Dioon holmgrenii 


Taxonomy [top]

Kingdom Phylum Class Order Family
Plantae Tracheophyta Cycadopsida Cycadales Zamiaceae

Scientific Name: Dioon holmgrenii
Species Authority: De Luca, Sabato & Vázq.Torres
Common Name(s):
Spanish Palma Del Sol (Sun Palm), plumilla

Assessment Information [top]

Red List Category & Criteria: Endangered A4c; B1ab(iii,iv)+2ab(iii,iv) ver 3.1
Year Published: 2010
Date Assessed: 2009-10-31
Assessor(s): Chemnick, J., Gregory, T. & Morales S.
Reviewer(s): Donaldson, J.S. & Bösenberg, J.D.
Classified as Endangered based on an estimated ongoing decline of >50% over three generations. Also qualifies under criterion B due to very small extent of occurrence, small number of locations and ongoing decline.
Previously published Red List assessments:
2003 Endangered (EN)
1998 Vulnerable (V)

Geographic Range [top]

Range Description: This species is restricted to state of Oaxaca, Mexico. Plants occurs to the south west of San Gabriel Mixtepec.
Countries occurrence:
Mexico (Oaxaca)
Number of Locations: 2
Lower elevation limit (metres): 650
Upper elevation limit (metres): 850
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Plants are known only from two (500 and 10,000 plants) colonies.
Current Population Trend: Decreasing
Additional data:
Number of mature individuals: 10500
Population severely fragmented: No

Habitat and Ecology [top]

Habitat and Ecology: This species grows mainly in humid forest dominated by species of Pinus and Quercus. They are found on slopes with a north eastern exposure. Plants often grow in ravines in humus-rich soil.
Systems: Terrestrial
Generation Length (years): 500

Threats [top]

Major Threat(s): These plants are affected by habitat destruction due to agriculture (corn, pastures) and also as a result of over-collecting.

Conservation Actions [top]

Conservation Actions: This species is listed on Appendix II of the CITES Appendices. Plants are protected by local communities.

Classifications [top]

1. Forest -> 1.4. Forest - Temperate
suitability: Suitable  
1. Forest -> 1.5. Forest - Subtropical/Tropical Dry
suitability: Suitable  
1. Land/water protection -> 1.1. Site/area protection
1. Land/water protection -> 1.2. Resource & habitat protection
4. Education & awareness -> 4.3. Awareness & communications

In-Place Research, Monitoring and Planning
In-Place Land/Water Protection and Management
In-Place Species Management
In-Place Education
  Included in international legislation:Yes
  Subject to any international management/trade controls:Yes
2. Agriculture & aquaculture -> 2.1. Annual & perennial non-timber crops -> 2.1.2. Small-holder farming
♦ timing: Ongoing    
→ Stresses
  • 1. Ecosystem stresses -> 1.1. Ecosystem conversion
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

2. Agriculture & aquaculture -> 2.3. Livestock farming & ranching -> 2.3.2. Small-holder grazing, ranching or farming
♦ timing: Ongoing    
→ Stresses
  • 1. Ecosystem stresses -> 1.1. Ecosystem conversion
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

5. Biological resource use -> 5.2. Gathering terrestrial plants -> 5.2.1. Intentional use (species is the target)
♦ timing: Ongoing    
→ Stresses
  • 2. Species Stresses -> 2.1. Species mortality

1. Research -> 1.2. Population size, distribution & trends
1. Research -> 1.3. Life history & ecology
1. Research -> 1.6. Actions

♦  Pets/display animals, horticulture
 National : ✓  International : ✓ 

Bibliography [top]

Chemnick, J., Gregory, T. and Morales, S. 2007. Email received in response to request for information.

Donaldson, J.S. (ed.). 2003. Cycads. Status Survey and Conservation Action Plan. IUCN/SSC Cycad Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Hill, K.D. and Stevenson, D.W. 1998-2006. The Cycad Pages. Available at:

IUCN. 2010. IUCN Red List of Threatened Species (ver. 2010.3). Available at: (Accessed: 2 September 2010).

Jones, D.L. 1993. Cycads of the World. Reed, New Holland, Frenchs Forest, N.S.W., Australia.

Whitelock, L.M. 2002. The Cycads. Timber Press, Portland, Oregon.

Citation: Chemnick, J., Gregory, T. & Morales S. 2010. Dioon holmgrenii. The IUCN Red List of Threatened Species 2010: e.T42129A10660365. . Downloaded on 01 December 2015.
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