What Type Of Cactus Is This

Which type of Cactus is this?

I agree with others, this is a pincushion euphorbia, not a cactus. Probably Euphorbia enopla, but there are several species which look quite similar to each other, it will be difficult to identify more than the genus without going to more details like flower color, and fruit. It is quite popular for its beautiful and showy appearance.All conditions pertaining to cactus care apply in respect of this plant. More, it is usually quite sensitive to overwatering.

What are the types of cactus?

True cacti all belong to family Cactaceae, itself composed of 127 genera and 1750 known species. Naturally, this implies a significant amount of phenotypical diversity and growing habits. The following are examples of true cacti representing various genera and superficial appearances. All are demonstrably related to each other through DNA analysis and molecular studies, establishing family Cactaceae.Treelike growing habit (Pereskia)Columnar habit, unbranched (Cephalocereus)Short clustered columnar habit (Ferocactus pilosus)Globular habit (Ferocactus echidne)Globular habit, clustered (Rebutia)Epiphytic (Rhipsalis paradoxa)

What type of cactus is this and what is growing off of it?

Oh wow, this is certainly a tough one! I am quite certain that your plant is from the Mammillaria genus, a large group within the cactus family. There are some 200 different species of Mammillaria alone, and they look quite similar.To me, it looks like a Mammillaria karwinskiana. I would certainly help to know what the flowers look like, but yours certainly looks very similar. The common name in English I have found is “Silver Arrow Cactus”Now, what is growing off of it, that is far easier to know!It is a fruit! Your cactus must have flowered during the previous years, probably even last year, since the fruit has not fallen off yet. You can also tell that it had flowers from the dried remains of the flowers that are still visible above the reddish fruit.Mammillaria fruit are often edible, but don’t have much taste to them. You may want to get yours off once it dries to check if it has seeds in it.Mammillarias are rather easy to grow as houseplants, certainly the ones found in the “green” section of Mammillaria as yours.(there is also a “white” section these plants have so many white spines that they cover up the green body)They actually do great outside, if you can provide them a protection from heavy, relentless rain. Thunderstorms are very much enjoyed. In winter, they need a place where it never freezes, but still gets somewhat cold and you should not water the plant then, this way you will see it bursting into flowers every year.As an inside plant, water sparingly during the darker winter months, about once a month. Try to get it a few weeks of cool weather outside in early spring to induce flowering.(That other plant on the image edge by the way is a grafted one. The pinkish one is a mutated form of Gymnocalycium, it needs the green partner underneath for survival) It seems that you have an arrangement of different succulent plants, they all take well to the above mentioned conditions. Just be careful with the water, you have a lot of soil in that pot. Only water when it has had a chance to dry out.Good luck with your plants!