Flora of Barro Colorado Island

History of Botanical Studies


Panama and the Canal Zone. The earliest botanical collections in Panama were made about 1700 by James Wallace, who was associated with the old Scottish settlement of New Caledonia, and though they are still extant in London they have not been carefully studied to this day. Serious botanical activity began in Panama about 1825, when J. E. Billberg collected near Portobelo in Colón Province. Other nineteenth-century collectors include B. C. Seemann (1846-49), P. D. Duchassaing (1849-51), A. Fendler (1850), K. Halsted (1850), and Sutton Hayes (1860-63). Early twentieth-century collectors of note in Panama were R. S. Williams (1908), C. W. Powell (1907-27), H. F. Pittier (1911, 1914-15), W. R. Maxon (1911, 1923), E. P. Killip (1917-18, 1922), C. V. Piper (1923), P. C. Standley (1923-25), G. P. Cooper (1927-28), A. M. Chickering (1928), Brother Paul (1934), M. E. Spence Davidson (later Mrs. R. A. Terry; 1938, mainly from Chiriqui), and M. E. Terry and R. A. Terry from Darien (late 1930's).

Until 1930 the collectors who came to Panama visited only a relatively small portion of the country and, with the notable exception of Henri Pittier, most collected in a relatively restricted area, many of them never leaving the region of the isthmus.

Botanical activity leading to a Flora of Panama began in 1934 with the efforts of R. E. Woodson, Jr., and his associates from the Missouri Botanical Garden. Among those who participated in these efforts in the 1930's were R. W. Schery, R. J. Seibert, J. A. Steyermark, P. C. Allen, A. A. Hunter, and Carol Dodge. Particularly notable was Paul C. Allen, who collected more widely in Panama than anyone up to that time. About 10,000 numbers were collected during this prewar era; as a result of this activity, Woodson and Schery initiated the Flora of Panama project in 1943. Subsequent collecting in Panama by staff and students of the Missouri Botanical Garden has yielded an estimated 73,000 collections.

During World War II, San Jose Island in the Bay of Panama was intensively collected by I. M. Johnston, C. O. Erlanson, and others, resulting in publication of a flora, and in 1940-41 H. von Wedel collected extensively in Bocas del Toro. Little other collecting was done in Panama during or after World War II.

Financial support for the Flora of Panama project was obtained from the National Science Foundation beginning in 1957 and continues through to the completion of the project, which is expected in 1978. Field work in Panama by the Missouri Botanical Garden was renewed in 1959 by John D. Dwyer, working with Kenton Chambers, William Stern, and John Ebinger (all associated with Yale University). Working independently, Dwyer made three additional expeditions to Panama between 1961 and 1964.

Full-scale reactivation of the field program in Panama began in 1966, under the direction of Walter H. Lewis, with increased financial assistance from the National Science Foundation. Four expeditions were made to Panama under Lewis's direction between 1966 and 1969, accumulating 5,581 collections. Participating in these expeditions were staff and students including John Dwyer, André Robyns, Derek Burch, Tom Croat (principal investigator 1972-77), Marshall Crosby, Duncan Porter (principal investigator 1971-72), Tom Elias, D. F. Austin, Royce L. Oliver, Kenneth R. Robertson, Will H. Blackwell, Jr., Joan W. Nowicke, Bruce MacBryde, John E. Ridgeway, L. H. Durkee, John L. Hawker, Susan E. Verhoek-Williams, Jerry R. Castillon, and Richard K. Baker.

A field station and herbarium were established in Panama in 1969 by the Missouri Botanical Garden and the Panama Canal Company, through the efforts of Walter Lewis, then director of the herbarium at Missouri, and A. I. Baumann, then supervisor of the Community Services Division of the Panama Canal Company. The facility was named Summit Herbarium (SCZ), and it has received support from the National Science Foundation. Others important in the initial organization of the station were Edwin L. Tyson, then with Florida State University in the Canal Zone, and Roy Sharp, then supervisor of Grounds and Maintenance for the Panama Canal Company. The initial collection of approximately 6,000 mounted sheets was made by Tyson and others under the auspices of the Army Tropic Test Center in the Canal Zone. The field station, with a residence for the curator and a field vehicle, has enabled Missouri to maintain successive collectors in Panama since that time: Tom Croat (1971), Al Gentry (1972), Helen Kennedy (1973), Michael Nee (1974), Scott Mori (1975), and James Folsom (1977), with a repeat by Tom Croat during 1976. Since the establishment of Summit Herbarium, Missouri has made 50,000 collections in Panama.

The herbarium and drying facilities of Summit Herbarium, now located at Ancon in the Canal Zone, are sponsored jointly by the Smithsonian Tropical Research Institute (STRI) and the Missouri Botanical Garden. The drying facilities, now housed in the STRI Tivoli Building, feature about 8,500 watts of electric dryers in a fire-proof room and are adequate for a sustained collecting program.

