284 



FLORA AND SYLVA, 



PROFESSOR TRELEASE ON 

 YUCCA. 



(Continued from page 254.) 



T. Louisianensis (Trelease). — The aspect of 

 the preceding, or, when the inner leaves are 

 dilated, of T. jilamentosa media. The flaccid 

 green leaves from less than half to (rarely) as 

 much as \\ inches wide, white bordered, spar- 

 ingly filiferous. Inflorescence an exserted gla- 

 brous or mostly pubescent panicle. Petals broad 

 to attenuate. Style variously tumid and deep 

 green, to pale and oblong. Capsule stout and 

 short, angular in developing, as in T.jiaccida ; 

 where this has been long cultivated with T. 

 rupicola spontaneous hybrids occur, with the 

 leaf margins neither denticulate or filiferous. 



T. rigida (Engelmann). — Caulescent, 

 reaching 1 o to 1 5 feet, simple or elongately few 

 branched above. Leaves glaucous, thin but 

 rather rigidly spreading, about an inch wide, 

 mostly concave, often with scabrid ridges, 

 slender tipped but very pungent, the yellow 

 margin minutely denticulate. Inflorescence 

 rather large, panicled close to the branches 

 glabrous. Flowers not very large. Capsule ob- 

 long, thick-walled, rough, not constricted, the 

 flat valves tipped with short outturned points : 

 seeds very dull. South of Torreon, along the 

 Mexican central railroad this small tree is abun- 

 dant, on the rocky hillsides, and conspicuously 

 contrasted with accompanying T. Treculeana 

 by its very glaucous narrower foliage. It may 

 be that small trees, visible from the Mexican 

 national railroad, extend its range to the east. 

 It is one of the handsomest tree Yuccas in its 

 foliage ; the slender trunks are commonly sim- 

 ple, but occasionally once or more forked. 



T. rupicola (Scheele). — Acaulescent. 

 Leaves glaucous, pungent, firm or flaccidly 

 spreading, often twisted, 1 to nearly 2 feet long 

 and an inch or more wide, the yellowish, finely 

 denticulate margin soon turning brown. In- 

 florescence glabrous, panicled mostly above the 

 leaves. Flowers white or greenish : style white 

 or greenish, oblong, often three-sided. Capsule 

 thin walled, with flat or concave mucronate 

 valves : seeds rather dull. From south-central 

 Texas south-westward, probably across the 

 boundary. One of the early discoveries of 

 Lindheimer and Trecul, sufficiently distinct 

 from all its congeners. 



T. rostrata (Engelmann). — Of the aspect 

 of T. radiosa. Caulescent, at length 9 or 1 o feet 

 high, or short-branched at the crown. Leaves 

 very numerous, rigidly divergent, one-third of 

 an inch wide, a little glaucous, flat or biconvex, 

 straight, thin, very pungent, the yellow mar- 

 gin minutely denticulate. Inflorescence ample, 

 with sub-included base or mostly exserted, gla- 

 brous. Flowers white, umbonate at base : style 

 white, attenuate. Capsule oblong-ovoid, thick- 

 walled, with convex valves long-attenuate and 

 spreading above : seeds rather dull. Northern 

 Mexico. It is loosely rooted in the soil, so that 

 large plants are easily removed. The trunks 

 vary in height from about 1 to 10 feet, the 

 usual height being about 6 feet, and the wood 

 is extremely soft and spongy. When the old 

 leaves are removed, the diameter of the stem 

 is usually 6 or 8 inches, and it is not dilated 

 except where the roots start from the base ; of 

 somewhat the aspect of T. radiosa, but with 

 more rigid and denticulate not filiferous leaves, 

 this species rivals in gracefulness of habit the 

 Nolinas of Mexico and the Grass-trees {Xan- 

 thorrhcea) of the South Sea, both of which it 

 far surpasses in beauty of inflorescence, and it 

 should prove a desirable addition to regions 

 like California, Madeira, and the Mediterra- 

 nean countries, where it will prove hardy. 



T. gigantea (Lemaire). — A rough-barked 

 branching tree 30 feet or more high. Leaves 

 rigidly spreading or somewhat flexuous, green, 

 glossy, plicate, with soft green tip, over 3 feet 

 longand often 3 inches wide, scabrid margined. 

 Inflorescence compact, close to the leaves. 

 Flowers resembling those of T. g/oriosa. Fruit 

 apparently soon drying. This species, if more 

 than a form of V. e/ephantipes, was first described 

 from young specimens cultivated in European 

 gardens, and again, in mature form, from a 

 large tree cultivated in the Azores. It is not 

 known in a state of nature. In habit and foli- 

 age, except for larger dimensions, it resembles 

 T. elephantipes and is probably a form of it. 



T. g/oriosa (Linnaeus). — Shortly caulescent 

 and cespitose, or the trunk high and with se- 

 veral branches. Leaves slightly glaucous when 

 young, smooth or the dorsal lines roughened, 

 rather thin, but rigid, often concave near the 

 inrolled pungent, usually dark apex, about 18 

 inches wide, the usually brown margin at first 

 with a very few rarely persistent minute teeth, 



