294 TRANS. ST. LOUIS ACAD. SCIENCE. 



eventually a cespitose appearance. Polyanthes behaves just in 

 this manner. 



The subterranean trunk of most (or all ?) Agaves contains, like 

 that of Yuccas and many other plants of these families, a great 

 deal of mucilage,* which, mixed with water, has detergent quali- 

 ties to a considerable degree ; these "roots" and the whole plants 

 thus used are known to the Mexicans by the name of Amole. 

 Another use is made of the trunk, when, before flowering, it 

 has developed a large quantity of saccharine matter, for nourish- 

 ment ; and not only the trunk of Mexican Agaves, but also that 

 of the larger Arizona species, is thus eaten, after baking, under 

 the name of Mezcal, and is said to be a very savory dish. The 

 name Maguey is more commonly used for the plant itself. 



LEAVES. 



The leaves of the Agaves are sessile with a broad sheathing 

 base, from linear to lanceolate or even ovate, the broader ones 

 contracted above the base, and widened again upwards. They 

 are thick and fleshy, sometimes soft, but usually of a firmer tex- 

 ture, rarely quite tough and hard ; in some species (only in the 

 first group) they decay at the end of the season, but in most Aga- 

 ves they are persistent for years. 



The margin of the leaf usually bears hard and dark-colored 

 straight or hooked or variously flexed spiny teeth ; sometimes it 

 is denticulate with minute, pale teeth ; rarely it dissolves, Yucca- 

 like, into threads ; in our A. parvijiora it combines the teeth on 

 the lower half with the fibres on the upper half of the leaf; very 

 seldom the edge of the leaves is entire ; in some species the whole 

 margin of the leaf bearing the spines becomes dry, hard and 

 horny, and is eventually, together with the spines, detached from 

 the leaf (A. heteracantha). It is not well-known whether the 

 spines, so much relied on to characterize the different forms, are 

 sufficiently constant ; it seems, at least, that an extensively culti- 

 vated form of A. rigida, of Yucatan, has lost its spines, and 

 produces them only occasionally and very sparsely : in the allied 

 genus Fourcroya, leaves with and without marginal spiny teeth 

 are of common occurrence. 



* The suggestion made (p. 21) that the rootstock may contain saponine, has not been 

 verified by chemical analysis. 