In addition to resident collectors employed by the Flora of Panama project, Missouri Botanical Garden has sponsored other expeditions to Panama. In 1972, the National Geographic Society helped sponsor a phytogeographic survey of the Burica Peninsula by Tom Croat. With the assistance of Ron Liesner and Philip Busey, 3,600 collections were made. In 1975, Al Gentry, with support from the National Geographic Society and assistance from Scott Mori, made an expedition to Cerro Tacarcuna on the Colombian border, netting 1,100 collections.

John Dwyer, both independently and with his students, has made about 6,000 collections in Panama on several expeditions since 1964. Among Dwyer's students who have collected in Panama are Joseph Kirkbride, Victoria Hayden, T. S. Elias, B. R. Lallathin, David Spellman, and Richard Wunderlin. Joseph Kirkbride, with James A. Duke, collected about 1,000 numbers in Panama. The most important of these are from an overland expedition from Bocas del Toro on the Caribbean to Chiriqui.

Numerous expeditions to Panama have been made by Tom Croat since 1967 on the Flora of Barro Colorado Island project (also partially NSF funded). Since 1969 the Flora of Panama project has funded collecting trips by Walter Lewis, John Dwyer, Duncan Porter, W. G. D'Arcy, and Tom Croat. With support from the Flora of Panama project, and with separate NSF funding, W. G. D'Arcy made about 4,000 collections during five visits to Panama.

Other institutions that have been active in Panama include the University of Panama, Duke University, and Florida State University. The University of Panama, principally through the efforts of Mireya D. Correa A. and N. Escobar and their students, has made a significant number of collections in Panama. Robert L. Wilbur, of Duke University, has made eight expeditions to Panama. Students of Wilbur's who have participated in these expeditions include F. Almeda, J. Terri, P. Armond, J. Luteyn, J. Utley, and R. Weaver. Robin Foster, an ecologist trained at Duke, has made numerous collections on Barro Colorado Island and elsewhere in Panama.

Florida State University, through the efforts of R. K. Godfrey, E. L. Tyson, H. Loftin, Sidney McDaniel, K. Blum, and R. L. Lazor, has also made numerous collections in Panama. Particularly noteworthy are the collections of E. L. Tyson between the years 1962 and 1972. During part of this time he was employed by the Army Tropic Test Center, where he established the collection of approximately 6,000 specimens now incorporated with Summit Herbarium. Noteworthy also are L. R. Holdridge and E. A. Lao, who made collections associated with forestry investigations in Panama during the 1960's, and A. Weston, who made recent collections at high elevations in western Panama.

Most noteworthy among botanists not associated with the above-mentioned institutions are Robert L. Dressler of STRI and Jim Duke. Dressler's wide-ranging and selective collecting has yielded numerous interesting and new species. Duke is best known for his collections from Darién, which were made while he was employed by Battelle Memorial Institute as part of a program investigating a new sea-level canal route.

Barro Colorado Island. Probably the first significant plant collecting on the island was that done by Paul Carpenter Standley, who in the course of 8 days (January 17, 1924, and a week in November 1925) made 800 collections. It was principally on the basis of these collections that Standley (1927) published his first checklist for the island. During the summer of 1927, Leslie A. Kenoyer, of Western State Teachers College in Kalamazoo, Michigan, conducted extensive ecological studies on the island. In the course of his work he made 690 collections, and on the basis of these collections, Kenoyer and Standley published in 1929 the first supplement to the Flora of Barro Colorado Island. A second supplement was published by Standley in 1930.

Because of the increase in botanical work on the island during 1931 and 1932, so many collections were accumulated that Standley decided to completely revise the flora. The revision was published in 1933. Collections made during 1931 and 1932 were principally by C. L. Wilson, L. H. and E. Z. Bailey, D. E. Starry, Silvestre Aviles (a local assistant to Bailey), Otis Shattuck, R. H. Wetmore and E. C. Abbe, and R. H. Woodworth and P. A. Vestal. A few collections were also made by C. Ray Carpenter during his studies of monkeys. James Zetek, who together with Thomas Barbour was principally responsible for the establishment of Barro Colorado Island as a preserve, was also the first resident manager. He collected fewer plants than most collectors of his time but his collections are among the most selective. Though Zetek was not a botanist by profession, his correspondence with Standley indicates that he had a keen botanical awareness.

