COROCORO COPPER DISTRICT OF BOLIVIA 95 



Genus Mimosa LINNE 

 Mimosa arcuatifolia ENGELHARDT 



Mimosa arcuatifolia Engelhardt, Sitz. Naturw. Gesell. Isis in 

 Dresden, 1894, Abh. i, p. 10, pi. i, figs. 52-54. 

 Berry, Proc. U. S. Natl. Mus., vol. 54, p. 132, pi. 15, fig. 21, 1917. 



Description. Leaflets small, sessile, linear-lanceolate 

 arcuate, inequilateral, with a bluntly pointed apex and base, 

 the latter slightly wider than the apex. Margins entire. 

 Texture subcoriaceous. Length 3 to 4 mm. Maximum 

 width, in the middle part of the leaflet, about i mm. Vena- 

 tion obsolete except for the thin arcuate midrib. 



This species is fairly abundant at Potosi and occurs also 

 in considerable abundance at Corccoro. It is distinguished 

 with difficulty from the smaller leaflets of the more abundant 

 Calliandra obliqua, with which Engelhardt in all probability 

 confused it. The present species is, however, less linear, 

 somewhat more slender and arcuate, with a less oblique 

 base, and lacks the three primaries of Calliandra obliqua. 

 According to Engelhardt it is very similar to the existing 

 Mimosa invisa Martius, which ranges from southern 

 Mexico and the West Indies to Brazil, or Mimosa lupulina 

 Bentham of the last region. It may also be compared with 

 Mimosa microcephala Bonpland and with Mimosa pecti- 

 nata Kunth. It has also less aptly been compared with 

 the existing Parkinsonia aculeata Linnaeus. It may be 

 exactly matched by an undescribed recent species of Mimosa 

 collected by the writer at elevations of about 9,000 feet in 

 the Quimsa Cruz range in Bolivia. 



