112 



At Zacapa, Guatemala, in the valley of the Motagua River, I saw 

 trees 30 to 40 feet in height. The stipular thorns are large, very 

 broad, usually very much flattened at their connate bases, and 

 suddenly tapering towards their points. The extrafloral nec- 

 taries are arranged as in the preceding species. The flower- 

 spikes are also cylindrical, but much more slender. The fruit, 

 too, is more slender and curved, with a shorter beak. When 

 mature it is brown and dry and does not contain an edible pulp. 



A. sphœrocephala Schlechtendal and Chamisso is a shrub 

 of about the same size as A. spadicigera. The stipular thorns are 

 also much as in this species, but usually smaller and of a paler 

 colour. The leaves are furnished with only a single nectary, 

 which is at the base of the petiole. The flower-spikes are glo- 

 bular, the fruit a dry, straight, brown pod, much more slender 

 than in spadicigera, and with a short beak or point. 



Bentham adopted the specific name spadicigera and sphœro- 

 cephala because he believed that both of these were included under 

 the Mimosa cornigera of Linné (1770, p. 677) and Willdenow 

 (1806). On turning to the Systema Naturae, however, we find 

 that M. cornigera L. was based on Jacquin's M. cornigera, 

 and this author's description clearly rules out A. sphœrocephala, 

 since the flowers are described as " in spicam aggregantur densam 

 cylindraceam," and the description of the fruits as " coriácea 

 pulpam continent butyraceam " shows that only the species 

 later described by Schlechtendal and Chamisso (1830) as 

 spadicigera can be meant. I do not hesitate, therefore, to substi- 

 tute A. cornigera for spadicigera, and shall henceforth refer to it 

 only under the former appellation. 



It is also possible, I believe, to identify with a reasonable 

 degree of certainty the species of some of the other early descrip- 

 tions. The earliest of all, that of Hernandez (1651), which 

 he cites under the name Arbor cornigera and under the native 

 Mexican name " hoitzmamaxalli," is evidently also A. cornigera, 

 since he mentions the " siliquas edules." The species, described 

 by CoMMELiN (1697), however, is A. sphœrocephala, because he 

 says that the flowers are " lutei, numerosi, in globulum, etc.," 

 and that the pods are " fragiles." The species observed by Belt 

 must have been A. cornigera and not sphœrocephala, as Schimper 

 infers (1888, p. 48), because Belt remarks that " at the base of 



