All Floras      Advanced Search
FNA Vol. 4 Page 255, 256 Login | eFloras Home | Help
FNA | Family List | FNA Vol. 4 | Cactaceae | Mammillaria

12a. Mammillaria heyderi Muehlenpfordt var. heyderi

Heyder’s nipple cactus

Mammillaria applanata Engelmann; M. gummifera Engelmann var. applanata (Engelmann) L. D. Benson; M. gummifera var. hemispherica (Engelmann) L. D. Benson; M. heyderi var. applanata (Engelmann) L. D. Benson; M. heyderi var. hemispherica Engelmann

Stems 4-9 × 4-10(-15) cm; tubercles 9-20 × 3-7 mm. Spines (8-)14-18(-27) per areole; radial spines (7-)13-17(-26) per areole, abaxial radial spines, needlelike, 6-11(-16) mm diam., stiff; central spines 0.15-0.35 mm diam. Flowers 1.8-2.3 × 1.8-1.9 cm. 2n = 22.

Flowering Mar-Apr; fruiting Aug-Mar. Chihuahuan desert scrub, Tamaulipan thorn scrub, and Edwards Plateau, usually limestone and alluvial substrates; 10-1400 m; N.Mex., Okla., Tex.; Mexico (Coahuila, Nuevo León, Tamaulipas).

The spines of Mammillaria heyderi var. heyderi are smaller and usually more numerous than those of the other flat-topped mammillarias in the United States. Individual plants with fewer radial spines, often segregated as var. hemispherica, are frequent in populations of var. heyderi near the Texas coast. Sometimes the central spines are very short. The coarse western var. bullingtoniana has a much narrower range of variation. Reports of M. heyderi var. heyderi from southeastern Arizona and southwestern New Mexico are based on var. bullingtoniana.


Related Objects  
  • Distribution Map
  • Map

     |  eFlora Home |  People Search  |  Help  |  ActKey  |  Hu Cards  |  Glossary  |