Created as a submission for CG Challenge #122, "Nature up close". It was both pleasure and pain to make. Pleasure because it is a subject very close to my heart (I used to grow cacti when I was younger), and pain due to the many quirks of particle systems. Also, I couldn't find reasonable textures, so I ended up creating my own.
Blog post: https://honestmisskate.blogspot.com/2018/03/mammillaria-something-ssima.html
As a former cacti collector myself I wholeheartedly approve of this.
The "pleasure and pain" are wonderfully visualized here with the beautiful blossoms and prickly pins.