Astrophytum myriostigma

Sub-globose cactus without thorns. Five-ribbed stems with cushion-like areoles, without thorns. The stems are finely covered with very small white scales which make the epidermis more or less white. The flowers, 4-7 cm in diameter, appear at the apex of the stems and vary in color from light yellow to pinkish-yellow. Species native to central and northern Mexico. In nature it grows on stony and calcareous soils of bushy floodplains, on steep slopes facing east or west (and south-west). It is also found among the thin layers at the foot of mountain ranges. Its distribution is limited by the need for stony or calcareous soils. This calcicole species requires carbonates to integrate the calcium and make the stem more rigid. It prefers very well-drained soil and a sunny or semi-shaded position. Water every 10-15 days in summer but keep dry in winter. Half-hardy.