Nichol's Turk's Head cactus (Echinocactus horizonthalonius var. nicholii)

Federal Register | Recovery | Critical Habitat | Conservation Plans | Petitions | Life History

Listing Status:   


General Information

A small, blue-green to gray-green, barrel cactus that is globose. As it grows the cactus will become more columnar. Large individuals can range in height of 16 to 20 inches tall and 5 to 8 inches wide. Individuals are single stemmed with 8 ribs that spiral around the base to the apex. Each areole has three central spines, one black that curves downward, and two red or gray that curve upwards; and five radial spines that are black or partially gray. Flowers are pink to red, and bloom near the apex of the stem. Flowers are 1.5 to 2.7 inches in diameter.

  • States/US Territories in which the Nichol's Turk's Head cactus, Wherever found is known to or is believed to occur:  Arizona
  • US Counties in which the Nichol's Turk's Head cactus, Wherever found is known to or is believed to occur:  View All
  • Additional species information
Current Listing Status Summary
Status Date Listed Lead Region Where Listed
1979-11-28 Southwest Region (Region 2) Wherever found

» Federal Register Documents

Federal Register Documents
Date Citation Page Title
2007-04-23 00:00:00.0 72 FR 20134 20136 5-Year Reviews of 24 Southwestern Species
1979-10-26 00:00:00.0 44 FR 61927 61929 Determination that Echinocactus horizonthalonius var. nicholii is an Endangered Species
1976-06-16 00:00:00.0 41 FR 24523 24572 Proposed Endangered Status for 1700 U.S. Plants; 41 FR 24523 24572

» Recovery

Current Recovery Plan(s)
Date Title Plan Action Status Plan Status
1986-04-14 Nichol's Turk's-head Cactus View Implementation Progress Final
Other Recovery Documents
Date Citation Page Title Document Type
2007-04-23 72 FR 20134 20136 5-Year Reviews of 24 Southwestern Species
  • Notice 5-year Review, Initiation
Five Year Review
Date Title
2009-07-27 Nichol Turk’s Head Cactus 5-Year Review

» Critical Habitat

No critical habitat rules have been published for the Nichol's Turk's Head cactus.

» Conservation Plans

Habitat Conservation Plans (HCP) (learn more)
HCP Plan Summaries
Pima County Multi-Species Conservation Plan, under Sonoran Desert Conservation Plan

» Petitions

» Life History

Habitat Requirements

The cactus is found on limestone substrates along dissected alluvial fans, inclined terraces and saddles, bajadas, and debris flows. The Pennsylvania-aged Horquilla limestone however appears to support higher densities of cacti. The cactus grows in open to partially shaded areas, including limestone outcrops.

Movement / Home Range

The cactus is endemic to the Sonoran desert and occurs in isolated mountain ranges that extend from south-central Arizona in Pima and Pinal Counties to a disjunct location in Sonora, Mexico. There currently four known discrete populations. These populations occur in the Waterman Mountains, on the Tohono O’odham Nation, and in the Sierra del Viejo Mountains. Known populations occur between 2,400 and 4,000 feet of elevation.

Reproductive Strategy

Flowering occurs during mid-April to July, with most blooms occurring in June. Flowers will open midday and close at night, and may open one to three days following a significant rainfall event. The cactus is self-incompatible, requiring pollen from another plant to complete pollination. After pollination, one to five bright pink fruits are produced. These fruits are covered with wooly, white hairs at the apex of the stem. The fruits become dry, and will drop half to two-thirds of their seeds on the ground. Remaining seeds are retained in the apical pit until they are ejected the following year by emerging flowers.


Activities associated with the mining of minerals, use of recreational off-road vehicles, the spread of invasive species like buffelgrass, drought, and habitat disturbance is association with border and law enforcement activities are all current and present threats to the cactus.

» Other Resources

NatureServe Explorer Species Reports -- NatureServe Explorer is a source for authoritative conservation information on more than 50,000 plants, animals and ecological communtities of the U.S and Canada. NatureServe Explorer provides in-depth information on rare and endangered species, but includes common plants and animals too. NatureServe Explorer is a product of NatureServe in collaboration with the Natural Heritage Network.

ITIS Reports -- ITIS (the Integrated Taxonomic Information System) is a source for authoritative taxonomic information on plants, animals, fungi, and microbes of North America and the world.

FWS Digital Media Library -- The U.S. Fish and Wildlife Service's National Digital Library is a searchable collection of selected images, historical artifacts, audio clips, publications, and video.