Caribbean Journal of Science, Vol. 35, No. 3-4, 265-285, 1999 Copyright 1999 College of Arts and Sciences University of Puerto Rico, Mayagüez Annotated Checklist for the Tracheophytes of Rio Abajo Forest Reserve, Puerto Rico PEDRO ACEVEDO-RODRIGUEZ^ AND FRANKLIN S. AXELROD^ ^Department of Botany, National Museum of Natural History, MRC-166, Wasltington, DC 20560. [email protected]. ^Department of Biology, University of Puerto Rico, P.O. Box 23360, Rio Piedras, PR 00931-3360. [email protected] ABSTRACT.•An annotated checklist for the tracheophytes of the Rio Abajo Forest Reserve and adjacent areas has been produced to increase the botanical knowledge and to foster further biological research in this important ecosystem. This paper lists 925 taxa, most of which are based on voucher specimens or on sight records by the authors. The list also contains 111 unconfirmed records obtained from the field books of Roy O. Woodbury (former botany professor at the University of Puerto Rico), for a total of 1036 taxa. Relative frequency and local distribution is discussed for most of the species. Five species (Phenax soneratii, Brachi- aria erucifortnis, Digitaria ekmanii, Ichnanthus conjunctus, and Setaria lutescens) are reported for Puerto Rico for the first time, and the endemic vine Marsdenia elliptica was collected for the first time in 100 years. INTRODUCTION lished in 1935 and the once deforested landscape was slowly transformed through Rio Abajo is the largest biological reserve the establishment of numerous timber (2275 ha) found on limestone substrate in plantations (mostly in the valleys on deep Puerto Rico (DRN, 1976). Within the karst soils) and through the regeneration of natu- region, it is the only reserve with relatively ral vegetation on the surrounding hills. The high elevations (to 300 m), and that con- plantations have turned into mixed forests tains two of the Holdridge life zones (sub- due to the reincorporation of numerous in- tropical wet and subtropical moist life digenous species. The surrounding sub- zones; Ewel & Whitmore, 1973). It is conical, steep-sided hills, locally know as equally important as a reintroduction site mogotes (Monroe, 1980), bear secondary for- for the endangered and endemic Puerto ests with different degrees of development, Rican parrot. Currently, there is a an avi- depending on land use history and edaphic ary-field station managed by the Depart- conditions. Forest communities vary from ment of Natural and Environmental Re- evergreen moist, mixed forests at the base sources with the objective of reintroducing of hills, to scrublands on some dryer hill into the forest this once ubiquitous bird. tops. During the first three decades of this cen- The annotated checklist presented in this tury, due to agriculture and extractive prac- paper is the result of over a decade of re- tices, the Rio Abajo area was intensively search and collecting. In our studies, we deforested (Alvarez et al., in press). Nu- have examined not only our own collec- merous homesteads were established in the tions, but also those of James D. Ackerman, area, and practically every valley was un- Gary Breckon, Luis E. Gregory, Bruce Han- der cultivation, with surrounding hills de- sen, Alain Liogier, Elbert E. Little Jr., forested due to the extraction of wood for George R. Proctor, Rubén Sauleda, and Roy charcoal and building materials. With the O. Woodbury. Names of confirmed records advancement of industrialization, these appear in italics, usually followed by infor- lands were slowly abandoned and re- mation about their frequencies and habitat claimed by natural secondary vegetation. within Rio Abajo, and by a collector name The Rio Abajo Forest Reserve was estab- and collection number (both in parenthe- 265 266 P. ACEVEDO-RODRIGUEZ AND F. S. AXELROD sis). Records lacking collection numbers are fieldbooks) records for a total of 1036 taxa. based on field observations by one or both A total of 878 species (ca. 85%) of these are authors, or are based on Little and Wad- native, of which 88 are endemic. The re- sworth (1964) and Little et al. (1974). In ad- maining 158 taxa are exotics that are either dition, 111 unconfirmed records have been persistent after cultivation or have become obtained from the fieldbooks of Roy O. naturalized in Rio Abajo. The nomencla- Woodbury (former professor at the Univer- ture follows that of Liogier (1985-1997), sity of Puerto Rico). They are included here Acevedo-Rodriguez (1996), King and Rob- to produce a checklist as complete as pos- inson (1987), Bremer (1994), and Ackerman sible, with the understanding that they (1995) for the flowering plants, and Proctor must be confirmed before accepted as de- (1989) for the ferns and fern allies. Families finitive. We only considered species with a are listed in alphabetical order with Pteri- high probability of being found in Rio dophytes followed by the flowering plants. Abajo based on collections from other karst The specimens cited in this work are de- areas in Puerto Rico. These records appear posited in the following herbaria: in brackets and are indicated by an asterisk. During the last decade and a half, at least 1. Department of Natural Resources (SJ): five new species have been described from Acevedo (1-500); Proctor this region {Calyptranthes acevedoi, Calyp- 2. New York Botanical Garden (NY): Acev- tranthes esiremerae, Asplenium corderoanum, edo (501-2693), Thelypteris abdita, and Thelypteris hildae) by 3. Smithsonian Institution (US): Acevedo > either Liogier (1985,1986) or Proctor (1985, 2674. 