Mammillaria haageana

Accepted name and scope of the line studied

The accepted species name is Mammillaria haageana Pfeiff. POWO recognises M. haageana subsp. haageana and subsp. vaupelii. M. san-angelensis and M. haageana subsp. san-angelensis are synonyms of the nominate subspecies. This treatment organises the names while preserving the origin of the particular research material. [2-WWW] [2-WWW] [2-WWW]

The natural range of the species in Kew's database extends across Mexico from Guanajuato to Veracruz and Oaxaca. The series studied by López-Ruiz and colleagues came from a line maintained at the UNAM Botanical Garden, descended from former plants of Pedregal de San Ángel in Mexico City. The developmental data below concern this material, described as M. san-angelensis. [2-WWW] [López-Ruiz et al. 2026, POWO. López-Ruiz et al., pp. 1327–1329]

Stem, areoles and sexual reproduction in the material studied

The plants have a tuberculate stem with a sunken apex sheltered by spines and hairs. The spine-producing part of the areole occupies the tubercle tip, and the floral region its base. Flowers in the material studied were bisexual and formed a ring around the upper part of the stem. The authors described a highly branched, shallow root system and fruits containing up to twenty seeds about 1 mm long. [López-Ruiz et al. 2026, p. 1327, 1329–1330, ryc. 1]

The four-year-old plants studied had a mean stem width of 28.6 ± 2.4 mm and length of 28.0 ± 2.8 mm. They were capable of flowering under greenhouse conditions. This result applies to the age, material and conditions presented in the paper. The description does not establish the maximum size of the whole species or a universal age of first flowering. [López-Ruiz et al. 2026, p. 1332–1333, tabela 1]

Seedling and apex development

One day after germination, the shoot meristem lay between the closed cotyledons and had two recognisable layers. After three days, tubercle primordia and a third layer appeared, and after seven days the first spines were visible. Over time, the areole-bearing part of the stem elongated above the hypocotyl region. This sequence describes the formation of the characteristic stem from the early seedling axis. [López-Ruiz et al. 2026, p. 1330–1334]

The mean width of the meristem dome increased from about 102 µm on the first day to about 212 µm after ninety days and 772 µm after four years. Measurements included 3–7 meristems per stage. Larger mean stem dimensions corresponded to larger mean meristem dimensions. The analysis was based on groups of plants of different ages, while the genetic and hormonal causes of the changes identified remained to be determined. [López-Ruiz et al. 2026, p. 1329, 1333–1338]

Warunki procedury siewu

In the experiment described, seeds were soaked in water for 48 hours. They were sown in a closable container that let light through, with a mixture of soil and two types of volcanic material. The chamber maintained 28°C, twelve hours of light with a photon flux of 112 µmol m⁻² s⁻¹ and twelve hours of darkness. Germination was identified by the appearance of the radicle. The paper does not compare temperatures, mixtures or soaking times, so this procedure is a documented way of obtaining the series used. [López-Ruiz et al. 2026, p. 1328]

Conservation of material from San Ángel

The authors link the loss of the natural population to habitat destruction and plant collection. The UNAM Botanical Garden preserved a line descended from this site and provided seeds for research and propagation. The loss of this population is information about local history. The broadly accepted species M. haageana has a more extensive range, so the two scopes remain clearly separate. [López-Ruiz et al. 2026, López-Ruiz et al., pp. 1328–1329] [2-WWW] [2-WWW]

Related articles

Materials from the author's archive

The species also appears in Konrad Szychowski's private material archive. [Flores Martínez and Manzanero Medina 2003, file p. 4, 16] [Kaktologia 2009b, file p. 13] [Neciu b.d., file p. 1]