Scouring rush, Equisetum hyemale, which ought to be called "tube fern" because it is quite closely related to ferns, beares its spores in sporangia at the edges of hexagonal sporophylls that are arranged in a cone-like stobilus. Spore release and dispersal is aided by appendages called "elaters" that unfurl with changes in humidity.
![](https://i.ytimg.com/vi/z33aCPuTmTQ/maxresdefault.jpg)