries to find where the planet is for himself. The herbs are blue-green leaves with ingredients that Van Rijn's chemists have not yet either understood or synthesized. When the narrator tastes them:

"There was a sweet-sour flavor with wild overtones, and the odor went to the oldest, deepest part of my brain and roused memories that I had not known were lost." (ibid.)

Is that possible with plants from an extrasolar planet?

On Ivanhoe, merchants want the adir plant.
On Suleiman, they want the bluejack plant.
On Ikranaka, they want intoxicants, antibiotics, spices and furs.
On T'Kela, they want wine and furs.
On Satan, they are able to synthesize rare heavy elements.
On Mirkheim, they can mine supernova-generated supermetals.