Elatine. ELATINACE^. 91 



ORDEa XVIII. ELATINACEiE. Camhessedes. The Water-wort Tribe. 



Sepals 2-5, mostly distinct, persistent. Petals hypogynous, as many as the 

 sepals and alternate with them. Stamens hypogynous, as many or twice as 

 many as the petals : anthers fixed by the middle, introrse. Styles 2-5, very 

 short, distinct or united at the base, or none : stigmas capitate. Capsule 2-5- 

 celled, 2 — 5-valved : dehiscence septifragal. Seeds few or many, oblong- 

 cylindrical, with little or no albumen. Embryo cylindrical : cotyledons short. 

 — Small annual plants, growing in marshes, with fistulous rooting stems, oppo- 

 site, entire or serrated leaves, and minute axillary flowers. Stipules small and 

 inconspicuous, sometimes wanting. 



1. ELATINE. Linn.; Endl. gen. 5^75. WATER-WORT. 



[ From the Greek, elate, a fir ; its fine leaves bearing some distant resemblance to those of a fir tree.] 



Calyx 2 - 4-parted. Petals 2-4. Stamens 2-8. Capsules 2 - 4-valved ; margin of the 

 valves not introflexed. 



1. Elatine Americana, Arnott. American Water-wort. 



Stem diffuse, with assurgent branches ; leaves cuneate-obovate, obtuse ; flowers sessile, 

 minute ; sepals, petals, stamens and sessile stigmas 2, sometimes 3 ; seeds few (6 - 8). — 

 Am. in Edin. jour. nat. ^ geog. science, 1 . p. 430 ; Torr. ^ Gr. fi. N. Am. 1 . p. 203. 

 Peplis Americana, Pursh, fl. 1. p. 238. Crypta minima, Nutt. in jour. acad. Philad. 1. 

 p. 117. t. 6./. 1 ; Torr.fl. \.p. 32. Elatine minima, Fisch. et Meyer in Linncea, 10. p. 69. 



Stem rooting and creeping, forming patches ; the assurgent branches rising to the height of 

 an inch, or sometimes nearly two inches. Leaves 2-3 lines long, entire. Flowers solitary, 

 about the size of a pin's head. Sepals (always?) 2, oval, obtuse. Petals 2, roundish, con- 

 cave, closely applied to and enclosing the ovary. Stamens 2, alternate with the petals : 

 anthers didymous, lying in close contact with the stigmas. Ovary globose, 3-celled, with 

 4-5 ovules in each cell : stigmas usually 3, distinct, short. Capsule membranaceous, 

 globose, 3-celled (always ?) ; the dissepiments breaking away from the valves, 6 - 8-seeded. 

 Seeds large for the size of the capsule, a little curved, marked with longitudinal lines, and 

 transverse wrinkles with intervening excavations. 



Margins of ponds, Suffolk county, Long Island ; Peach Pond, Westchester county {Dr. 

 Mead). Flowers from July to September. 



12* 



