ISI 2023-3. Mammillaria mieheana Tiegel

At first glance, Mammillaria mieheana resembles an albino form of Mammillaria elongata. Of course, it is not completely lacking in pigment, it is just pale by nature, as the spines are light yellowish. The flowers are also yellow, and actually rather showy, despite being only slightly more yellow than the spines. The green, chlorophyll-bearing epidermis is somewhat visible through the dense spination. Betalain pigments are also present, as they are characteristic of the cactus family. However, the betalains are not expressed externally. One only sees a flush of pink in the cortex when cutting the stems for propagation. The nature of the spination is very much like that of the equally uncommon Mammillaria densispina, and the relationship to Mammillaria elongata is also evident in the elongate, though more robust and upright, stems. The species is endemic to the state of Queretaro, Mexico and we offer rooted cuttings of material collected by Woody Minnich at ca. 3000 m in the Sierra Zamorano, Querétaro, Mexico. HBG 134178, $10.