NO. 2229. FOSSIL PLANTS FROM BOLIVIA— BERRY. 147 



spaced, subparallel; six or seven pairs diverge from the midrib at 

 angles of about 45° and are camptodrome. Tertiaries obsolete by 

 immersion. 



This species is not micommon in the present collection. While 

 similar to several other fossil species fomid at Potosi, it may be dis- 

 tinguished from Acacia uninervifoUa Engelhardt by its petiolule, 

 greater width and fewer secondaries; from Enterolohium grandi- 

 folium Engelhardt by its petiolulc, its smaller size, more prominent 

 secondaries and more equilateral form; from Mimosites engelhardti 

 Berry by its wider, less elongated, and more lanceolate form, by its 

 petiolule and more prominent secondaries. According to Engelhardt 

 it is very similar to the existing BraziUan species Macliacrium crio- 

 carpum Bentham. This species is recorded by Herzog ^ from the hill 

 country of Velasco and from the broken woods along the Rio Pirai 

 and Rio Yapacani, in eastern Bohvia. 



The existing species of Machaerium comprise over 60 trees or liigh 

 climbing shrubs, with small pinnate leaves, confined to the American 

 Tropics, where they range from the West Indies and Central America 

 to southern Brazil. Their maximum display is iji the Amazon region, 

 and they do not appear to be represented in the present mountain 

 region of Bolivia. 



The known fossil species are few in number and comprise, in addi- 

 tion to the present form, three Oligocene and a Miocene species in cen- 

 tral and southern Europe. 



Plesiotype.~C&t. No. 35103, U.S.N.M. 



MACHAERIL'M MILLERI, new species. 



Plate 17, fig. 7. 



Description. — Leaflets petiolulate, oblong-obovate, nearh^ equi- 

 lateral, with a broadly rounded apex and a cuneate base. Margins 

 entire. Texture subcoriaceous. Length about 2 cm. Maximum 

 width, at or slightly above the middle, about 7 mm. Petiolule stout, 

 curved, 2 to 2.5 mm in length. Midrib stout, curved. Secondaries 

 thin, numerous; they diverge from the midrib at angles of about 45° 

 and pursue a nearly straight asceiiding course, forkijig and anasto- 

 mosing, and eventually lost in the camptodrome areolation of the 

 marginal region. 



This well-marked form suggests comj^arisons with various existing 

 species of Leptolohium and Platypodium, both of which are repre- 

 sented in the Potosi flora. The venation, however, appears to ally it 

 more closely with the reticulate veined species of Machaerium. It is 

 readily distinguished from the associated Machaerium eriocarpoides 

 Engelhardt, which is a lanceolate leaflet with relatively distant and 

 regularly curved camptodrome secondaries. Among other forms 



1 Herzog, Th., Pflanzenforraationen Ost Bolivias, Englers Bot. Jahrb., vol. 44, 1910. 



