Cyathea crassa is a species of tree fern

Cyatheales

The order Cyatheales is a taxonomic division of the fern subclass, Cyatheatae, which includes the tree ferns. No clear morphological features characterize all of the Cyatheales, but DNA sequence data indicates that the order is monophyletic. Some species in the Cyatheales have tree-like growth...

 endemic

Endemic (ecology)

Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the...

 to the Santo Domingo

Santo Domingo

Santo Domingo, known officially as Santo Domingo de Guzmán, is the capital and largest city in the Dominican Republic. Its metropolitan population was 2,084,852 in 2003, and estimated at 3,294,385 in 2010. The city is located on the Caribbean Sea, at the mouth of the Ozama River...

 area in the Dominican Republic

Dominican Republic

The Dominican Republic is a nation on the island of La Hispaniola, part of the Greater Antilles archipelago in the Caribbean region. The western third of the island is occupied by the nation of Haiti, making Hispaniola one of two Caribbean islands that are shared by two countries...

. Little is known about this rare tree fern.

C. crassa is part of the Cyathea woodwardioides complex from the Greater Antilles

Greater Antilles

The Greater Antilles are one of three island groups in the Caribbean. Comprising Cuba, Jamaica, Hispaniola , and Puerto Rico, the Greater Antilles constitute almost 90% of the land mass of the entire West Indies.-Greater Antilles in context :The islands of the Caribbean Sea, collectively known as...

 together with five other species: Cyathea fulgens

Cyathea fulgens

Cyathea fulgens is a species of tree fern native to Cuba, Jamaica and Hispaniola. It forms part of the complex centered around Cyathea woodwardioides comprising six very similar taxa from the Greater Antilles. The other five species are Cyathea crassa, Cyathea grevilleana, Cyathea portoricensis and...

, Cyathea grevilleana

Cyathea grevilleana

Cyathea grevilleana is a species of tree fern endemic to Jamaica, where it grows in moist gullies and on wooded hills in both calcareous and noncalcareous soils at an altitude of 200-1200 m. The trunk of this plant is erect, about 7 m tall, and 10-15 cm in diameter. It is characteristically clothed...

, Cyathea portoricensis, and Cyathea tussacii.

This species is not conspecific with Alsophila crassa (Karsten, 1869), which is based on material collected from wet, cold, montane forest at Mérida

Mérida, Mérida

Santiago de los Caballeros de Mérida, Venezuela, is the capital of the municipality of Libertador and the state of Mérida, and is one of the principal cities of the Venezuelan Andes...

 by Franz Engel in 1859. There are no modern collections that match Karsten's description and so the identity of this species remains unclear.

The naming of C. crassa represents some taxonomic

Taxonomy

Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...

 problems. If the genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Alsophila is recognised, the specific epithet

Epithet

An epithet or byname is a descriptive term accompanying or occurring in place of a name and having entered common usage. It has various shades of meaning when applied to seemingly real or fictitious people, divinities, objects, and binomial nomenclature. It is also a descriptive title...

 crassa is unavailable for this tree fern, having been used by Karsten. To avoid confusion, David Conant renamed it Alsophila jimeneziana in 1983.