BOT. GAZ. 151(3):402-413. 1990. © 1990 by The UnlVerSJty of Chicago. All lights reserved. 0006-8071/90/5103-00 I1$02.00 REPRODUCTIVE AND VEGETATIVE EVIDENCE FOR THE OCCURRENCE OF CRUDIA (LEGUMINOSAE, CAESALPINIOIDEAE) IN THE EOCENE OF SOUTHEASTERN NORTH AMERICA PATRICK S. HERENDEEN* AND DAVID L. DILCHERr I *·tDepartmenls of Biology and tGcology. Indiana Unlversny, Bloomington, Indiana 47405 Fossil ,legume fruits and leaflets from twO localIlJes in the Middle Eocene ClaIborne Formation from western rennessee are dcscnbed and assigned 10 the extant panlropical genus Crudia (Caesalpinioldeae, Detaneae). Morphological and anatomICal features of the fruits and leaflets are used In evaluating the sys- temalK relallOnshJps of Ihese fOSSils. The fossils are more Similar to several Crudw specIes from tropical Amenca and Afnca than they are 10 the speeles Slndled from A",a. These fOSSils represent the onlv doe- umented occurrence of Crudia megafossils and eonflrm its existence by Ihe Middle Eocene. - Introduction . The Leguminosae (or Fabaceae) are a large and dt verse consisting of three subfami lies (Caesalpini6ideae, Mimosoideae, Papilionoideae) and approximately 650 genera and 18,000 species (POLHILL et al. 1981). The family has a cosmo- politan distribution and can be found in nearly all habItat types. Legumes may also he an ahundant and diverse component in Tertiary fossil floras. However, the published record of fossil legumes is largely unreliable because it contains numerous er- roneous generic identifications for many fossil le- gume leaflets and fruits. The great diversity of extant Leguminosae and the numerous cases of convergence among distantly related genera, par- ticularly in fruit morphology, necessitate extensive study of gross morphology, fine venation, and cu- ticular anatomy of extant fruits and leaflets before reliable determinations can be made for fossil specimens. The oldest fossil legumes reported are from the Maastrichtian. These arc Sindora-like pollen (Cae- salpinioideae, tribe Detarieae) (MULLER 198 L, 1984) and fossil wood assignable either to the Caesalpi- nlOldeae ?r to the Mimosoideae (Mimoxylon) (MULLER-STOLL and MADEL 1967; RAVEN and POLHILL L98 J), The oldest diverse assemblaoes of fossil legumes are from Eocene sediments. blages of fossil mimosoid pollen grains have been reported from Eocene and younger sediments of northern Africa (GUINET and SALARO-CHEBOL- DAEFF 1975; SALARD-CHEBOLOAEFF 1978; GUINET et aJ. 1987). However, the Eocene age presented by SALARD-CHEBOLDAEFF (1978) for this mimo- 'New address: DAVID DILCIIER, Flonda Museum of Natnral History. UTl)verslly of Florida. GalTlesvllk. Flonda 326ll. Manl/SCripT receIved Oerober 1989. reVIsed manl/SCripT re- relved April 1990 Address for COITespondence and reprints: PATRICK HEReN- DEEN, Department of Palaeobolany, Swedish Museum of Nat- ural History. Box 50007. S-104 05 Stock.holm, Sweden. soid pollen has been questioned (DAGl-lUAN et al 1980; CREPET and TAYLOR 1986). One of the most diverse assemblages of fossil legume megafossils comes from sediments of the Mississippi Embay- ment (Middle Eocene Claiborne Formation) in southeastern North America. This assemblage in- cludes fossil leaflets, fruits, and flowers (BERRY 1914,1916, 1924, 1930; CREPET and DILCHER 1977: DAGHLlAN et al. 1980; CREPET and TAYLOR 1985 1986; HERENDEEN and DILCl-lER 1988, 1989, 1990a: I 990b , 1991). The generic identifications of BERRY (1914,1916,1924,1930) are unreliable (DILCHER 1973, 1974) and many are in need of reevaluation. After an examination of the published specimens and new collections of fossils made over the past 30 yr, we currently recognize more than 25 types of fossil legume leaflets and al least 20 Iypes of fossil legume fruits representing all three subfamilies. These megafossils have been re- covered from 14 Eocene localities in western Ken- tucky and Tennessee and northern Mississippi. The fossil record of the Caesalpinioidcae is pri- manly based on reports of fossil pollen, although several reliable reports of caesalpinioid meoafos- sils are in the literature. Palynological evidence suggests that the Detarieae are represented early in the fOSSIl htstory of the family. Sill dora-like pollen (Loranthacites pilaws and L. catterallii) has been reported from Maastrichtian and younaer sedi- ments of Siberia, South America, and (V AN CAMPO 1963; KRUTZSCH 1969; SRIVASTAVA 1969; SOLE DE PORTA 1972; MEDUS 1975; SALARO-CHE- BOLDAEFf 1978; MULLER 1981) Pollen similar to Maniltoa (Detarieae) was described by ELSIK (1968) from the Paleocene of Texas. MULLER (1981) notes that this pollen (OacopolLeniles pariahilis Elsik) is also comparable to that of Elizabetha and Pelto- gyne. Coarsely striate pollen identified as Crudia has been reported from the Paleocene of Nigeria (ADEGOKE et al. 1978) and the Eocene of Panama (GRAHAM 1985) and South America (MULLER 1981, 1984). Caesalpinia-type pollen (Margocolporires 402