Mammillaria of the Month

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Mammillaria insularis

Photo: Plant in Cultivation: Copyright of Chris Davies 2009

Mammillaria insularis is one of the more showy flowered,  hook spined species in the Ancistracanthae series and comes from the shores and islands around the Bahia de los Angeles region of the state of Baja California Sur.

It, like a number of its fellows, is tricky to grow well, having fleshy roots that simply cry out for a very open compost. Given that and the light hand when watering, it will reward with a show of flowers over several weeks, sometimes flowering again later in the year as an early autumn bonus.

It's stable mate is Mammillaria boolii, which differs mainly in the spination, with the dark and robust central spine of Mammillaria insularis being replaced by a longer, thinner and lighter coloured spine. It also clumps more readily than Mammillaria boolii, and reports of upwards of 100 stems have been made from habitat observations.

As ever with species delineation, it has been questioned as to whether these two represent distinct species, but for now at least they remain separate.However Mammillaria boolii lives on the mainland coastal stretch of Mexico in the state of Sonora, around the San Carlos Bay region, which is a wide separation indeed.