In the fruiting body of mushrooms and ticks, tubes are a surface structure used to hold and disperse spores. The many small cavities create large surfaces where the spores are exposed to the outside. Tubes occur on basidiomycetes, which thus have basidia as spore-forming organs.
Source
Mylifeatplaytime – Tubes – Anatomy of a Mushroom with Parts Explained 
April 2023, TÄNKOM | Revised February 2024 RETHINK
