224 MISSOURI BOTANICAL GARDEN. 



the " squaw corn " of the Indians. In aloifolia, where the 

 pulp becomes almost black throughout, the very slight core 

 also at length becomes pulpy. These fruits are well adapted 

 to dissemination by fruit-eating animals, especially birds, the 

 firm core suggesting that the pulp only is swallowed, the 

 seeds being thrown away; but I do not know of any 

 recorded observations on their dissemination. 



The Clistoyuecas, with dry indehiscent fruits, comprise 

 the curious tree Yucca of the deserts, Y. brevifolia, and a 

 single eastern species, Y. gloriosa. Though frequent in 

 cultivation, the latter is one of the least known Yuccas, and 

 its fruit has been observed rarely. All that I can learn of 

 it points to the conclusion that its fruit is of the Sarcoyucca 

 type with rather thin seeds and suppressed development of 

 the exocarp, suggesting a retrogression from aloifolia; but 

 nothing can be said as to its dissemination. Y. brevifolia, 

 however, differs from all of the other known species in 

 having a very thick exocarp, corresponding to the pulp of 

 the preceding group, but dry and spongy at maturity. 

 The fruits of this species fall quickly after ripening, either 

 by a distinct disarticulation or because of the brittleness of 

 the pericarp at base, and their rounded form and very light 

 specific gravity render them well developed "tumble 

 fruits," and point to their dissemination over the dry 

 sands of the desert by aid of the strong winds which prevail 

 there, the seeds being liberated ultimately by the breaking 

 of the fragile pericarp. Although brevifolia appears to be 

 the least advanced of the Yuccas in its general development, 

 I am disposed to look on this adaptation of its fruit to 

 wind dissemination as a special acquisition, rather than 

 regard it as representing the original type of Yucca fruit ; 

 yet, so far as the facts are known, it might equally well 

 be held to be an advance on an earlier unspecialized fruit, 

 or a retrogression from the baccate type. 



In the capsular species, the green exocarp dries down to 

 a rather thin layer at maturity, and the core, with this 

 adherent film, dehisces through the true septa, and, for a 



