(18) 



4. Sanguisorba. Perigonium caljcine ; limb 



4-cleft, colored. Stamens inserted on 

 an annular throat (faux). 



5. Negundo. Perigonium very small, 4- 

 dentate. Fruit a 2-seeded samara, Tree. 

 Shrub. 



II. Tetragynia, 



1. Tillasa. Calyx 4-sepalous. Corolla 4- 

 petalous. Follicles 4, each 2-seeded. 



2. Sagina. Calyx 4-sepalous. Corolla 4- 

 petalous. Capsule 4-valved. Seeds ren- 

 iform. 



3. Cuscuta. Corolla gamopetalous, 4-cleft. 

 Ovary 1; ovules few, inserted on the 

 base of the ovary. Oapsule circum- 

 scissile. Parasitic. 



4. Potamogeton. Perigonium 4-parted. 

 Fruit, 4 sessile drupes. Aquatic. 



PENTANDEIA, 

 I, Monogyma, 



A. Floral parts gamopetalous, inferior. 



a. Fruit 4 nutlets, each 1-3 seeded. 



aa. Ovary with 4 sutures finally sepa- 

 rating into 4 nutlets. 



1. Heliotropium. Corolla funnel-shaped, 

 throat naked, limb plicate. 



