Mushrooms are plants in the culinary sense. Like strawberries, blackberries and raspberries are berries in the culinary sense.

“The gang is interned in a North Korean gulag”

I completely agree. It was used in To Sleep in a Sea of Stars by Christopher Paolini. I can’t think of many other works that use it.

Others have answered you question about non-directed nuclear blasts in space already. They don’t work the same way as in atmosphere; lack the blast or the thermal heat, etc. Enter the Casaba-Howitzer, a theoretical nuclear shaped charge that shoots a directed plasma stream at near light speed. This idea came about in the 60s along with nuclear blast propulsion.