Dioon is a plant
genusIn biology, a genus is a taxonomic unit used in the classification of living and fossil organisms. The term comes from Latin genus "descent, family, type, gender" , cognate with – genos, "race, stock, kin" ..In addition, genus is a taxonomic rank in the hierarchy In biology, a genus (plural:...
of 14 described
speciesIn biology, a species is:* a taxonomic rank or* a unit at that rank ....
. They are
cycadCycads are a group of seed plants characterized by a large crown of compound leaves and a stout trunk. They are evergreen, gymnospermous, dioecious plants having large pinnately compound leaves...
s in the family
ZamiaceaeThe Zamiaceae are a family of cycads that are superficially palm or fern-like. They are divided into two subfamilies with eight genera and about 150 species in the tropical and warm temperate regions of Africa, Australia and North and South America....
, and native to
MexicoThe United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
,
HondurasHonduras is a republic in Central America. It was formerly known as Spanish Honduras to differentiate it from British Honduras...
, and
NicaraguaNicaragua officially the Republic of Nicaragua , is a representative democratic republic. It is the largest country in Central America with an area of 130,373 km
2. The country is bordered by Honduras to the north and Costa Rica to the south. The Pacific Ocean lies to the west of...
. Their habitats include tropical forests, pine-oak forest, and dry hillsides, canyons and coastal dunes. In North America, the Dioon can be seen growing from southern Florida up to Savannah,Georgia.
Dioons are
dioeciousDioecious species are whose members can produce only one type of gamete; each individual organism belonging to a dioecious species is distinctly male or female . The majority of animal species are dioecious...
, palmlike shrubs with cylindrical stems, usually with many leaves. Leaf bases are persistent or shedding to leave smooth bark.
Dioon is a plant
genusIn biology, a genus is a taxonomic unit used in the classification of living and fossil organisms. The term comes from Latin genus "descent, family, type, gender" , cognate with – genos, "race, stock, kin" ..In addition, genus is a taxonomic rank in the hierarchy In biology, a genus (plural:...
of 14 described
speciesIn biology, a species is:* a taxonomic rank or* a unit at that rank ....
. They are
cycadCycads are a group of seed plants characterized by a large crown of compound leaves and a stout trunk. They are evergreen, gymnospermous, dioecious plants having large pinnately compound leaves...
s in the family
ZamiaceaeThe Zamiaceae are a family of cycads that are superficially palm or fern-like. They are divided into two subfamilies with eight genera and about 150 species in the tropical and warm temperate regions of Africa, Australia and North and South America....
, and native to
MexicoThe United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
,
HondurasHonduras is a republic in Central America. It was formerly known as Spanish Honduras to differentiate it from British Honduras...
, and
NicaraguaNicaragua officially the Republic of Nicaragua , is a representative democratic republic. It is the largest country in Central America with an area of 130,373 km
2. The country is bordered by Honduras to the north and Costa Rica to the south. The Pacific Ocean lies to the west of...
. Their habitats include tropical forests, pine-oak forest, and dry hillsides, canyons and coastal dunes. In North America, the Dioon can be seen growing from southern Florida up to Savannah,Georgia.
Dioons are
dioeciousDioecious species are whose members can produce only one type of gamete; each individual organism belonging to a dioecious species is distinctly male or female . The majority of animal species are dioecious...
, palmlike shrubs with cylindrical stems, usually with many leaves. Leaf bases are persistent or shedding to leave smooth bark. The genus is commonly divided into two groups of distinct morphology. The first includes
D. mejiae,
D. rzedowskii, and
D. spinulosum, "characterized generally by large fronds, well-developed trunks, and massive cones". The second group contains
D. califanoi,
D. caputoi,
D. edule,
D. holmgrenii,
D. merolae,
D. purpusii,
D. sonorense, and
D. tomasellii, which are "less robust, with generally shorter trunks, considerably shorter fronds, and smaller cones" (Norstog & Nichols 1997).
The
leavesIn botany, a leaf is an above-ground plant organ specialized for photosynthesis. For this purpose, a leaf is typically flat and thin. There is continued debate about whether the flatness of leaves evolved to expose the chloroplasts to more light or to increase the absorption of carbon dioxide. In...
are pinnate, spirally arranged, interspersed with cataphylls, with leaflets not articulated and lacking a midrib. The lower leaflets are often reduced to spines. The
sporophyllA sporophyll is a leaf that bears sporangia. Both microphylls and megaphylls can be sporophylls. In heterosporous plants, sporophylls bear either megasporangia , or microsporangia...
s are not in vertical rows in cones, and the megasporophyll apices are broadly flattened, upturned, and overlapping.
Species
- Dioon angustifolium
- Dioon argenteum
- Dioon califanoi
- Dioon caputoi
- Dioon edule
Dioon edule is a cycad native to Mexico, also known as palma de la Virgen.Two subspecies are known*Dioon edule subsp. angustifolium*Dioon edule subsp. edule- Dioon Edule var. Edule :...
- Dioon holmgrenii
- Dioon mejiae
Dioon mejiae is a cycad native to Honduras and Nicaragua. It is also known as palma teosinte, teocinte, teocinta , teocintle, teocsinte, teosinte, tiusinte, tusinte. All are translated to mean "sacred ear."...
- Dioon merolae
- Dioon purpusii
- Dioon rzedowskii
- Dioon sonorense
- Dioon spinulosum
Dioon spinulosum, giant dioon, or gum palm, 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 12m in height. The tree is found at low elevations to 300 m above sea...
- Dioon stevensonii
- Dioon tomasellii