C(>:\ipo^ni()\ oi' rill'. i'L(ii;.\. 



79 



This form lias a imicli narrower raiifjc than its 

 kin beyond tiie Pacilic. Orcoiiiunnea is very 

 close to Engclliardtia, and by the pideobotanist 

 the two may be (•t)nsi(hTed as identical," for 

 thoy represent slifiiitly modified descendants of 

 a common ancestor which was of cosmopolitan 

 (HstributioTi dnrinj;; the (»arly 'r<'rliar\-. 'V\\v 

 present isolation of Oreonuumea fnrnisiies a 

 striking illustration of the great changes which 

 have taken place in the flora of th(> world in the 

 relatively short time, geologically s])eaking, 

 that has elapsed since the dawn of I Ik^ Tertiary. 

 Wlien elosc^ly relat«!d forms in tlie existing 

 flora of the world are restricted in ran<r<i and 



of JMigelliardtia, were obtaini^l for the largc^r 

 European herbaria, and Baron Kttingshausen, 

 that most sagacious of pahiobotanists, as long 

 ago as 1S51 pointod out that certain supposed 

 s])ecies of ('arjnnus were nially fniits of I'^ngeL- 

 luirdtia. lie rciturned to the subject in 1S5S 

 without, however, actually <-hanging tlie names 

 of any of the supposetl species of Carpmus, nor 

 does he seem to have been aware of the ])res- 

 enco of a living species of Kngelliardtia (Oreo- 

 mumiea) in Central America. 



Suico Ettingshauson's amiomicement a do/<!n 

 or more fossil species of i<^.ng<ilhardtia have 

 l)C(in (l(!scri1)(Hl. Th<i old(wt known JMUdpcMn 



Figure 4. — Skelcli mapslmwinj^ areas of distribution of recent (solid Mack) niul frssil (lined) species of Juplans. A South j\nieric:n species 

 found near Bahia, Bnizil, and the existiuj; Japanese species are not shown. 



isolated from their nearest relatives, or wIumi 

 other existing genera are monotyj)ic, it is tpiilo 

 safe to predicate for them an interestuig and 

 extended geologic history. Engelhardtia is an 

 illustration of tliis jn'uiciplc, for its peculitir 

 three-wmgod fruits have Ixnin known iji the 

 fossil state for almost a contiuy. They w(U'<i 

 long imrecognized, however, and the earli(U- 

 students who descrilied th(\m c()mj)ared th<Mn 

 with the somewhat similar winged fruits of tlui 

 genus CarpLnus (Betidacea;) . As a residt of 

 the liotanic exploration of distant lands hi the 

 early part of the nineteenth century specimens 



' Many students of recent floras, as. for example. TTetnsle}-, in his Flora 

 of Central .\merica, consider Kngelhardtia and Orcomunnea as one 

 genus. 



form occm-s in tJu> lower Oligocene (Sannoi- 

 sia.n) of France and the species become increas- 

 ingly abiuidant tliroughout southern Eurojxv, 

 <!s])ecially toward the close of the Oligocene 

 ami th3 dawa^ of the Miocene. vSaporta says 

 tliat the slabs from the ksaf beds at Annissan, 

 in southeast;<*rn France, are thickly strewn 

 with these ])eculiar fruits. Fossil forms are 

 foimd m Em'opo tlu'ougliout the Mioceiio and 

 Pliocene, and specimens of late Miocene or 

 early Phocone age are riicorded from S|)ain, 

 France, Italy, Croatia, and Hmigary. The 

 Wil(U)X species are somewhat older thaji any of 

 the P^urojx^an forms. 



The accompanying sketcli map (fig. 5) sliows 

 the present distribution of Engelhardtia in tJie 



