DRACAENACEAE 273 



FAMILY 6. DRACAENACEAE Link. YUCCA FAMILY. 



Shrubby plants or trees, with woody caudices which are generally copiously 

 leafy. Leaves alternate : blades narrow, firm or rigid, sometimes with marginal 

 filaments, often finely toothed. Flowers in racemes or panicles terminating scapes- 

 or scape-like stems. Perianth usually not colored. Sepals and petals 3 each r 

 but little dissimilar. Androecium of 6 stamens. Filaments distinct, sometimes 

 partially adnate to the perianth. Anthers 2-celled. Gynoecium of 3 united car- 

 pels. Ovary superior, 1-3-celled. Styles united, sometimes very short or obso- 

 lete during anthesis, but manifest in fruit. Ovules 2-severai, or many in each 

 cavity. Fruit a primarily loculicidal capsule, or berry-like and indehiscent. 



Flowers perfect. 1. YUCCA. 

 Flowers dioecious or polygamo-dioecious. 



Flowers polygamo-dioecious, in open panicles : ovary 3-celled : stamens included. 2. NOLINA. 



Flowers dioecious, in dense panicles : ovary 1-celled": stamens exserted. 3. DASYLIRION. 



1. YUCCA L. 



Large scapose or caulescent plants, with shorter elongated, sometimes horizontal, root- 

 stocks. Leaves firm or rarely thinnish : blades rather narrow, rigidly pointed, commonly 

 furnished with thread-like fibers along the edges, serrulate or entire. Flowers in terminal 

 racemes or panicles. Perianth usually white, drooping, subglobose to campanulate : sepals 

 and petals distinct or slightly united at the base. Stamens 6, hypogynous : filaments 

 enlarged above, shorter than the perianth. Ovary 3-celled, or imperfectly 6-celled or 1- 

 celled : style columnar or tumid. Ovules numerous in each cavity. Capsule dehiscent, or 

 berry-like and indehiscent. Seeds flattened or turgid. 



Fruit an erect, dry dehiscent capsule. 



Leaf-blades with several marginal fibers. 

 Style columnar, white. 



Leaves with blades of a lanceolate or spatulate type, marked with gray or brown near the mar- 



ginal fibers. 

 Leaf-blades short-attenuate : capsule evenly narrowed to the apex, the carpels evenly convex. 



1. Y. filamentosa. 

 Leaf-blades long-attenuate : capsule truncately narrowed to the apex, 



the carpels uneven or angulate. 2. Y. flaccida. 



Leaves with blades of a linear type, white-margined. 



Leaves pliable, grass-like, mostly recurved : sepals oblong or elliptic. 3. Y. tenuistyla. 

 Leaves rigid, stiffly spreading : sepals oval or oval-ovate. 4. Y. constricta. 



Style turgid, green. 



Flowers in racemes or almost sessile panicles. 



Leaves rigid, stiffly spreading. 5. Y. glauca. 



Leaves pliable, erect or laxly spreading. 6. Y. Arkansana. 



Flowers in long-stalked panicles. 7. Y. Louisianensis. 



Leaf-blades with markedly horny rough-serrulate yellow or brown margins. 8. Y. rupicola. 



Fruit a drooping pulpy indehiscent berry-like capsule, or erect in Y. recurvifolia. 

 Seeds thin, slightly margined : endosperm not ruminated. 



Leaves rigid, stiffly erect or spreading: capsule 6-ribbed : seeds lustrous. 9. Y. gloriosa. 



Leaves pliable, recurving : capsule 6-winged : seeds dull. 10. Y. recurvifolia. 



Seeds turgid, essentially marginless : endosperm ruminated. 



Ovary stalked : fruit with a purple pulp and coreless : leaves horny and den- 



ticulate on the border. 11. Y. aloifolia. 



Ovary sessile : fruit with a greenish or yellowish pulp and a papery core : 



leaves more or less filiferous. 12. Y. Treculeana. 



1. Yucca filamentosa L. Caudex short : leaves firm, 3-6 dm. long, stiffly erect or 

 spreading, mostly over 2-5 cm. wide, constricted above the base, abruptly acute or some- 

 times rather attenuate, the marginal fibers relatively coarse and curly : flowering stalk 

 1.5-4 m. tall : panicle-branches usually glabrous : perianth white or cream-colored : sepals 

 and petals 4-5 cm. long : capsules 5-6 cm. long, the carpels even in ripening : seeds lus- 

 trous, about 7 mm. long. 



In dry or sandy soil, North Carolina to Florida and Mississippi. Spring and summer. 



2. Yucca flaccida Haw. Similar to Y. filamentosa in habit, but less rigid. Leaves elon- 

 gated, 1-4 cm. wide, long-attenuate, pliable, the outer ones recurved, all with long straight 

 marginal fibers : panicle-branches pubescent : sepals and petals relatively broad : capsules 

 6-7 cm. long, the carpels irregularly flattened in patches while ripening, constricted near 

 the middle at maturity : seeds dull, 8-10 mm. long. 



On dry or stony slopes, in and near the mountains, North Carolina to Alabama. Spring and 

 summer. 



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