Mammillaria of the Month

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The M. heyderi complex (Part 2)

Mammillaria heyderi, in contrast to some of the species featured here recently, is a well known and frequently collected species.  It occurs from well within the southern US States of Texas, New Mexico and Arizona as far south as the Yucatan peninsular. There are 6 subspecies that form the Mammillaria heyderi complex and this month we will feature the three other subspecies, the first three having been presented last month.

Photograph by Courtesy of John Pilbeam, reproduced from "Mammillaria"             Mammillaria heyderi ssp. hemisphaerica

Mammillaria heyderi ssp. hemisphaerica is a much flatter looking plant than the others in the series and is quite recognisable because of this. It grows from 8 to 12 cm wide with almost no wool in the axils. Radial spines vary frpm 9 to 13, and a single solitary central spine. The flowers are often a dull pink, but can also vary through to cream. This plant is found in Texas and in the Mexican states of Coahuila, Nuevo Leon, and Tamaulipas.

Photograph by Courtesy of John Pilbeam, reproduced from "Mammillaria"         Mammillaria heyderi ssp. macdougalii

Mammillaria heyderi ssp. macdougalii is recognised immediately when it is in flower, as they are yellow in colour, and grows a little larger than the preceding susbspecies being up to 15cm in diameter. The radial spine count is in the same area, typically 10-12, but these are longer, up to 2cm, and one or two central spines a little shorter. It is the most westerly of the complex, coming from Arizona and Sonora.

Photograph by Courtesy of John Pilbeam, reproduced from "Mammillaria"    Mammillaria heyderi ssp. meiacantha

The last of the six subspecies is Mammillaria heyderi ssp. meiacantha, a very well known plant, typically with rather fewer spines that its brethren, although, as if to compensate, these are rather more robust. Like ssp. gummifera, it is very widespread, growing from New Mexico and Eastern Arizona, through West Texas andacross the Rio Grande down to San Luiz Potosi and Zacatecas.