CERATOPIIYLLACEAE 89 



10. SPERGULA L. 



Flowers cymose. Stamens 5-10. Styles 5 and capsule 5-valved. 

 1. S. aivensis L. Spurry. 6'-18' high : leaves filiform, V-2' long : 

 flowers white. — Earely occurs along railroads at Sheffield. July-August. 



11. ANVCHIA Michx. Forked Chickwebd. 

 Much branched annuals bearing minute flowers in the forks of the 

 leaves. Sepals 5. Petals none. Stamens 2-5. Stigmas 2. Fruit a 1- 

 seeded utricle. 



Stems puberulent. 1. A. dicholoma. 



Stems glabrous. 2. A . Canadensis. 



1. A. dichotoma Michx. Puberulent and spreading, S'-IO' high, 

 with internodes 2"-i" long : leaves lanceolate-elliptic, numerous. — 

 In dry woods throughout the southern part. — Common locally. June- 

 August. 



2. A. Canadensis (L. ) B.S.P. Nearly glabrous, erect, W-Vi' high: 

 internodes often 12''' long : leaves oval-elliptic. — Common in dry woods. 

 June-August. 



Family 45. NYMPHAEACBAE DC. 

 Aquatic herbs with long horizontal roofstooks and solitary axillary 

 flowers. Sepals 3-5. Petals 5-many. Stamens 5-many. Pistils 3-many, 

 distinct or united. Ovules 1-many. 



1. NBLUMBO Adans. 



Sepals 4-5. Petals and stamens very numerous. Pistils many, each 

 I'Ovuled and inserted separately in pits in the large fleshy obcouical re- 

 ceptacle. 



1. N. lutea (Willd. ) Pers. Chinquapin Water Lily. Leaves cen- 

 trally peltate, raised high out of the water or floating, orbicular, strongly 

 ribbed, l°-2° broad : flowers yellow, i'-Vi' broad. — Very abundant in 

 ponds at Lake City ; also in Fish Lake near Sibley. July-September. 



Family 46. CERATOPHYLLACEAE A. Gray. 

 Aquaticherbswithverticillate leaves, and sessile axillary monoecious 

 flowers. Calyx 8-12-cleft. Sterile flowers with 8-20 stamens with large 

 sessile anthers. Ovary superior, 1-celled, with one pendulous ovule. 

 Fruit indehiscent, beaked with the long persistent style. 



1. CBRATOPHYLLTJM L. 



Characters of the family. 



1. C. demersum L. Hobnwoet. Leaves filiform, verticillate, forked: 

 fruit smooth or tubercled, 2"-%" long. — Common In ponds at Sibley and 

 ShefiBeld. June-July. 



