They called Quartzanthemum seeds.name and they should be called like Quartzanthemum Seeds. I tried to override it with MineTweaker 3, and also with Resource Loader, but none seems to work. I can only fix it by editing this line in the Mod's Core Language file:
item.agricraft:seedQuartzanthemum=Quartzanthemum seeds
to:
item.agricraft:seedQuartzanthemum.name=Quartzanthemum Seeds

Screenshot:

AgriCraft Version: 1.4.0-beta-2

Thanks for the help! If you need forge logs, modlist, or anything like that, tell me.

This is a bug I wasn't aware of, will be fixed asap. Thanks for informing me.