56 HOUGH'S AMERICAN WOODS. 



3-celled, ovules two-many. Fruit a 3-celled capsule or berry with usually ana- 

 tropous or amphitropous seeds containing small embryo inclosed in copious 

 albumen. 



A very large and important order of mostly herbaceous (rarely woody) plants 

 noted for their beauty and the fragrance of their flowers, for medicinal proper- 

 ties or for food. 



GENUS YUCCA, LINNAEUS. 



Leaves numerous, alternate, thickly clustered at the summit of the stem, linear- 

 lanceolate, with broad clasping base, then abruptly narrowing and becoming widest 

 at about the middle, tipped usually with a sharp, horny point, thick and rigid (some- 

 times thin and flaccid), more or less concave above and convex below, smooth or 

 scabrous, with margin entire, serrulate or filamentose and separating into threads, 

 exstipulate, involute in the bud, erect at first but finally reflexed and long per- 

 sistent; buds naked, flattened-ovoid, acute, in the axils of the leaves. Flowers 

 in large compound many-flowered terminal bracteate panicles (or occasionally 

 simple racemes or spikes), perfect, expanding in the evening for a single night, 

 entoniophilous, odorous; perianth six-parted, with segments in two series more 

 or less united at base, thick, ovate-lanceolate, pure white or tinted, those of the 

 other series smaller and more colored, finally withering and persisting afterwards; 

 stamens six in two series, hypogenous, usually shorter than the ovary, with rather 

 fleshy filaments, at first erect and finally recurved, anthers introrse, attached on 

 the back, 2-celled, the cells opening longitudinally and curling backward to expel 

 the pollen; ovaries superior, usually sessile, nectiferous, white, glabrous, three- 

 celled, with three-lobed style, the lobes emarginate at apex, ovules numerous in 

 each cell. Fruit baccate and indehiscent or capsular and dehiscent, six angled, 

 six-celled, usually beaked at the apex and surrounded at base with the rudiments 

 of the perianth; seeds compressed-triangular, or obovate to orbicular, with thin 

 black testa; embryo straight or more or less curved, diagonal in hard albumen. 



A New World Genus represented in the southern United States by a dozen 

 species, eight of which assume the habit of trees. Several species are popular in 

 cultivation on account of their beautiful waxy white flowers and singular habit 

 of growth. The name, Yucca, is said to be derived from the Carib name of the 

 root of the Cassava. 



175. YUCCA ARBORESCENS, TRELEASE. 

 TREE YUCCA, JOSHUA TREE. 



Ger., Baumartige Yukka; Fr., Yucca dSarbre; Sp., Yucca 



arborizada. 



SPECIFIC CHARACTERS: Leaves lanceolate, very rigid, concave above the mid- 

 dle, imbricated and densely crowded at the ends of the branches, lustrous reddish 

 brown at base, 5-8 (or on vigorous shoots 10-12) in. in length and - in. in width, 

 at base from --2 in. in width, glaucous, bluish-green, smooth or nearly so, taper- 

 ing to a sharp dark brown point and with thin yellowish margin serrated with 

 minute sharp teeth. Flowers (March to May) in dense nearly sessile pubescent 

 panicles, 15 or 16 in. long and about half as broad, with stout rachis l in. thick 

 at base, from conspicuous cone-like buds 8 or 10 in. long formed by the closely 

 imbricated leathery cream-white bracts; lowermost bracts sterile and more 

 resembling the leaves, those above ovate-oblong, acuminate, large below (7-8 in. 

 long), and successively smaller above; flowers 1-2 in. long, globose to oblong, 

 waxy greenish- white, with strong rather disagreeable odor ; segments of perianth 

 thin below, thicker, incurved and concave above, glabrous inside, with a few 

 hairs at base and apex, pubescent outside: stamens about half as long as ovary, 

 filaments clavate, papillose; ovary conical, sessile, three-lobed above the middle, 

 light green, with nearly sessile six-lobed white stigma having a wide stigmatic 

 canal. Fruit ripens in May or June, then spreading or somewhat pendent bac- 

 cate, ovate-oblong. 2-4 in. long, acute, slightly three-angled, tipped with the 

 stigma and surrounded at the base by the remnant of the perianth, light brown 