The following list gives the names of all collectors known to have worked on Barro Colorado Island, and when known the number and date of collections:

Abbe, E. C. (see Wetmore and Abbe)

Aviles, S. (few, 1931; see note following list)

Bailey, L. H., and E. Z. Bailey (700, 1931)

Bangham, W. N. (many, late 1920's)

Bartlett, H. H., and T. Lasser (few, 1940)

Brown, W. L. (few)

Busey, P. (few, 1973)

Carleton, M. A. (few)

Carpenter, C. R. (few, 1931-33)

Chardon, C. E. (few)

Chickering, A. M. (few, 1928)

Cook, O. F. (few, early 1920's)

Croat, T. B. (6,614, 1967-75)

D'Arcy, W. G. (few, 1970)

Dare, R. (few, 1972)

Dodge, C. W. (few, 1925)

Dressler, R. L. (few, early 1960's)

Duke, J. A. (few, early 1960's)

Dwyer, J. D. (few, 1961)

Dwyer, Correa, and Pasco (81, 1968)

Ebinger, J. (few, 1960)

Fairchild, G. B. (few, early 1940's)

Faull, J. H. (few)

Folsom, J. (few, 1977)

Foster, R. (1,000, 1969-77)

Garwood, N. (few, 1976-77)

Gentry, A. (few, 1969 and 1971)

Graham, S. (few)

Hayden, M. V. (few, 1965)

Hladik, A. (544, 1967)

Hood, J. D. (few, early 1930's)

Hunnewell, F. W. (few)

Kennedy, H. (few, 1970-72)

Kenoyer, L. A. (680, 1927)

Killip, E. P. (few, 1948)

Knight, D. H. (numerous sterile collections, 1967-68)

Luteyn, J. (few, 1968)

Maxon, W. R. (few, 1923)

McDaniel, S. (few, 1964 and 1972)

Montgomery, G. (300, 1973)

Munch, S. (few, 1973)

Netting, M. G. (few, early 1920's)

Nolla, J. (few)

Oppenheimer, J. (few, 1967-68)

Robyns, A. (few, 1965)

Salvoza, F. M. (few, late 1920's)

Shattuck, O. E. (870, 1930-34)

Standley, P. C. (800, 1924-25)

Starry, D. E. (328, 1931)

Steiner, K. (few, 1976)

Stevens, F. L. (few, 1924)

Stimpson, W. (few, 1967)

Stoutamire, W. P. (few, 1956)

Svenson, H. K. (few)

Terry, M. E., and R. A. Terry (few, late 1930's)

Tyson, E. (few, 1966)

Van Tyne, J. (few, late 1920's)

Weaver, R., and R. Foster (few, 1968)

Wetmore, R. H., and E. C. Abbe (225, 1931-32)

Wetmore, R. H., and R. H. Woodworth (many, late 1920's and early 1930's)

White, P. (few, late 1930)

Wilbur, R. L. (few, 1967)

Wilson, C. L. (158, 1931)

Woodworth, R. H., and P. A. Vestal (450, 1932)

Zetek, J. (few., 1930-43)

Aviles used Shattuck's labels on many of his collections. This has resulted in considerable confusion; the plants collected by Aviles are often cited as Shattuck's collections.

More recent botanical work on the island has been ecologically oriented. Among the projects carried out in the past 10 years are work on bee pollination of orchid flowers, by Robert L. Dressler; on phytosociology, by Dennis H. Knight; on nutrient recycling, by I. N. Healey; and on reproductive potential, by Robin Foster. (Foster was also important as a plant collector, making approximately 1,000 collections on the island.) Zoological work in recent years has dealt principally with studies of animal behavior.

Background of work on the present flora. Standley's final Flora of Barro Colorado Island, published in 1933, gives names and brief descriptions of 1,058 species of vascular plants (as well as 201 nonvascular plants). Relatively little collecting was done on the island between the appearance of Standley's Flora and the beginning of this work. BCI was even at that time the best-collected and presumably the best-known botanically of any tropical area in the New World. No fewer than 5,000 collections had already been made from an area of about 15.6 km2 (6 square miles). Being somewhat of a tropical novice when I began the work, I envisioned a two- or three-year project. I was even told that the flora was so well known that the idea of revising the Flora was ill conceived. Knowing what I now know about the richness of lowland tropical rain forests and the very low frequency of many widespread species, I might have argued that such a flora could never be completed.

The project has taken 10 years to complete. My work began at the Missouri Botanical Garden in August 1967, with a two-week trip to the island in December of that year and successive collecting trips in April and May 1968, in September and October 1968, and from January to March 1969. In March 1970, I moved to the Canal Zone to serve as the first curator of Summit Herbarium, and continued my study of the flora of BCI for 18 months. This long, uninterrupted period of study during 1970 and 1971 provided the opportunity to make many of the phenological observations I feel are so important to this work. Many of the descriptions were also written while I was in the field. This is especially important for palms, certain Araceae, and some other plants that cannot, whether because of their ephemeral nature or their size, be easily described from herbarium material or even from fresh specimens carried back to the laboratory on the island or to Summit Garden. In some cases, BCI species that occur elsewhere in the Canal Zone (especially near Summit Garden, where I was living) were collected and used for descriptions. When I left the Canal Zone in 1971, approximately 60% of the species were described, nearly all of them from living material. Some of the species that are the least detrimentally affected by pressing and drying, e.g., grasses and ferns, were left to be described from herbarium material.

