113 



each pair of leaflets, on the mid-rib, is a crater-formed gland." 

 and the thorns in his figure (1874, p. 218) cannot be those of 

 A. hindsii. 



The three ant acacias are widely distributed in Central 

 America and Mexico, and A. spadicigera is also recorded from 

 Jamaica and the north coast of Cuba.^ All the specie> are 

 decidedly tropical and rarely grow above an altitude of 4,000 ft., 

 though they range from Panama to the states of Sinaloa and 

 TamauHpas in Mexico. In Guatemala and Mexico the\- are 

 common to both the Atlantic and Pacific littoral, but are absent 

 on the great central plateau. In Nicaragua and Costa Rica the 

 two littoral ranges are, of course, less clearly separated. Belt 

 found A. cornigera at Matagalpa in Central Nicaragua, and the 

 same species occurs in Costa Rica as high as Alajuela (about 

 2,000 ft.), but, according to my observations, does not grow in 

 the immediate vicinity of San José (3,868 ft.), or at Cartago 

 (4,500 ft.). 



In this extensive range the three species occuj)\- somewhat 

 dift'erent though overlapping stations. A. hindsii is known onl\- 

 from Guatemala and Mexico, ranging from near sea-level to 

 somewhat over 4,000 feet. On the west coast of Guatemala, 

 at least, it shows its optimum development at about 600 to 

 1,200 ft., and specimens are less abundant and more sporadic 

 at higher elevations. It seems to prefer rather dry regions, and 



1 There sceriis to be some doubt as to the indigenous occurrence of 

 any of the three ant acacias in the West Indies. Prof. N. L. Britton, of 

 the New York Botanical Garden, who has a very intimate acquaintance 

 with the flora of that region, writes me as follows : " As to your Acacia 

 question, I have no definite knowledge of the occurrence of any of the 

 three species you mention in the wild state anywhere in the West Indies, 

 but Acacia spadicigera has been found in Cuba by various collectors, 

 apparently always after cultivation, though it is just possible it may 

 be wild somewhere in that island. We have specimens from the vicinity 

 of Havana. I have examined the spines of this Cuban material, but I 

 have found no holes in them, and I myself have never seen the plant 

 living in Cuba." 



Brother Leon, of the order of Christian Brothers, whom 1 recently 

 met in Havana, informs me that he has had under observation a number 

 of Acacia cornigera trees in Cuba, and that lie has never found ants in 

 their thorns. A number of these, which he kindly forwarded to me, 

 are very large, unpcrforated, and normal in all respects. 



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