Spice Bush (Calycanthus) does not have berries. They have a pod that has seeds in it.

http://www.cnr.vt.edu/dendro/dendrology/Syllabus2/factsheet.cfm?ID=485

If this is what you have, they have a strange germination habits. First, they like warm soil, secondly, you may have a few germinate, then a few more a week later, or they may all germinate within two weeks. Usually they germinate sporadically. This has been my experience, and the feedback I've received from the people I've traded seeds with have reported the same thing.

Here is a link that might be useful: Calycanthus pictures

Sorry, what I'm looking to grow is Lindera benzoin. It is a bush that produces red berries that can be used as an allspice alternative. The wood from the shrub is also reported to impart a spicy flavor if soaked and marinated or burned.

~Chills

Have you given them a cold period? I clean the pulp off in the fall and stash the seed in damp sphagnum in a baggie in the refrigerator. They start sprouting over time in spring.

Soeur

Lindera grows easily from seed. Clean all the pulp from the berries, (best if fresh) and mix into moist but not wet milled peat. Put in refrigerator for 1-2 months. Plant and they will generally sprout in 30 days or so.

George