Dolichothele longimamma may be found growing wild in Hidalgo, Mexico. The spherical body of this cactus is covered with large cylindrical tubercles (mamillae) up to 7 cm (23/4 in) long tipped with areoles bearing 9 to 10 radial spines, about 2 cm (¾ in) long and coloured white or pale yellowish brown, and 1 to 3 central spines that are stronger, more rigid and darker. Thegrow from the axils of the tubercles; usually 2 or 3 appear at one time round the periphery near the crown. They are pale yellow and measure up to 6 cm (2lU in) across. The yellow-green fruit is club-shaped and contains a large number of black seeds.
Besides vegetative propagation by means of offshoots or cuttings (in the case of the species the separate mamillae will reliably form roots), most cacti are generally multiplied from seed.
The seeds require several conditions for germination, namely lots of light (that is why they should be sown on the surface of the compost), moisture and heat (preferably 25 to 30°C [77 to 86°F]). If it is impossible to provide bottom heat and artificial light then it is better to wait until late spring to sow the seeds.
The sowing medium should be free-draining, such as a mixture of 1 part peat to 3 parts sand. The dish containing the seeds should be covered with glass. If glass preserving jars are used as containers, the compost can be sterilized with heat before sowing takes place. After the seeds are sown the jars should be closed tightly to prevent mould from forming in the moist atmosphere and placed in a warm, well-lit spot. When they are sufficiently large the seedlings should be removed from the dish or jar with a wooden peg, taking care to damage the roots as little as possible, and potted up, using the compost recommended for astrophytums. They should be shaded slightly and kept dry for a short while after being moved.