292 IXIACEAE 



late flowers with a persistent perianth. Ovary inferior : styles 3 : stigmas entire. Ovules 

 2 or rarely one in each cavity, pendulous, anatropous or amphitropous. Capsule broadly 

 3-winged, opening through the wings. Seeds flat, membranous-winged. 



1. Dioscorea villosa L. B-ootstocks knotted, 1-3 cm. thick : stems twining, 1-5 m. 

 long, more or less branched : leaves sometimes whorled below ; blades thinnish, ovate or 

 oblong-ovate, 6-15 cm. long, acuminate, entire, bright green above, pale and somewhat 

 pubescent beneath, cordate, usually 9-11-nerved ; petioles slender, as long as the blades or 

 shorter : staminate flowers 3 mm. broad, whitish, in delicate panicles : sepals and petals 

 ovate or oblong ; tube very short : pistillate flowers in simple racemes : hypanthium early 

 elongated: capsules 1.5-2.5 cm. long, broadly 3-winged, persistent, becoming lustrous and 

 dry at maturity : seeds 1-2 in each cavity, broadly thin-winged. 



In thickets, Ontario to Rhode Island and Minnesota, Florida and Texas. Summer. YAM. WILD 

 YAM-BOOT. 



FAMILY 3. IXIACEAE Ecklon. IRIS FAMILY. 



Perennial, moptly caulescent herbs, with bulb-like or elongated rootstocks. 

 Leaves equitant, 2-ranked, commonly elongated. Flowers perfect, regular or 

 irregular, solitary or in clusters from spathe-like bracts. Perianth often highly 

 colored : sepals and petals nearly equal or often very different, withering-per- 

 sistent or fugacious, distinct, or united below. Androecium of 3 stamens, adnate 

 to the perianth opposite the sepals. Filaments filiform, distinct or partially 

 united. Anthers 2-celled, extrorse. Gynoecium of 3 united carpels. Ovary 

 inferior, 3-celled. Styles distinct, entire or parted, sometimes petal-like. Ovules 

 numerous, anatropous, on central placentae. Fruit a loculicidally 3-valved cap- 

 sule. Seeds numerous in 1 or 2 rows in each cavity. Embryo straight in the 

 fleshy or horny endosperm. [Iridaceae Lindl.] 



Styles alternate with the stamens. 



Styles 2-cleft or 2-parted. 1. NEMASTYLIS. 



Styles entire or stigmas merely emarginate. 



Rootstocks bulb-like. 2. CALYDOREA. 



Rootstocks not bulb-like, often elongated. 



Filaments distinct : seeds drupe-like. 3. GEMMINGIA. 



Filaments wholly or partially united : seeds dry. 4. SISYRINCHIUM. 



Styles opposite or arching over the stamens. 



Styles slender : filaments united into a tube. 5. HERBERTIA. 



Styles petal-like : filaments distinct. 6. IRIS. 



1. NEMASTYLIS Nutt. 



Caulescent herbs, with coated bulb-like rootstocks. Stems terete. Leaves alternate : 

 blades narrow, elongated, folded. Flowers solitary or several together from two herbaceous 

 bracts, fugacious. Perianth usually showy : lobes 6, nearly equal. Stamens 3 : filaments 

 more or less united. Ovary 3-celled : styles alternate with the stamens, each parted into 

 2 filiform segments : stigmas terminal. Ovules numerous. Capsule somewhat elongated, 

 loculicidally 3-valved at the apex. 



Leaves or some of them overtopping the inflorescence : perianth-lobes broadest below the middle. 



1. N. acuta. 

 Leaves not overtopping the inflorescence : perianth-lobes broadest above the middle. 2. N. coelestina. 



1. Nemastylis acuta (Bart.) Herb. Foliage bright green. Stems 1-6 dm. tall, 

 simple or sparingly forked : leaf -blades linear, 1-3.5 dm. long, some at least overtopping 

 the inflorescence : flowers 2-3 from a spathe : bracts unequal, the outer shorter : perianth 

 light blue or purple, 4-5 cm. broad ; lobes slightly unequal, broadest below the middle : 

 capsule turbinate or obovoid-turbinate, 10-15 mm. high. 



On prairies, Tennessee to Kansas, Louisiana and Texas. Spring. 



2. Nemastylis coelestina (Bart. ) Nutt. Foliage deep green. Stems 3-6 dm. tall, 

 somewhat zigzag : leaf -blades linear, 1-4 dm. long, or more reduced above, none overtop- 

 ping the inflorescence : flowers commonly solitary in the spathes : bracts lanceolate or 

 linear-lanceolate, the outer shorter : perianth bright blue, about 4 cm. broad ; lobes nearly 

 equal, broadest above the middle: capsule oblong-prismatic, 2-2.5 cm. long, obtusely 

 3-angled. 



On prairies or in pine woods, Georgia to Florida and Texas. Spring and summer. 



2. CALYDOREA Herb. 



Caulescent herbs, with coated bulb-like rootstocks. Leaves mainly basal : blades nar- 

 row, sometimes nearly filiform. Flowers usually few from the terminal solitary spathe. 



