(280) 



pie, rarely a divisor. Carpidia united into a 

 single ovary. 



Family 1. HALORRHAGIDEiE. 



Calyx tube adnata to the ovary; limb 4-parted. 

 Petals, if present, alternate with calyx lobes. 

 Stamens not more than twice as man3^ as petals; 

 if of equal number opposite to them. Pla- 

 centa3 central, 1-ovulate. Styles as many 

 as cells. 



1. Hippuris L. Mare's Tail. 



Flowers ^ , or sometimes polygamous, m'o- 

 nandrous; filament subulate. Ovary 1-celled, 

 1-ovulate, style filiform. Fruit a caryopsis. — 21, 

 Aquatic. Leaves verticillate; flowers minute, 

 solitary in the axils. 



1. H. VULGARIS L. — Marine Hospital (at pres- 

 ent extinct). Summer. 



2. Myriophyllum L. Water milfoil. 



Monoecious. $ : petals caducous; stamens 8. 

 ? : calyx limb and petals minute; stigma vil- 

 lous; ovary 4-celled, 4-ovulate. 



1. M. spiCATUM L.— Marine Hospital. 

 Camp Taylor. Summer. 



Family 2. ONAGRACEiE. 



Calyx tube adnate to the ovary. Petals al- 

 ternate with them, not valvate in aestivation. 

 Stamens inserted with petals, as many or a 



