436 
1. H. parviflora (Torr.) Stem 6 to 12 din. high, sparingly branched: leaves 
crowded, 3 to 6 din, long, 6 to 8 mm, broad, recurved, long-attenuate : bracts broad 
and acuminate, rather large: pedicels cymose-fascicled (1 to 3.5 em, long): flowers 
(12 min. long) with erect segments: stamens shorter, with small anthers (2 mm. 
ing): style exserted, two or more times longer than the ovary: pod ovate, acute, 
2.5 em. long. (Yucca (2) parviflora Torr. Aloe yuceafolia Gray. H. yuceafolia 
Engelm.)—Western Texas, from Frio County to the Pecos, 
2, H. Engelmanni Krauskopf, of the same region, is not so well known, but may 
be distinguished by its more slender and flexuous branches, smaller bracts, twice 
longer anthers, and the stouter included style scarcely longer than the ovary. 
10. YUCCA L. (Brar-GRAsS, SPANISH BAYONET.) 
Stems woody, either very short or rising into a thick and cotumnar 
palin-like trunk bearing crowded linear-lanceolate spinescent (at apex) 
thick leaves and a racemose panicle of tlowers with white or whitish 
campanulate perianth with ovate-lanceolate many-nerved segments, 
clavate papillose filaments with small anthers, stout persistent style 
(or none), emarginate stigmas more or less connate into a stigmatic 
tube, and the narrowly oblong fruit berry-like or a septicidal or locu- 
licidal incompletely 6-celled pod.—The pollination of the species 
of Yucca by moths of the genus Pronuba is one of the most wonderful 
chapters in the history of pollination. 
*Hruit berry-like, pendulous: seed thick, rugose, not margined: mostly arborescent, with 
sessile panicle. 
1. ¥. Treculeana Carr. Caudex 18 to 75 dm. high, branching at top: leaves 
very long (7 to 13 dmm,), straight, very rigid, deeply channelled, rough on back, 
with entire margins: panicle subsessile, ovate, 6 to 12 dim, long, densely flowered, 
nearly glabrous; bracts large, ovate or broadly lanceolate: flowers cream-white ; 
segments ovate or ovate-lanceolate, acute or acuminate (3 to 5 em, long): filaments 
scarcely papillose, equaling the pistil: style slender: stiginas narrow, deeply 2-lobed ; 
fruit sub-cylindric, strongly beaked, 7 to 10 cm, long: seeds 6 to 7 mm. broad. (Y. 
canaliculata Hook.)—-Southern and southwestern Texas to northern Mexico. 
”» ¥. baccata Torr. Caudex short or none: leaves coarsely filamentous on mar- 
gin, very thick and rigid (4 to 12 dm, long by 2.5 to 5 em, broad), channeled or 
concave, rough, especially on the back, tipped by a very stout brown spine: panicle 
pedunculate, usually glabrous, with ovate-lanceolate or ovate bracts: perianth-seg- 
ments narrow, 6to 7.5 cm. long: stamens equaling the ovary: style slender: fruit 
oval or eylindrie (7 to 12 em. long), dark purple, often long-beaked: seeds 8 to 16 
mm. broad.—From western Texas to southern Colorado. ‘The roots of this as well 
as of the three following species are used for ‘“amole” by the Indians and Mexicans. 
8, ¥. australis (Engelm.) Trelease. Resembling the last, but with a taller branch- 
ing candex (generally 3 to 4.5m, high), thinner very concave leaves entirely smooth 
(or only slightly seabrous on the back) and with finer fibers, smaller flowers (3 em, 
long) with ovate segments, and short style. (Y. baccata, var. australis Engelm.)—A 
species of the nothern highlands of Mexico and extending into the elevated Sierra 
Blanea region of southwestern Texas. 
** Fyuit capsular, crect: seed thin, smooth, broadly margined: caudex none or short, 
the panicle upon a tall scape. 
+ Leaves serrulate. 
4. ¥. rupicola Scheele, Acaulescent: leaves 3 to 6 din, long, 2.5 to 5 em. wide, 
rigid, erect, pungent, smooth, deep green, mostly oblique and undulate or twisted 
with coarse reddish serratures: scape 12 to 21 dm, high, with long and narrow, 
