JOURNAL OF THE ARNOLD ARBORETUM SCIIZ)(OC AR)IA BELIZENSIS: A SPECIES OF PURDIAEA (CYRILLACEAE: FROM CENTRAI AMERICA JOAB L. THOMAS ABOUT THIRTY YEARS AGO specimens of an unusual and very distinctivetree were collected in British Honduras by William A. Schipp and sent tothe Field Museum of Natural History. It soon became evident that thistree was unknown in the Central American flora, and the specimens wereeventually distributed under a provisional name as a new genus and spe-cies, Schizocardia belizensis, without any indication of relationship. Later,Smith and Standley (1932) described the plant under this name as repre-senting a second genus in the Clethraceae, a relationship suggested by thecollector. Recently, Dr. C. E. Wood suggested that I look at specimens of Schizo-cardia. indicating that the plant resembled members of the Cyrillaceae.Examination of these specimens revealed that this plant fits well within thelogical generic limits of Purdiaea, in the Cyrillaceae. and that it should betransferred to that genus.Purdiaea belizensis (Smith & Standley) Thomas, comb. nov. Schizocardia belizensis Smith & Standley. Trop. Woods 32: 9. 1932. I)rTRIBuTION. British Honduras. Dist. Stann Creek: Nineteen Mile. StannCreek Valley. . 1t. . Schipp 905 (type. F; isotypes. A, ;H): near Middlesexi'. .1. Schipp 443 (A. F): Silk Grass Creek Reserve, P. H. Gentle 2987 (A);(ockscomb Branch. D. Stevenson 4 (F) Temax-Sarstoon N. .. Stevenson 164(F). Guatemala. Dept. El Peten: northeast of Poptun, F. B. Lamb 96 (F). Characteristics of this plant which place it in the genus Purdiaea andexclude it from the Clethraceae are as follows: a greatly exaggerated quin-cuncial type of sepal insertion, with the exterior sepals considerably largerthan and completely inclosing the interior sepals: an ovary composed of5 carpels and 5 locules, with each locule containing a single, pendulousovule; a single style with an unbranched stigma: and a dry. indehiscentfruit which is usually devoid of seeds. The pollen grains, also, are almostidentical in shape, size and structure to those of other species of Purdiaea.The Clethraceae, represented by the single genus Clethra, is characterizedby equal sepals, a 3-carpellate, 3-locular ovary with numerous ovules ineach locule, usually a 3-lobed stigma, and a loculicidal capsule with nu-merous small seeds. The Cyrillaceae and the Clethraceae have many characteristics in com-mon, however, and of the three genera in the Cyrillaceae, Purdiaea appearsto be the one most closely related to the Clethraceae. The inclusion of a[VOL. XLII
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