Mammillaria elongata

Name and range

POWO accepts Mammillaria elongata DC., published in 1828. The former combinations Neomammillaria elongata, Krainzia elongata and Leptocladia elongata are synonyms. Its native range extends from Guanajuato to Veracruz in Mexico. The database also records introduction to Spain, separate from its natural area of origin. [2-WWW]

Stems, spines and flowers

The plant forms groups of cylindrical stems. The RHS profile describes individual stems up to about 15 cm high, cream-yellow to brown spines and flowers about 1.5 cm long, pale yellow or tinged pink. Offsets allow the clump to expand gradually and provide vegetative propagation. [1-WWW]

Regeneration of the normal growth form

Papafotiou and colleagues took individual tubercles with a fragment of tissue at the base from the upper, middle and lower parts of stems of two-year-old plants. Culture was carried out on MS with 20 g/l sucrose, at 25°C, with a sixteen-hour photoperiod and 37.5 µmol photons/m²/s. There were 15 or 18 explants per treatment, and the experiment was repeated twice. [Papafotiou et al. 2001, pp. 163–164]

In the normal form, shoots regenerated through callus. With 1.07 µM NAA and 22.19 µM BA, after 60 days shoots formed on 88% of explants taken in October and 35% taken in February. Explants from the upper stem responded better than those from the middle, while basal explants in the comparison described produced only callus. Section position and the previous condition of the mother plant were therefore part of the conditions underlying the result. [Papafotiou et al. 2001, p. 164, Table 1]

Crested form and normal shoots

Explants taken from the crest itself responded differently from sections below it. With 0.54 µM NAA and 0.44 µM BA, all crest sections taken in October initially produced an enlarged cristata shoot. After transfer to basal MS, both crested and normal shoots grew from it. Callus derived from cristata also produced both forms. [Papafotiou et al. 2001, p. 164–167, tab. 2]

Crested shoots shorter than 1 cm rooted at 67% on MS with 0.98 µM IBA. Subsequent acclimatisation of previously rooted shoots gave 90–100% survival. After two years, about 80% of crested plants still retained this form, while normal shoots also appeared in the others. The exact size of the final cohort was not reported. The study did not establish the original genetic change or transmission of the trait through seeds. [Papafotiou et al. 2001, pp. 165–167]

Cultivation and propagation

RHS recommends cultivation under cover in a free-draining cactus substrate, with bright, filtered light and low air humidity. Watering is moderate during growth, and the substrate is kept almost dry in winter. The plant is propagated by offsets or sowing at 19–24°C. These horticultural recommendations describe a different context from MS medium and the laboratory conditions of the regeneration experiment. [1-WWW]

Crested material may produce offsets with different growth organisation. The result of Papafotiou and colleagues supports separately documenting the origin of cuttings and subsequent shoots. Retention of the growth form in one plant fragment and its persistence in later growth are characters that can be followed over time. [Papafotiou et al. 2001, pp. 165–167]

Related articles

Materials from the author's archive

The species also appears in Konrad Szychowski's private material archive. [Schumann 1890, file p. 54] [Anonim b.d.aa, file p. 1]