“We sat under an old thorn-tree
And talked away the night,
Told all that had been said or done
Since first we saw the light.”
There’s a science fiction book titled “Firethorn”. Sounds like an interesting story about a young girl who studies the arts of healing under the wing of a herbalist and when trouble falls upon her she flees to the woods. There nearly starving in the harshness of winter, she eats some dangerously toxic berries which turns her into something else. Scifi.com
Also called nanakamado ナナカマド（七竈）. Distribution: Found in Southern China (Southeast Asia) or southern Europe. Ubiquitous in private Japanese gardens red and yellow berry varieties sometimes twined around each other.
However, according to Wikipedia, “Pyracantha berries are not poisonous as commonly thought; although they are very bitter, they are edible when cooked and are sometimes made into jelly”