1989). In addition, several nearly extinct or 4. University of Puerto Rico Botanical Gar- rare endemic species have been discovered den (UPR); Acevedo 501-2693), Gregory, in Rio Abajo by one of the authors, i.e., Cor- Liogier, Little, and Woodbury nutia obovata, IDaphnopsis helleriana, Marsde- 5. University of Puerto Rico, Department nia elliptica, Ottoschulzia rhodoxylon, Pleoden- of Biology, Mayagüez campus (MAPR): dron macranthum, Schoepfia arenaria, and Breckon. Solatium drymophilum. All these species ex- 6. University of Puerto Rico, Department cept M. elliptica have been known to occur of Biology, Rio Piedras campus (UPRRP): in Rio Abajo by the local botanical commu- Axelrod and Ackerman. nity for nearly a decade, and there have 7. University of Southern Florida (USF). been efforts into evaluating their popula- Hansen and Sauleda. tions and reproductive success. The occur- rence of M. elliptica in Rio Abajo constitutes Woodbury's notebooks are deposited at a new finding. This species was known the International Institute of Tropical For- only from Monte Jimenes in the Luquillo estry (IITF). Mountains, where it was last collected by Paul Sintenis (num. 1452) in 1885. As a result of the most recent field work, Acknowledgments.•We would like to three new species of flowering plants, thank Mark T. Strong (US) for reviewing (Trichostigma sp. nov., Pisonia sp. nov. and the manuscript and for identifying some of Ocotea sp. nov.) have been discovered in the Cyperaceae and Monocot collections; this reserve and will be published as ad- Dr. George R. Proctor (SJ) for identifying equate material becomes available. In addi- most of the Pteridophytes; Dr. Paul M. Pe- tion, Phenax soneratii (Urticaceae), and the terson (US) for identifying some of the following four grasses: Brachiaria erucifor- grasses; John F. Pruski (US) for identifying mis, Digitaria ekmanii, Ichnanthus conjunctus, some of the Asteraceae and for proof- and Setaria lutescens were discovered in Rio reading the Asteraceae nomenclature; José Abajo and are here reported for Puerto Rico L. Chabert, Departamento de Recursos for the first time. Naturales y Ambientales (DRNA) for The Rio Abajo Reserve contains 925 con- granting the collecting permits and for firmed and 111 unconfirmed (Woodbury's making the Rio Abajo facilities available for TRACHEOPHYTES OF THE RIO ABAJO RESERVE 267 this study; and Dr. Ariel E. Lugo (IITF) for CHECKLIST providing transportation and logistical PTERIDOPHYTES support in the field. We would also like to thank the curators of the following her- HYMENOPHYLLACEAE baria: SJ, UPR, UPRRP, and US for making Trichomanes angustifmns (Fée) Wessels; very rare (Ax- their collections available for this study. elrod 9400). Trichomanes crispum L.; rare, vicinity of Camp Crozier This project received partial funding from {Proctor 40093). the initiative of the Latin America and the Trichomanes hookeri C. Presl.; rare, vicinity of Camp Caribbean Program of the World Wildlife Crozier {Proctor 40704). Fund. Trichomanes kappierianum Stern; rare, collected once {Axelrod 7952). Trichomanes krausii Hook. & Grev.; occasional to lo- LITERATURE CITED cally common {Axelrod 7811). Trichomanes ¡ineolatum (V.D. Bosch) Hook, rare, adja- Acevedo-Rodriguez, P. 1996. Flora of St. John, U.S. cent to forest limits {Axelrod 7953). Virgin Islands. Mem. New York Bot. Gard. Vol. 78. Trichomanes ovale (Fourn.) W. Boer; rare, vicinity of 581pp. Camp Crozier {Proctor 41183). Ackerman, J. D. 1995. An orchid flora of Puerto Rico [Trichomanes punctatum Poir. ssp. punctatum *] and the Virgin Islands. Mem. New York Bot. Gard. Trichomanes pusillum Sw.; rare, collected once, {Axelrod Vol. 73. 203 pp. 7981). Alvarez Ruiz, M., P. Acevedo-Rodriguez, and M. CYATHEACEAE Vázquez, (in press). Quantitative description of the Cyathea andina (Kart.) Domin; occasional, secondary structure and diversity of the vegetation in the forests {Proctor 41046). limestone forest of Rio Abajo, Arecibo-Utuado, Cyathea arbórea (L.) J.E. Sm.; occasional to common, Puerto Rico. Acta Científica. understory of moist valley forests. Bremer, K. 1994. Asteraceae: Cladistics & classifica- Cyathea hórrida (L.) J.E. Sm.; occasional, understory of tion. Timber Press. Portland, Oregon. 752 pp. moist valley forests {Acevedo 10682). Departamento de Recursos Naturales de Puerto Rico, Cyathea portoricensis Spreng, ex Kuhn; endemic, occa- 1976. The master plan for the Commonwealth for- sional, moist disturbed trailsides {Acevedo 10683). est of Puerto Rico. San Juan, Puerto Rico. Cyathea pungens (Willd.) Domin; occasional, vicinity of Ewel, J. J. and J. L. Whitmore. 1973. The ecological life Camp Crozier {Proctor 40707).