82 KEY AND FLORA 



32. NYMPHJEACE^a;. Water Lily Family 



Perennial aquatic herbs. Leaves usually floating, often shield- 

 shaped. Flowers borne on naked scapes. Floral envelopes and 

 stamens all hypogynous or epigynous. Sepals 3-6. Petals 

 3-6 or often very numerous. Stamens many. Carpels 3 or 

 more, free or united. Fruit a berry or a group of separate 

 carpels. 



I. WYMPHiEA L. 



Rootstock horizontal, thick, cylindrical. Leaves heart-shaped, 

 floating or erect. Flowers yellow. Sepals 4-6, green on the 

 outside, obovate, concave. Petals many, hypogynous, the 

 inner ones becoming small and stamen-like. Stamens many, 

 hypogynous. Ovary cylindrical, many-celled ; stigma disk- 

 shaped. Fruit ovoid.* 



1. N. advena Ait. Yellow Pond Lily, Cow Lily, Spatter- 

 Dock. Leaves oval or orbicular, rather thick, often downy beneath. 

 Flowers bright yellow, '2-?i in. in diameter, depressed-globular. 

 Sepals C>. Petals thick and fleshy, truncate. Stamens in several 

 rows ; anthers nearly as long as the filaments. In slow streams and 

 still water.* 



II. CASTALIA Salisb. 



Eootstock horizontal, creeping extensively. Leaves float- 

 ing, entire) shield-shaped or heart-shaped. Flowers showy. 

 Sepals 4, green without, white within. Petals many, white, 

 becoming smaller towards the center. Stamens many, the 

 outer with broad and the inner with linear filaments. Ovary 

 many-celled, stigmas shield-shaped and radiating. Fruit berry- 

 like, many-seeded.* 



1. C. odorata WoodviUe and ■\'\'ood. White Water Lily. Root- 

 stock large, branched but little. Leaves floating, entire, the notch 

 narrow and basal lobes acute, green and smooth above, purple and 

 downy beneath. Petioles and peduncles slender. Flowers white, very 

 fragrant, opening in the morning, S-5 in. broad. Fruit globose ; seeds 

 inclosed in a membranaceous sac. In ponds and still water.* 



2. C. tuberosa Greene. Much like No. 1 . Rootstock bearing loosely 

 attached, often compound tubers. Leaves round-kidney-shaped, sel- 

 dom purple beneath. Flowers larger than in JSTo. 1, scentless or nearly 

 so. Slow streams, especially W. 



