Adiantum vivesii

No Common Name

Description

Adiantum vivesii (maidenhair) is a gregarious colonial fern with creeping nodose and rhizomes about 0.1 in (2.5-3.0 mm) thick. The fronds are distichous (in two vertical rows) and erect-spreading, approximately 0.2 in (0.5 cm) apart and 18-28 in (45-71 cm) long. The stipes or stalks are lustrous purple-black, 10-18 in (25-46 cm) long, irregularly branched, and have hairlike scales. The frond's blades are broad and irregular, 8-11 in (20-28 cm) long, and 9-14 in (23-35 cm) broad. The rachises and costae are more densely covered with hairlike scales than the stipes. The blades have two or three alternative or sometimes subopposite pinnae, the terminal one being larger. These are lance-oblong, 5-8 in (13-20 cm) long, and 1.4-2 in (3.5-5 cm) broad.

The terminal pinna may be up to 2.8 in (7 cm) broad, stalked, and is often somewhat inequilateral. Each pinna has 10-13 pairs of alternate, narrowly oblong-falcate pinnules, which are unequally cuneate at the base. The outer sterile margins of the pinna are irregularly serrulate and the tissue is dull green on both sides. Five elliptic to linear sori (re-productive bodies) are borne along the basal half of the acroscopic margin, and they are close or contiguous but distinct. The indusioid is gray-brown and turgid, with an erose margin.

Habitat

This species occurs in a deeply shaded hollow at the base of north-facing limestone cliffs at a lower to middle elevation of approximately 820 ft (250 m).

Distribution

A. vivesii species is only known from a single colony of an estimated 1,000 plants, or growing apices, at Barrio San Antonio in the municipality of Quebradillas, Puerto Rico.

Threats

A. vivesii occurs on privately owned land and is known from only a single locality. Clearing or development of this area would result in elimination of the species. Also, this species could be an attractive item for collectors.

Conservation and Recovery

Because A. vivesii occurs on privately owned land and is known from only a single locality, clearing or development of this area would result in the elimination of the only known population.

Research is needed to determine this species' life history and ecological requirements and to develop and refine propagation and transplant techniques. Surveys are needed to determine if other populations exist and to locate potential transplant sites.

Contacts

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
1875 Century Blvd., Suite 200
Atlanta, Georgia 30345
(404) 679-4000
http://southeast.fws.gov/

Boquerón Ecological Services Field Office
Boquerón, Puerto Rico 00622-0491
Telephone: (787) 851-7297
Fax: (787) 851-7440

References

Mickel, J. T. 1979. How to Know the Ferns and Fern Allies. William C. Brown Publishing, Dubuque, Iowa.

U. S. Fish and Wildlife Service. 9 June 1993. "Endangered and Threatened Wildlife and Plants: Determination of Endangered Status for Four Endemic Puerto Rican Ferns." Federal Register 58 (109): 32308-32311.