Toxicity is noted only where a source states it. No note here is not a finding of safety.
Sources: Plant Finder — Missouri Botanical Garden; GBIF Backbone Taxonomy — Global Biodiversity Information Facility; Seed Germination Theory and Practice, 2nd ed. — N. C. Deno.
This source reports three treatments. All are shown.
Protocol 1
DerivedN. C. Deno, 1993
Difficulty ModerateRated by us, not by the source.
1
Clean the flesh off the seed
The seed sits in an oily red berry. Wash it daily, briefly, with detergent.
2
Sow and cover
No stated waiting before sowing. Germination time not stated; 21 days assumed.
Deno gives no figures in this passage -- only the washing, and the two things that kill the seed.
Protocol 2
DerivedN. C. Deno, 1993
1
Dry storage
Duration: 730 days
Seed stored two years was dead.
2
Sow and cover
about 2 years from start to sowing.
0% germination.
Two years in storage and the seed was simply dead. Sow Magnolia fresh.
Protocol 3
DerivedN. C. Deno, 1993
1
Clean the flesh off the seed
The seed sits in an oily red berry. Wash it daily, briefly, with detergent.
2
Sow outdoors and leave it
Outdoor treatment killed the seeds.
No stated waiting before sowing.
0% germination.
Deno reports this for Magnolia as a whole rather than for this species by name.