Mammillaria of the Month

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Mammillaria polythele (concluded).

Mammillaria xochipilli ESP8/102        Photo: Copyright Chris Davies 2009

Continuing the occasional series on Mammillaria polythele, this month's plants are more forms of this variable species. The first plants illustrated is named as Mammillaria xochipilli, and bears the field number ESP8/102. It comes from  from Zimapam, in the Mexican state of Hidalgo. Reppenhagen maintains this name as a good species, although it is not immediately apparent from his Monograph, why this is. Compared to the type there are again, few major differences, mainly in the number of central spines (4-7, typically 6) rather than the 3-4 of the species, but we have seen that variation already in Mammillaria hoffmanniana.

Mammillaria durispina WH79           Photo: Copyright Chris Davies 2009

Mammillaria kelleriana WTH150       Photo: Copyright Chris Davies 2009

The other two plants are respectively named Mammillaria durispina WH79 and Mammillaria kelleriana WTH150, both now subsumed into Mammillaria polythele ssp. durispina.

These plants are quite young, and so haven't yet developed the full spination or wool of the older plants. It can be seen that they differ in the number of spines, but within the range for the species. But as yet the spines do not show any significant adpression to the plant body, which is one of the characteristics that has caused the separation of this subspecies, although they are not quite so outstanding as with the variations seen earlier in this short sequence. However, David Hunt has suggested that this is only "an extreme for of Mammillaria kewensis, itself only a vicariant of M. polythele" and so it may be, depending on where you draw the line between differing degrees of variability.