A RECONSIDERATION OF SPONDIAS MOMBIN L. (ANACARDIACEAE) THOMAS B. CROAT2 ABSTRACT Spondias radlkoferi J. Donn. Sm. is considered distinct from Spondias mombin L. Itdiffers chielfy in flowering precociously about one month later than S. mombin, in havingfewer styles and a fruit which is green at maturity with an oblong endocarp, in having a trunkwith a smooth periderm, and in forming droplets of viscid, cloudy sap when slashed. It ismost easily recognized by the villous pubescence of its parts. The genus Spondias as treated by Blackwell (1967: 363-367) in the Floraof Panama consists of two species, S. purpurea L. and S. mombin L. Field workdone on Barro Colorado Island indicates that another taxon, S. radlkoferi J.Donn. Sm., must be segregated from S. mombin L. The occurrence of the segregate taxon was first brought to my attentionby Dr. Dennis Knight (University of Wyoming). After he sampled a numberof Spondias by slashing the trunks, he concluded that two taxa were involvedsince part of the trees sampled produced small droplets of viscid, cloudysap shortly after having been slashed, while others did not. He believed theplants to be otherwise quite similar. Robin Foster (Duke University), inthe course of his phenological studies on Barro Colorado Island, noted otherfeatures which separate Spondias into two species. He noted that one groupof trees flowers about one month later than do others and that the latter groupdevelop fruits which are elongate and green at maturity. The other Spondiastrees produce fruits which are more globose and turn yellow, then orange atmaturity. It was not surprising to discover that at least some native Panamanianswere already familiar with part of these differences and had called the green-fruited Spondias "jobo verde." Mr. James Zetek wrote, in a recently discoveredletter at the Field Museum, to Paul Standley on May 6, 1936 from Barro ColoradoIsland: "Here we have a mombin that resembles the yellow mombin, but itnever gets yellow, it stays green ail the time." He also added, "The trunk ofthe green one is smooth compared to that of the yellow." Recent studies have confirmed the observations of Zetek, Knight, and Foster.Other characters have also been found which further delimit Spondias mombinL. and S. radlkoferi J. Donn. Sm. Spondias radlkoferi is readily distinguished from S. mombin both in thefield and in the herbarium. The former usually flowers about a month laterthan S. mombin, though sufficient overlap occurs in their flowering periodsto allow hybridization. Plants of both species may be common in mixed popu-lations on Barro Colorado Islands. However, while they are without question 'Partial support from National Science Foundation Grant GB-34502 is acknowledgedwith thanks. SMissouri Botanical Garden, 2315 Tower Grove Avenue, St. Louis, Missouri 63110. ANN. MISSOURI BOT. GARU. 61: 483-490. 1974.