170 DRACAENACEAE 



Fruit a dry capsule. 



Leaves narrowly linear, very long. 



Style stout, swollen, green. 1. Y. glauca. 



Style not swollen, white. 2. Y. angustissima* 



Leaves linear-lanceolate, short; style not swollen, white. 



Leaves not papillose. 3. Y. Harrimaniae. 



Leaves densely rough-papillose at least on the back. 4. Y. Gilbertiana. 



Fruit fleshy. 5. Y. baccata. 



1. Y. glauca Nutt. Subacaulescent or branching with decumbent stems; 

 leaves rigid, 6-12 mm. wide, 2-4 dm. long, white-margined, finely but sparingly 

 filiferous; inflorescence 1-2 m. high, simple or somewhat branched; sepals and 

 petals greenish white, oval to lanceolate, acute, 4-5 cm. long; capsule oblong, 

 usually not constricted, somewhat roughened, brown. Y. angustifolia Pursh. 

 Plains and hillsides: la. Tex. 'Ariz. Mont. Plains Submont. My-Jl. 



2. Y. angustissima Engelm. Acaulescent, with a thick horizontal root- 

 stock; leaves 2-4 dm. long, 2-5 mm. wide, pungent, white-margined, very freely 

 curly-filiferous; inflorescence 1-1.5 m. high, racemose, or short-branched below; 

 sepals and petals rather short, lanceolate, acute; capsule scarcely 5 cm. long,, 

 rough, brown, constricted in the middle. Desert regions: Ariz. s Utah. L. 

 Son. 



3. Y. Harrimaniae Trelease. Acaulescent, often cespitose; leaves linear to 

 lanceolate, 6-40 mm. wide, rigidly spreading, glaucous or green in age, pungent, 

 narrowly brown-margined, with coarse curled fibers; inflorescence 2.5-5 dm. high, 

 simple; sepals and petals greenish, oval, obtuse or acute; capsule brown, broadly 

 oblong, about 4 cm. long, constricted. Dry regions: Utah w Colo. w N.M. 

 Son. Je. 



4. Y. Gilbertiana (Trelease) Rydb. Acaulescent; leaves linear, about 4.5 

 dm. long, 2 cm. wide, openly concave, glaucous at least on the upper side, pun- 

 gent, fibrous-filamentose on the margin; flowers about 4 cm. long; segments nar- 

 row, acute; ovary papillate; style oblong, pale. Y. Harrimaniae Gilbertiana 

 Trelease. Dry regions: w Utah. Au. 



6. Y. baccata Torr. Low, usually with stout prostrate branched caudex; 

 leaves rigid, spreading, about 6 dm. long and 5 cm. wide, concave, shagreen- 

 roughened, with narrow brown margins, coarsely filiferous; sepals and petals 

 lanceolate, about 7.5 cm. long; style slender, elongate; fruit large, sometimes 

 2 dm. long, oblong- or conical-ovoid, pendent, fleshy. Dry plains: Tex. & 

 Colo. Nev. Son. Submont. Ap-Je. 



2. CLISTOYUCCA (Engelm.) Trelease. JOSHUA TREE. 



Large tree. Leaves short, thick, not filiferous. Flowers in panicles. Sepals 

 and petals each 3, thick, incurved at the end. Stamens 6, hypogynous; filaments 

 thick, curved outward; anthers sagittate, horizontal. Ovary 6-celled; stigma 

 sessile, 6-lobed. Capsule 6-celled, spongy, indehiscent. Seeds numerous, flat, 

 thin. 



1. C. brevifolia (Engelm) Rydb. A tree 5-10 m. high, with rough bark; 

 leaves 1.5-2 dm. long, 6-15 mm. wide, rough, serrulate on the margin, spine- 

 tipped, concave above; flowers in sessile short panicles; perianth campanulate, 

 4-6 cm. long, greenish white; capsule 5-7 cm. long. Yucca brevifolia Engelm. 

 Y. arborescens Trelease. C. arborescens Trelease. Desert regions: s Calif. s 

 Utah Ariz. Son. 



3. NOLINA Michx. 



Coarse herbs, with woody caudices. Leaves crowded, rigid, narrow, entire 

 or serrulate, keeled, pungent-pointed. Flowers polygamo-dioecious, in open 

 panicles. Sepals and petals each 3, distinct, 1-nerved, similar, white. Stamens 

 6, reduced to staminodia in the fertile flowers; filaments thick, short. Ovary 

 3-celled, abortive in the staminate flowers; styles obsolete during anthesis. 

 Ovules 2 in each cavity. Capsule dry, 3-winged, tardily and irregularly open- 

 ing. Seeds often solitary, thick. 



