MYKioPHYLLUM. HALORAGEiE. 219 



less or with a narrow wing or raised border on the upper margin. Oregon 

 to Colorado and the Eastern States. 



C. Bolitnderi Hegelm. Verhandl. Bot. Verein Brandenb. x, 116. Stems 

 stout, elongated, floating : leaves rhombic-oboVate, the submerged ones 

 linear: stigmas twice as long aa the fruit persistent or sub-persistent : 

 fruit orbicular or slightly obcordate, with obtuse closely approximate mar- 

 gins, the lobes scarcely winged. Brit Columbia to California. 



* * Submersed perennials with numerous unifornj 1-nerved leaves : 

 flowers without bracts : carpels separated nearly to the axis. 



C. antnnmalis L. 1. c. Stems very slender, 2-10 inches long: leaves 

 linear truncate or retuse at the apex : fruit sessile, round, deeply notched, 

 nearly a line in diameter, the margins thin or at length winged : stigma 

 long, reflexed, caducous. Eastern Oregon to California, the Eastern 

 JStates, Europe and Asia. 



3 MYEIOPHYLLTJM L. Gen. n. 10, 66. 



Aquatic usually submersed perennial plants, the upper part 

 emersed while flowering, with verticillate, sometimes opposite or 

 alternate leaves, the submersed ones pinnately parted with cap- 

 illary or filiform segments, and sessile flowers in the axils of the 

 upper leaves (which are frequently reduced to bracts) bibracteo- 

 late the uppermost usually staminate, the lower fertile the in- 

 termediate often perfect. Flowers monoecious or frequently 

 perfect. Calyx 4-parted in the sterile flowers, 4-toothed 

 in the pistillate and perfect ones. Petals 4, frequently incon- 

 spicuous br wanting. Stamens 4 or 8. Ovary_4-celled : stigm&,s 

 oblong or linear, often compressed, penicillate, or papillose along 

 the inner surface, recurved. Fruit of 4 indehiscent nut-like 

 carpels cohering by their inner angles and enclosed-in the ad- 

 herent tube of the calyx, apiculate with the base of the stigma. 



* btamens 8, petals caducous carpels not ridged on the back:' 

 leaves verticillate 



M. spicatum L. Sp. 992. Stems very long and slender, branching: 

 leaves ternately verticillate. submerged all pinnately parted with capillary 

 segments, emersed leaves bract-like, shorter than the flowers, ovate, entire, 

 the lowermost larjjer and serrate : bracteoles triangular-ovate, about half 

 the length of the bracts: lobes of the calyx somewhat obtuse: petals 

 broadly ovate : anthers oblong : stigma short, pubescent along the inner 

 side: carpels smooth and even. Deep ponda, Washington to California 

 and the Eastern States. 



M. verticillatuiii L. Sp. 992. Stem stout: lea,ves ternately verticil- 

 late, the lower ones pinnately parted with capillary or setaceous seg- 

 ments, floral leaves pectinate-pinnatifid, commonly much longer than the 

 flowers : bracteoles minute: lobes of the calyx nearly lanceolate, acute, 

 minutely serrulate : petals oblong-obovate : anthers oblong, stigmas 

 linear-oblong, at length woolly : carpels smooth and even. Oregon, 

 Nuttall (not since reported) and the Eastern tftates. 



* * wtamens 3: petals somewhat persistent: carpels 1-2 ridged on 

 the back. 



M. hippuroides Nntt. T & G Fl. i, 530 Leaves quaternately verticil- 

 late, the lower ones pinnately parted, with capillary segments ; floral leaves 

 linear, remotely denticulate or serrate ; petals obovate, carpels nearly 2- 

 ridged on the back. In ponds, Washington to northern California. 



