Term: microspore: smaller of the two types of spore produced in heterosporous plants; develops in the pollen sac into a male gametophyte
Broader: spore: a small usually single-celled asexual reproductive body produced by many nonflowering plants and fungi and some bacteria and protozoans and that are capable of developing into a new individual without sexual fusion | Unrelated: hydrocyanic acid: a solution of hydrogen cyanide in water; weak solutions are used in fumigating and in the synthesis of organic compounds