160 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 54. 



Order POLEMONIALES. 



Family BIGNONIACEAE. 



Genus JACARANDA Jussieu. 



JACARANDA POTOSINA, new species. 



Plate 18, fig. 14. 



Description. — Leaflets small and thin, subsessile, lanceolate in out- 

 line, with a bluntly pointed apex and a narrowly cuneate base. 

 Margins entire. Length, about 1.5 cm. Maximum width, midway 

 between the apex and the base, about 3 mm. Petiolule very broad, 

 short, 1 mm. or less in length, trmicate. Midrib attenuated distad, 

 broad in the lower half of the leaflet, expanding rapidly proximad to its 

 jmiction with the petiolule with which it is contmuous. Secondaries 

 thin, numerous, ascendmg; they diverge frgm the midrib at acute 

 angles subparallel with one another and the lateral margins and are 

 connected by straight oblique tertiaries. 



This well marked new form is referred with some hesitation to the 

 genus Jacaranda, agreemg with the leaflets of several of the existing 

 pinnate leafed species with tiny leaflets, as for example, Jacaranda 

 caroliniana Pohl or Jacaranda cuspidifolia Martius. 



The genus Jacaranda comprises about two score existing species of 

 shrubs of the campos and trees. It is confined to tropical America 

 and ranges from Bermuda to Brazil, and is abundant in the Amazon 

 basin. The only other known fossil species is one based upon both 

 leaflets and seeds described by Ettingshausen ^ which Schenk ^ thinks 

 is of doubtful identity. There are poorly preserved specimens of 

 several varieties of winged seeds present in the Potosi collections, but 

 none of these can be conclusively referred to the Bignoniaceae. 



According to Herzog ' Jacaranda cuspidifolia occurs in the vicinity 

 of Santiago and San Jose and in the hill country of Velasco and a 

 second species is found in the broken woods along Rio Pirai and Rio 

 Yapacani, all localities in eastern Bolivia. 



Holotype.—Csit. No. 35116, U.S.N.M. 



» Ettingshausen, C. von. Die tertiare Flora von Haring in Titol, 1855, p. 59, pi. 20, figs. 12-20. 



' Schenk, A., Palaeophytologie, 1890, p. 779. 



3 Herzog, Th., Pflanzenformationen Oat Bolivias, vol. 44, 1910. 



