P van Rijckevorsel wrote:
According to Harris & Harris it [spicule] is also used for a small spike
in plants, an outgrowth of the epidermis

Ivan Sache schreef
According to the APS Glossary of Plant-Pathological Terms, spicules are
paired, sclerotized structures that are the male copulatory organs of
Nematodes; or fungal needlelike outgrowths. Rust spores are, for
instance, decorated with spicules, which are believed to help spores to
be attached to host plant surface.

+ + +
Not to mention the medical uses
PvR