The value of describing plants from living material is that many aspects of the flower or fruit that may be lacking in a dried specimen can be recorded- such features as the disposition of the parts before, during, and after anthesis, and the size and shape of the parts before drying. This approach is especially valuable for mature fruits, since collections of them are rarely found in herbaria.

Methods of field work. Barro Colorado Island has been described by many botanists as a difficult place to collect plants. Insects and other pests, such as ticks, are abundant on the island-perhaps because of the abundance of larger animals, which help to sustain the blood-sucking creatures. Other animals, including snakes, are usually no problem, although I was viciously attacked by a collared peccary one morning on the way to the dining hall from my cabin.

The trails, though generally laid out along ridges and thus offering the easiest ascent to the center of the island, are nonetheless often steep and can be hazardous, especially in the rainy season. Since the island is a preserve and no felling of trees is permitted, collecting within the forest is very difficult. Along the trails the forest is more open, but the light is relatively poor. Even with the aid of binoculars it is difficult to determine which plant, of the several overhead, is the one dropping its flowers or fruits. Sometimes, all that can be done is to find the densest area of fallen parts and then, on the basis of the characteristics of the species, choose the tree that appears most suspect. Often, of course, the plant is a liana or hemiepiphyte, generally not visible from subcanopy levels.

To get into the canopy to collect plants I generally used climbing irons (Croat, 1969). In addition, I carried a sheath knife, a machete, a 50-foot cotton rope with a lead weight, binoculars, and often camera equipment. The technique of climbing with climbing irons, once mastered, is not dangerous. I suffered only one serious fall during the BCI work, and that when I too zealously avoided a swarm of wasps. Ants, especially the large stinging Paraponera, are sometimes hazardous to climbing, but the smaller biting ants that may cover your arms until they are black are always more of a nuisance. Ants are encountered in nearly every tree, especially the flowering trees.

Climbing the wrong tree is a common problem, but switching to another tree from the canopy is usually relatively easy. The most difficult trees to climb are those that have very slender trunks, and thus offer little lateral stability, and those whose girth is so great that the safety rope will not encircle them. Even these can generally be climbed, however, since the stout lianas or hemiepiphytes that press along the trunk of most large trees can be used for support. Trees with very hard bark or wood are also dangerous, since they cannot be penetrated deeply enough to ensure that the gaffs will not slip out. Trunks covered with lianas or epiphytes can be difficult to climb, as well. It is often necessary in these cases to remove the safety rope to get through the tangle-a safe enough proposition, since it would be difficult to fall out of these tangles even if you wanted to. At times I became so entangled I regretted that I could not fall out!

By contrast, collecting along the shore is relatively easy. Because BCI has so recently come to be an island, the shoreline does not support the exclusively riparian vegetation found in a natural situation. Consequently, some species not normally found along water's edge can still be collected along the shore of the island. Perhaps more important, many shoreline trees represent regrowth of trees that have fallen into the lake, and branching may occur near the ground and over the lake, allowing for easy collecting of many of the same species that in the forest would demand an energetic climb. Lianas are exceedingly difficult to collect in the forest, even from the canopy, because they tend to grow only across the surface of the canopy, and are difficult to reach without venturing far out on a limb. However, along the shore, many liana species come down almost to the water and can be collected easily.

Collecting from a boat can be troublesome, because anything accidentally dropped over the edge may disappear into as much as 20 feet of murky water, even very near the shore. Two cameras, a pair of eyeglasses, binoculars, and a host of other miscellaneous things met their end in this manner during my work on this project. The advantages of the shore -easy access and a multiplicity of species - are somewhat offset by other inconveniences. A boat seldom offers a very stable platform on which to work, especially if the water is choppy, and the larger waves created by passing ships can be even more vexing. On one collecting trip, my boat was struck from the stern by a large wave and immediately sank. Fortunately, I was near the shore. Running onto barely submerged tree stumps is another hazard of shoreline collecting. Still another is the many wasps' nests that hang low over the water; often, I did not spot these until I was hopelessly mired in Hydrilla and unable to beat a quick retreat.

The most poorly collected part of the shore lies between the end of Armour Trail and the western tip of Peña Blanca Point. The waters here are choked with tree trunks, and navigation is difficult. The forest that adjoins this area on the western side of the island -the farthest point from the Laboratory Clearing and the boat dock is also poorly collected, and the area can be counted upon for more species new to the flora.