Not your fault. The seed was stored at improper temps or is just plain OLD. Check your source and investigate if this type of seed has possible embryo dormancy. I seed millions of seed per season and 9 times outa 10 it's old.

Assuming you have good seeds, it is possible that your cultural conditions are not correct. The seeds first require a moist stratification (3 weeks to 3 months). I'm not familiar with this seed but is it a hard shelled type of seed/berry? Also, the compost in which you've sown the seed must be kept moist, too. It is possible that the seeds got hung up and couldn't break their seedcoat due to the coat not being soft enough (which is gets from the moist strat and evenly moist soil when sown). I've had seeds put out a root, only to die in the same manner and my seeds were viable. I changed the way I've stratified the seed, while being very diligent in keeping up even moist during the strat time and sowing time. Plus, I also covered the sown seeds with a thin, clear plastic baggie over top of the cell pack to hold in heat and moist under the shoplights. If you have bad seeds, then you have bad seeds. However, bad things happen to good seeds, too. Good luck :)

I looked to see how these might differ from p. hexandrum, and find 'syn. hexandrum'.

Clothiers, suggestions are normally for seeds which have been allowed to dry. "Podophyllum hexandrum, Pour hot water over seeds, let soak 1-2 days until swelling noticeable. Sow at 64-71ºF for 2-4 wks, move 39ºF for 4-6 wks, move to 41-53ºF for germination. Short viable

My climate is much milder than yours, but seeds from my own plants, cleaned of pulp and sown immediately, covered with grit topping and left outdoors will germinate in late winter. Seeds stored until early winter, soaked, then sown and covered with grit, placed outdoors will also germinate in late winter, just a little later than those sown immediately.....in both cases, they are getting a rather extended cold moist period.

I had trouble germinating podophyllum as well. Tried this year with GA-3 and seeds rotted. Am trying agin now.
I have found that some seedlings will only send a root first year and need second cold period to send up leaves. Also for seeds like gingers is very important not to get temps changed fast- meaning you can't put them into to fridge and take it out. They will do much better with oscillating temps outdoor to produce valid seedlings.

I put the flat of remaining ungerminated seeds outside in mid-March to see if the elements could work their magic. It took patience, keeping the flat watered and in shade, but I am happy to report that I have three small seedlings up.

Thanks for your advice.

kms