Fishhook and Pincushion Cacti
- Information on cacti of the genus Mammillaria, with photographs of several species.
- http://www.biology.ed.ac.uk/research/groups/jdeacon/desertecology/fishpins.htm#top

Mammilaria microcarpa
- Photograph and description of the Fishhook Cactus and information on its habitat and range.
- http://www.desertusa.com/mar97/du_fishcactus.html

Mamms on the Mall
- Photo gallery arranged by section and species.
- http://www.cactus-mall.com/tree/

Mammillarias.net
- Forum, comprehensive photo gallery, and collection database. In French and English.
- http://www.mammillarias.net/

Mammillaria
- Descriptions and images for many species.
- http://www.desert-tropicals.com/Plants/Cactaceae/Mammillaria.html

Cacti in Mexico: Mammillaria
- Images of four species.
- http://www.viridis.net/cactus/mexico/mammillaria.html

Mammillaria Discussion Group
- Yahoo group for discussion of Mammillaria and related genera.
- http://groups.yahoo.com/group/Mammillaria/

Mammillaria Society
- Promotes the study of the cactus genus Mammillaria, and also Coryphantha and allied genera such as Escobaria, Thelocactus, Gymnocactus, and Neolloydia.
- http://www.cactus-mall.com/mammsoc/

Mammillaria woodsii
- image
- http://www.dipbot.unict.it/orto/0952-1.html

Mammillaria vagaspina
- image
- http://www.dipbot.unict.it/orto/0999-1.html

Mammillaria umbrina
- image
- http://www.dipbot.unict.it/orto/0987-1.html

Mammillaria hahniana
- image
- http://www.dipbot.unict.it/orto/0981-1.html

Mammillaria elongata
- image
- http://www.dipbot.unict.it/orto/0980-1.html

Mammillaria carnea
- image
- http://www.dipbot.unict.it/orto/0990-1.html

Mammillaria brauneana
- image
- http://www.dipbot.unict.it/orto/0992-1.html

Mammillaria balsasoides
- image
- http://www.dipbot.unict.it/orto/0991-1.html