Unfortuantely spicules are only found on sponges
http://dictionary.reference.com/search?q=spicules
whereas, stipules the part you are referring to are also called leaf spurs. Their job is to provide a little protection for the pistillate calyxes and the glandular trichomes!!!! So they are a protrusion of the stem allowing the trichomes to grow, which produce the hairs that allow us to decide if the herb superb is ready or not!!!
Marijuana Botany by Robert Connell Clarke might interest you.