HALORAGIDACEAE. 251 



Family 73. HALORAGIDACEAE. Water- 

 milfoil Family. 

 Perennial or rarely annual herbs, mainly aquatic, 

 with alternate or verticillate leaves, the submerged ones 

 often pectinate-pinnatifid. Flowers perfect or monoe- 

 cious or dioecious, axillary in interrupted spikes, solitary 

 or clustered. Calyx-tube adnate to the ovary, its limb 

 entire or 2-4-lobed. Petals small, 2-4 or none. Sta- 

 mens 1-8. Ovary ovoid-oblong or short-cylindric, 

 2-8-ribbed or winged, 1-4-celled; styles 1-4; stigmas 

 papillose or plumose. Fruit a nutlet or drupe, com- 

 pressed, angular, ribbed or winged, indehiscent, of 2-4 

 1-seeded carpels. Endosperm fleshy; cotyledons minute. 



Ovary 1-celled. 1. Hippuris. 



Ovary 4-celled. 2. Myriophyllum. 



1. HIPPURIS L. 



Aquatic herbs with simple erect stems and verticillate 

 entire leaves. Flowers small, axillary, perfect or some- 

 times neutral or pistillate. Limb of the calyx minute, 

 entire. Petals none. Stamens 1, inserted on the margin 

 of the calyx. Style filiform, stigmatic its whole length, 

 ying in a groove of the anther. Fruit a small 1-celled, 

 1-seeded drupe. 



1. H. vulgaris L. Stem slender, glabrous, 2-5 dm. high; leaves 

 linear or lanceolate, acute, sessile, 1-20 mm. long, in crowded 

 verticils of 6-12; stamens with a short thick filament and com- 

 paratively large 2-celled anthers, dehiscent by lateral slits; seeds 

 ovoid; stigma persistent. 



Not known within our limits, but occurring in the San Bernardino 

 Mountains. 



2. MYRIOPHYLLUM L. 



Aquatic herbs with verticillate or alternate leaves, the 

 emersed ones entire, dentate or pectinate, the submerged 

 ones pinnatifid into capillary segments. Flowers axil- 

 lary, often interrupted-spicate, commonly monoecious, 

 2-bracted. The upper flowers generally staminate with 

 very short calyx-tube, the limb of this 2-4-lobed or 

 wanting; petals 2-4; stamens 4-8. Intermediate flowers 

 often perfect. The lower pistillate, the calyx more or 



