Dioon spinulosum
| Dioon spinulosum | |
|---|---|
| Foliage on a young Dioon spinulosum at El Paraíso Zacatal, Oaxaca, Mexico | |
| Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Gymnospermae |
| Division: | Cycadophyta |
| Class: | Cycadopsida |
| Order: | Cycadales |
| Family: | Zamiaceae |
| Genus: | Dioon |
| Species: | D. spinulosum
|
| Binomial name | |
| Dioon spinulosum | |
Dioon spinulosum, giant dioon or spiny dioon, is a cycad endemic to limestone cliffs and rocky hillsides in the tropical rainforests of Veracruz and Oaxaca, Mexico. It is one of the tallest cycads in the world, growing to 16 meters in height. The tree is found at low elevations to 300 meters above sea level.
Dioon spinulosum prefers well-drained soil with regular water. It will grow in soils containing few nutrients, in soils rich in limestone, and on slopes.
Description
Dioon spinulosum may exceptionally reach as much as 16 meters (52 ft) in height, but is more typically 3–6 m (10–20 ft) tall.[2] Mature leaves are numerous and measure 1.5–2 m (4.9–6.6 ft) with 140 to 240 leaflets.[3] The seed cones of the species are among the largest of the cycads.[2] They measure almost 80 centimeters (31 in) in length together with its stem and 30 cm (12 in) in diameter.[4]
Taxonomy
Dioon spinulosum was scientifically described and named by August Wilhelm Eichler crediting William Turner Thiselton-Dyer in 1883. It is classified in the genus Dioon as part of the family Zamiaceae.[5] According to Plants of the World Online it has no subspecies or synonyms.[6]
Names
The species name, spinulosum, means "with small spines" referring to the edges of the leaves.[3] It is known by the common names giant dioon,[7] spiny dioon,[8] and gum palm.[9] In Spanish it is known as Coyolito de Cerro.[1]
Range and habitat
Dioon spinulosum is found wild in the Mexican states of Oaxaca and Veracruz in a total of three locations.[1] It was more widely distributed in the past, but now grows in the lowlands of the Sierra Madre Oriental mountains.[3] It grows on limestone hills and cliffs in the tropical evergreen rainforest there. It can be found at altitudes of 30 to 300 meters (100 to 980 ft) above sea level. It is typically a part of the understory with only a few individuals emerging from the forest canopy.[1]
Cultivation
In cultivation it is slow growing, and has a medium tolerance for salt.[8] It is cold hardy in USDA zones 9B to 11.[7]
References
Citations
- ^ a b c d IUCN 2022.
- ^ a b Norstog & Nicholls 1997, p. 14.
- ^ a b c Jones 1998, p. 174.
- ^ Norstog & Nicholls 1997, p. 278.
- ^ Hassler 2025.
- ^ POWO 2025.
- ^ a b IFAS Extension 2025.
- ^ a b Broschat & Meerow 1991, p. 103.
- ^ Govan & Kahn 2005, p. 11.
Sources
- Books
- Broschat, Timothy K.; Meerow, Alan W. (1991). Betrock's Reference Guide to Florida Landscape Plants. Cooper City, Florida: Betrock Information Systems. ISBN 978-0-9629761-0-0. OCLC 740077743. Retrieved 19 September 2025.
- Jones, David L. (1998). Cycads of the World. Frenchs Forest, New South Wales: Reed New Holland. ISBN 978-1-876334-09-3. OCLC 39289891.
- Norstog, Knut; Nicholls, Trevor J. (1997). The Biology of the Cycads. Ithaca, New York: Comstock Pub. Associates. ISBN 978-0-8014-3033-6. OCLC 35865546.
- News letters
- Govan, Carol; Kahn, Gail (Spring 2005). "GYMNOSPERMS: The Naked Truth" (PDF). Wellesley College Friends of Horticulture. Retrieved 19 September 2025.
- Web sources
- Hassler, Michael (4 September 2025). "Synonymic Checklist and Distribution of the World Flora. Version 25.09". World Plants. Retrieved 19 September 2025.
- IFAS Extension (2025). "Dioon – Gardening Solutions". IFAS Extension. University of Florida. Retrieved 19 September 2025.
- POWO (2025). "Dioon spinulosum Dyer ex Eichl". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 18 September 2025.
- Vovides, A.P.; Chemnick, J.; Gregory, T. (2022). "Dioon spinulosum". IUCN Red List of Threatened Species. 2022 e.T42149A243387612. doi:10.2305/IUCN.UK.2022-1.RLTS.T42149A243387612.en. Retrieved 19 September 2025.
External links
- Encyclopædia Britannica Giant dioon.
- Michigan State University Horticulture [1].