4<5 TRANS. ST. LOUIS ACAD. SCIENCE. 



This remarkable Yucca makes considerable trees, 15-20-30 

 feet high ; the stout rough-barked trunks, often 1-2 feet in diame- 

 ter, 3-10 feet high, before they send off the long and numerous 

 branches, of which, in a very characteristic photograph, I have 

 counted 23 large and small ones. Leaves stiffer, harder and 

 rougher, and perhaps shorter than in any other species, some- 

 times only 3-4, usually 6-S, and rarely, in young and vigorous 

 specimens, even 10-12 inches long, 3-6 lines wide, not at all 

 narrowed above the base, glaucous, very rough on both sides, 

 with small but stout whitish or brown teeth on the edge, and a 

 stout and sharp brown point. The flower is said to be small and 

 white. A fruit before me is evidently erect, as the fragment of 

 the branch to which it is attached indicates, oval, slightly 6- 

 sided, pointed but not rostrate, and tipped with the well-preserved 

 short, sessile stigmas. The fruit is light and perfectly dry, the • 

 brown somewhat spongy fragile pericarp 2-3 lines in thickness. 

 Seeds large, 11-12 mm. in diameter, 2-2$ mm. thick, with a nar- 

 row margin and an even, not ruminated, albumen. In both the 

 fruits, I have been able to examine, the traces of the moth Pronuba 

 are apparent by the perforated rind and gnawed seeds or their 

 empty ring-like rims. 



C. Ch^enoyucca : fructus capsularis, erectus, septicide dehiscens, 

 demum apice 6-valvis : semina tenuia plana, latius marginata, 

 albumine integro. — Acaules vel vix caulescentes, panicula in 

 scapo elata. 



* Folia margine serrulato-asperata. 



9. Yucca rupicola, Schecle in Linncea, 23, p. 143, 1S50: 

 acaulis, foliis lineari-lanceolatis supra basin latiorem angustatis 

 canaliculatis supra planiusculis subtus convexis rigidis erectis 

 pungentibus ; scapo elato infra bracteis majoribus foliaceis ornato, 

 panicula pyramidali laxiflora bracteis parvis marcescentibus 

 stipata ; florum majorum segmentis ovatis acuminatis nunc arista- 

 tis apice nudis, staminibus rectis demum patulis ovario ipso 

 sequilongis, stylo elongate ; capsula acuta seu rostrata nunc medio 

 constricta, seminibus angustius marginatis. — T. toriifolia, Lind 

 heimer in sched. 1846, T. lutescens, Carriere 1. c. vii. 579, ex- 

 Baker. 



Var. a. tortifolia: foliis saturate viridibus varie tortis undula- 

 tisve saepius obliquis dorso laevibus et capsulis cum seminibus 

 majoribus. 



