130 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.54. 



thin, scarcely distinguisable from a secondary which diverges from 

 it at an acute angle at the base and sweeps upward nearly to the tip 

 where it becomes lost in the tertiary areolation made up of acute 

 proximal forks and distal camptodrome arches. 



This pecuhar species is abundant at Potosi and it appears to be 

 identical with the single leaflet imperfectly figured by Engelhardt. 

 In one case a pair of terminal leaflets are preserved in attachment, 

 showing that the leaves were even pinnate. The majority of the 

 leaflets approach the maximum of size and often fail to show the 

 characteristic venation, which I assume was the case in the leaflet 

 figured by Engelhardt. This venation is characteristic of certain 

 modern species of Acacia and Calliandra and resembles modern 

 species hke Acacia Roemeriana, Acacia fasciculata Kunth ^ of Brazil 

 or Acacia crassi folia A. Gray of Mexico. 



Plesiotype.—Ciit No. 35087 to 35089, U.S.N.M. 



ACACIA TENUIFOLU Engelhardt. 



Acada tenuifolia Engelhardt, Sitz, Naturw. Gesell. lais in Dresden, 1894, Abh 1 

 p. 11, pi. 1, figg. 45, 46. 



i>€Scn^iion.— Leaflets small, sessile, oblong lanceolate, nearly equi- 

 lateral, equally acutely pointed at both ends. Margms entire. 

 Length, 1 to 1.25 cm. Maximum width, in the middle part of the 

 leaflet, 4 to 5 mm. Midrib thin, straight. Secondaries about five 

 thin camptodrome pairs. 



^ This species is only doubtfully represented in the present collec- 

 tions. It is compared by Engelhardt with the existing Acacia 

 pedicellata Bentham of eastern Bolivia and Brazil. 



Genus INGA Willdenow. 



INGA OCHSENIUSI Engelhardt. 



Plate 15, fig. 19. 



Inga ochseniusi Engelhardt, Sitz. Naturw. Gesell. Isisin Dresden, 1894, Abh. 1, 

 p. 11, pi. 1, figs. 39, 40. 



^ Description. — Leaflets small, sessile, inequilateral, eUiptical in out- 

 line, nearly equally rounded at both ends, but the base much more 

 inequilateral than the apex. Margins entire. Texture coriaceous. 

 Length, about 11 mm. Maximum width, about 5 mm. Midrib 

 stout, curved. Secondaries thin, numerous, camptodrome; those on 

 the narrower side of the leaflet more ascending and forming a more 

 acute angle with the midrib than those on the broader side. 



^ This species was described by Engelhardt and has not been recog- 

 nized in the other collections from Potosi. It was compared Vvdth 

 the existing Pithecolohium diversifolmm Bentham, Inga fiabelliformis 



> This species is usually known as Mimosa fasciculata . Bentham having transferred it to the genus Mimosa 



