Colorado hookless Cactus (Sclerocactus glaucus)
Where Listed: WHEREVER FOUND
The Colorado hookless cactus is a barrel shaped cactus that ranges from 1.2 to 4.8 inches (in.) (3 to 12 centimeters (cm)) tall, with exceptional plants up to 12 in. (30 cm) tall. Stems range from 1.6 to 3.6 in. (4 to 9 cm) in diameter. The stems have 8 to 15 (typically 12 or 13) ribs that extend from the ground to the tip of the plant. Along the ribs are areoles (small, cushion-like areas) with hooked spines radiating out (Heil and Porter 2004). There are two types of spines, radial and central, defined by the size and position on the plant (see Figure 1) (74 FR 47112, September 15, 2009). The 2 to 12 radial spines are located around the margin of the areole, extending in a plane parallel to the body of the plant. The radial spines are white or gray to light brown. They are up to 0.67 in. (17 millimeters (mm)) long, and less than 0.04 in. (1 mm) in diameter. The one to five central spines (usually three) are 0.5 to 2.0 in. (12 to 50 mm) long, are generally longer than radial spines, and extend from the center of the areole. The central spines include abaxial and lateral forms. Abaxial spines are typically single, point toward the top of the plant, and are noticeably bent at the tip at an angle usually less than 90 degrees. Lateral spines are usually present in pairs on either side of the abaxial spine, but are more or less straight and diverge from the abaxial spine at an acute angle (usually 20 to 50 degrees).The flowers are usually funnel-shaped, but sometimes bell-shaped. They usually have pink to violet tepals (petal-like flower parts not differentiated into petals and sepals) with yellow stamens (the male reproductive organ of the flower), and are 1.2 to 2.4 in. (3 to 6 cm) long and 1.2 to 2 in. (3 to 5 cm) in diameter. The fruit is short, barrel-shaped 0.31 to 0.47 in. (8 to 12 mm) wide, and 0.35 to 1.2 in. (9 to 30 mm) long.
- States/US Territories in which the Colorado hookless Cactus, Wherever found is known to or is believed to occur: Colorado
- US Counties in which the Colorado hookless Cactus, Wherever found is known to or is believed to occur: View All
- Additional species information
|Status||Date Listed||Lead Region||Where Listed|
|1979-10-11||Mountain-Prairie Region (Region 6)||Wherever found|
» Federal Register Documents
|Date||Title||Plan Action Status||Plan Status|
|2010-04-14||Sclerocactus glaucus (Colorado hookless cactus) Recovery Outline||Recovery efforts in progress, but no implementation information yet to display||Outline|
|Date||Citation Page||Title||Document Type|
|2006-12-14||71 FR 75215 75220||90-Day Finding on a Petition To Remove the Uinta Basin Hookless Cactus From the List of Endangered and Threatened Plants; 90-Day Finding on a Petition To List the Pariette Cactus as Threatened or Endangered||
|2008-03-28||Uinta Basin hookless cactus 5-Year Review|
» Critical Habitat
No critical habitat rules have been published for the Colorado hookless Cactus.
» Conservation Plans
No conservation plans have been created for Colorado hookless Cactus.
» Life History
Populations of Colorado hookless cactus occur primarily on alluvial benches (soils deposited by water) along the Colorado and Gunnison Rivers and their tributaries. Colorado hookless cactus generally occurs on gravelly or rocky surfaces on river terrace deposits and lower mesa slopes. Exposures vary, but Colorado hookless cactus is more abundant on south-facing slopes (Colorado Natural Heritage Program. Soils are usually coarse, gravelly river alluvium above the river flood plains, usually consisting of Mancos shale with volcanic cobbles and pebbles on the surface. Elevations range from 3,900 to 6,000 feet (ft) (1,400 to 2,000 meters (m)) (Heil and Porter 2004). Associated desert shrubland vegetation includes shadscale (Atriplex confertifolia), galleta grass (Pleuraphis jamesii), black-sage (Artemisia nova), and Indian rice grass (Achnatherum hymenoides). Populations also exist in big sagebrush (Artemisia tridentata) dominated sites and in the transition zone from sagebrush to pinyon-juniper (Pinus edulis and Juniperus osteosperma) communities.
Movement / Home Range
Distribution, Abundance, and Trends: Colorado hookless cactus is an endemic plant found in Delta, Montrose, Mesa, and Garfield Counties, Colorado. There are two population centers of Colorado hookless cactus: (1) on alluvial river terraces of the Gunnison River from near Delta, Colorado, to southern Mesa County, Colorado; and (2) on alluvial river terraces of the Colorado River and in the Plateau and Roan Creek drainages in the vicinity of DeBeque, Colorado. These populations may be morphologically and genetically discrete from each other. Introgression with S. parviflorus may play a role in these differences. This issue is being researched by the Denver Botanic Gardens.
Pollination is likely carried out by a broad assemblage of native bees and other insects, including ants and beetles.
» 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.