Revision of Chlorophora (Moraceae) in America

After several pre-Linnean mentions (see: Bureau 1873), the name Morus tinctoria for plants belonging to the present genus Chlorophora was first validly published by Linnaeus (1753). Later combinations were made under Broussonetia Ventenat by Kunth (1817), under Fusticus Rafinesque by Rafinesque (1838), and under Maclura Nuttall by D. Don ex Steudel (1841). Rafinesque (l.c.) based the genus Sukaminea on Moms tinctoria L., without mentioning any species. Gaudichaud (1830) established the genus Chlorophora, based on Morus tinctoria L. Sp. PI. 1753. The valid combination Chlorophora tinctoria (L.) was made by Bentham, who added the African Morus excelsa Welwitsch to Chlorophora (Bentham et Hooker 1880). Recently Corner (1962) made the combination Maclura tinctoria again, when reducing the genera Cudrania Trecul, Cardiogyne Bureau, and Chlorophora Gaudichaud to sections of Maclura Nuttall. Beside C. tinctoria several other species were described, e.g. Maclura chlorocarpa Liebmann, Maclura affinis Miquel, Maclura mora Grisebach, Chlorophora mollis Fernald. Especially Bureau (l.c.) and Hassler (1919) distinguished several infraspecific taxa. Woodson, Schery et coll. (1960) distinguished only one American Chlorophora species, C. tinctoria. It seemed worth-while to investigate with ample material how many species and infraspecific taxa there are.