Jack Dykinga / Tangled Fishhook Cactus (Mammillaria microcarpa) in full flower after the summer rains, Saguaro NP, Arizona, USA

Jeff Foott / Whipple's Fishhook Cactus (Sclerocactus whipplei) flowering, Arches National Park, Utah

Jeff Foott / Whipple's Fishhook Cactus (Sclerocactus whipplei) flowering, Arches National Park, Utah

John Cancalosi / Fishhook barrel cactus (Ferocactus wislizeni) flowering. Arizona.

John Cancalosi / Fishhook barrel cactus (Ferocactus wislizeni) flowering. Arizona.

John Cancalosi / Fishhook barrel cactus (Ferocactus wislizeni), two flowers with bee pollinating. Arizona.

John Cancalosi / Fishhook barrel cactus (Ferocactus wislizeni) flowering besides Prickly pear (Opuntia sp), in desert. Arizona.

Cyril Ruoso / Cactus (Mammillaria longimamma) south Texas, USA, April.

Chris Mattison / (Mammillaria / Mamilopsis senilis) flower bud pushing through spines, originally from Central Mexico

Cyril Ruoso / Fishhook barrel cactus (Ferocactus wislizeni) flower, Vizcaino Desert, Baja California, Mexico, May.

Cyril Ruoso / Fishhook barrel cactus (Ferocactus wislizeni) close up of flower, Vizcaino Desert, Baja California, Mexico, May.

Cyril Ruoso / Fishhook barrel cactus (Ferocactus wislizeni) close up of spines, Vizcaino Desert, Baja California, Mexico, May.

Cyril Ruoso / Fishhook barrel cactus (Ferocactus wislizeni) in flower, Vizcaino Desert, Baja California, Mexico, May.

Cyril Ruoso / Fishhook barrel cactus (Ferocactus wislizeni) in flower, Vizcaino Desert, Baja California, Mexico, May.

Jeff Foott / Whipple's Fishhook Cactus (Sclerocactus whipplei) flowering, Arches National Park, Utah

Chris Mattison / Cultivated Old lady cactus (Mammillaria hahniana) flower.

Jouan Rius / Fishhook barrel cactus (Ferocactus wislizenii) Saguaro National Park, Arizona, USA, December 2012.

Adrian Davies / Cacti (Mammillaria varieaculeata) in flower in a botanical garden, native to Mexico, Surrey, England, UK, May.

Cyril Ruoso / Fishhook Barrel Cactus (Ferocactus wislizenii) flowers, El Vizcaino Biosphere Reserve, Mexico

Cyril Ruoso / Fishhook Barrel Cactus (Ferocactus wislizenii) flowers, El Vizcaino Biosphere Reserve, Mexico

Cyril Ruoso / Fishhook Cactus (Mammillaria sp) spines, El Vizcaino Biosphere Reserve, Mexico

Kerstin Hinze / Fishhook Cactus (Mamillaria parkinsonii). Northern Mexico.

Daniel Heuclin / Arizona Barrel Cactus (Ferocactus wislizenii) in flower. Foothills of Santa Catalina Mountains, Arizona, September.

Daniel Heuclin / Arizona Barrel Cactus (Ferocactus wislizenii) flowers. Foothills of Santa Catalina Mountains, Arizona, September.

John Cancalosi / Arizona / Fishhook barrel cactus (Ferocactus wislizenii) with fruit in snow after desert snow storm, Sonoran Desert, Arizona, USA

John Cancalosi / Arizona / Fishhook barrel cactus (Ferocactus wislizenii) with fruit in snow after desert snow storm, with Prickly pear cactus (Oppuntia spp) in background, Sonoran Desert, Arizona, USA

John Cancalosi / Fishhook / Arizona barrel cactus (Ferocactus wislizenii) with fruit in snow after desert snow storm with Prickly pear cactus (Opuntia sp) in background, Sonoran Desert, Arizona, USA

Sumio Harada / Fishhook Cactus (Mammillaria sp), Sonoran Desert, Arizona

John Cancalosi / Fishhook / Arizona / Compass Barrel Cactus (Ferocactus wislizeni) Unusual growth form, with fruit, Sonoran Desert, Arizona, USA

Philippe Clement / Compass / Fishhook Barrel Cactus (Ferocactus wislizeni). Organ Pipe Cactus National Monument, Arizona, USA 2007

Philippe Clement / Compass / Fishhook Barrel Cactus (Ferocactus wislizeni). Organ Pipe Cactus National Monument, Arizona, USA 2007

Jack Dykinga / Flowering Pincushion / Fishhook cactus {Mammillaria sp} and Agave {Agave sp} nr Catavina, Desierto Central, Baja California, Mexico

Tui De Roy / Fishhook Cactus (Mammillaria sp) blooming showing characteristic spines, Santa Catalina Island, Sea of Cortez, Baja California, Mexico

John Cancalosi / Fishhook / Compass Barrel Cactus blossom (Ferocactus wislizeni), Sonoran Desert, Arizona, USA

John Cancalosi / Fishhook Pincushion / Tangled fishhook cactus {Mammillaria microcarpa} in flower, viewed from above, Sonoran Desert, Arizona, USA.

Gerry Ellis / Saguaro (Carnegiea gigantea) with Fishhook Barrel Cactus (Ferocactus wislizenii) in the foreground, Sonoran Desert, Arizona

Michael & Patricia Fogden / Fishhook Barrel Cactus (Ferocactus wislizenii) flowering in the Sonoran Desert, North America

Pete Oxford / Arizona / Fishhook barrel cactus {Ferocactus wislezenii} Anza Borrego NP, California, US

Pete Oxford / Arizona / Fishhook barrel cactus {Ferocactus wislezenii} Anza Borrego NP, California, USA

Jeff Foott / Whipple's Fishhook Cactus (Sclerocactus whipplei) flowering, Arches National Park, Utah

Richard Herrmann / Cactus (Mammillaria neopalmeri), San Benito Island, Baja California, Mexico

Claudio Contreras / Fishhook cactus (Mammillaria poselgeri) with San Jose Island beyond. El Pardito Island, Islands of Gulf of California Protected Area, Sea of Cortez, Mexico. May.

Jack Dykinga / Barrel cactus (Ferocactus wislizeni) and Prickly pear (Opuntia sp) charred by Big Horn Fire, a wildfire caused by a lightning strike on 5th June 2020 which burnt for six weeks engulfing 120,000 acres...

Jack Dykinga / Barrel cactus (Ferocactus wislizeni) charred by Big Horn Fire, a wildfire caused by a lightning strike on 5th June 2020 which burnt for six weeks engulfing 120,000 acres of Sonoran Desert. Catalina St...

Jack Dykinga / Barrel cactus (Ferocactus wislizeni) with singed skin and spines burnt off by Big Horn Fire, a wildfire caused by a lightning strike on 5th June 2020 which burnt for six weeks engulfing 120,000 acres...

Jack Dykinga / Barrel cactus (Ferocactus wislizeni) with singed skin and spines burnt off by Big Horn Fire, a wildfire caused by a lightning strike on 5th June 2020 which burnt for six weeks engulfing 120,000 acres...

Jeff Foott / Strawberry cactus (Mammillaria dioica) flowering. Central Baja California, Mexico. March.

Jeff Foott / Strawberry cactus (Mammillaria dioica) flowering, Central Baja California, Mexico. March.

John Cancalosi / Desert vine (Janusia gracilis) with Fishhook barrel Cactus (Ferocactus wislizeni) Sonoran Desert, Arizona, USA. August.