Adiantum vivesii
Encyclopedia
Adiantum vivesii is a rare species
of fern
known by the common name Puerto Rico maidenhair. It is in the maidenhair fern
genus Adiantum.
, where it is known from a single population made up of perhaps 1000 individuals near Quebradillas
, in the San Juan – Caguas – Guaynabo metropolitan area on the northern side of the island. The fern was discovered in 1985 and described to science as a new species in 1989. Soon after, it was listed as an endangered species
.
published a master's thesis
detailing her studies of the rare fern. She had carefully dug around most of the single population and discovered it was actually one individual connected by a long rhizome
. The fern produces spore
s but no gametophyte
s and there were no new, small individuals in the vicinity; the student concluded that the fern does not undergo sexual reproduction
, only vegetative reproduction
, sprouting up from its extensive rhizome.
Evidence supports the conclusion that the fern is one plant that is a sterile hybrid of two common fern species, and as it does not reproduce but only increases in size by resprouting, it is not a valid species
in its own right. Therefore, the United States Fish and Wildlife Service
recommends it be removed from the endangered species list
. As of 2011 it is still on the list.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of fern
Fern
A fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...
known by the common name Puerto Rico maidenhair. It is in the maidenhair fern
Maidenhair fern
Adiantum , the maidenhair ferns, is a genus of about 200 species of ferns in the family Pteridaceae, though some researchers place it in its own family, Adiantaceae...
genus Adiantum.
Distribution
Adiantum vivesii is endemic to Puerto RicoPuerto Rico
Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...
, where it is known from a single population made up of perhaps 1000 individuals near Quebradillas
Quebradillas, Puerto Rico
Quebradillas is a municipality of the island of Puerto Rico, located in the north-western shore bordering the Atlantic Ocean, north of San Sebastián; east of Isabela; and west of Camuy. Quebradillas is spread over swven wards and Quebradillas Pueblo...
, in the San Juan – Caguas – Guaynabo metropolitan area on the northern side of the island. The fern was discovered in 1985 and described to science as a new species in 1989. Soon after, it was listed as an endangered species
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
.
Single population — sterile hybrid
In 2000, a student at the University of Puerto RicoUniversity of Puerto Rico
The University of Puerto Rico is the state university system of Puerto Rico. The system consists of 11 campuses and has approximately 64,511 students and 5,300 faculty members...
published a master's thesis
Thesis
A dissertation or thesis is a document submitted in support of candidature for an academic degree or professional qualification presenting the author's research and findings...
detailing her studies of the rare fern. She had carefully dug around most of the single population and discovered it was actually one individual connected by a long rhizome
Rhizome
In botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...
. The fern produces spore
Spore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...
s but no gametophyte
Gametophyte
A gametophyte is the haploid, multicellular phase of plants and algae that undergo alternation of generations, with each of its cells containing only a single set of chromosomes....
s and there were no new, small individuals in the vicinity; the student concluded that the fern does not undergo sexual reproduction
Sexual reproduction
Sexual reproduction is the creation of a new organism by combining the genetic material of two organisms. There are two main processes during sexual reproduction; they are: meiosis, involving the halving of the number of chromosomes; and fertilization, involving the fusion of two gametes and the...
, only vegetative reproduction
Vegetative reproduction
Vegetative reproduction is a form of asexual reproduction in plants. It is a process by which new individuals arise without production of seeds or spores...
, sprouting up from its extensive rhizome.
Evidence supports the conclusion that the fern is one plant that is a sterile hybrid of two common fern species, and as it does not reproduce but only increases in size by resprouting, it is not a valid species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
in its own right. Therefore, the United States Fish and Wildlife Service
United States Fish and Wildlife Service
The United States Fish and Wildlife Service is a federal government agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats...
recommends it be removed from the endangered species list
Endangered Species Act
The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and...
. As of 2011 it is still on the list.