134 ONA GRACES. (jTENING-PBIMROSE FAMILY.) 



1. C. liHteHhna, L. Stem mostly pubescent (l=-2° high); leaves ovate, 

 pointed, slightly toothed ; bracts none ; hairs of the roundish 2-celled fruit bristly. 

 — Moist woodlands. July. (Eu.) 



2. C. alplna, L. Low (3' - 8' high), smooth and weak ; leaves heart-shaped, 

 thin, shining, coarsely toothed ; bracts minute; hairs of the obovate-oWong 1-celJed 

 fruit soft and slender. — Cold woods ; common northward. July. (Eu. ) 



Suborder II. HALORAGEiK. The Water-Milfoil Family. 



7. PROSERPINACA, L. Mermaid-weed. 



Calyx-tube 3-sided, the limb 3-parted. Petals none. Stamens 3. Stigmas 

 3, cylindrical. Fruit bony, 3-angled, 3-celled, 3-seeded, nut-like. — Low, peren- 

 nial herbs, with the stems creeping at the base (whence the name, from proserpo, 

 to creep), alternate leaves, and small perfect flowers sessile in the axils, solitary 

 or 3 - 4 together. 



1. P. palustris, L. Leaves lanceolate, sharply serrate, the lower pecti- 

 nate when under water ; fruit sharply angled. — Wet swamps. June - Aug. 



2. P. pectinacca, Lam. Leaves all pectinate, the divisions linear-awl- 

 shaped ; fmit rather obtusely angled. — Sandy swamps, near the coast. 



8. MYRIOPHYIilirM, VaiU. Water-Milfoil. 



Flowers monoecious or polygamous-. Calyx of the sterile flowers 4-parted, of 

 the fertile 4-toothed. Petals 4, or none. Stamens 4-8. Fruit nut-like, 4- 

 celled, deeply 4-lobed: stigmas 4, recurved. — Perennial aquatics. Leaves 

 crowded, often whorled; those under water pinnately parted into capillary 

 divisions. Flowers sessile in the axils of the upper leaves, produced above 

 water; the uppermost staminate. (Name from p-vpios, a tlwusand, and (f)vX\ov, 

 a leaf, i. e. Milfoil.) 



* Stamens 8 : petals deciduous : carpels even : leaves whorled in threes. 



1. M. spicatum, L. Leaves all pinnately parted and capillary, except 

 the floral on&i or bracts; these are oi^ate, entire or toothed, and chief y shorter than 

 the flowers, which thus appear to form an interrupted leafless spike. — Deep 

 water, common. July, Aug. (Eu.) 



2. M. vcrticilliitlini, L. Floral leaves much longer than the flowers, pec- 

 tinate-pinnatifid : otherwise nearly as No. 1. — Ponds, &c. northward. (Eu.) 



* * Stamens 4 : petals rather persistent : carpels 1 - 2-ridged and roughened on the 

 back : leaves whorled in fours and fves, the lower with capillary divisions. 



3. M. heterophyllnm, Michx. Stem stout ; _^orai leaves ovate and 

 lanceolate, thick, crowded, sharply serrate, the lowest pinnatifid ; fruit obscurely 

 roughened. — Lakes and rivers, from N. New York westward and southward. 



4. in. Scabratum, Michx. Stem rather slender ; lower leaves pinnately 

 parted with few capillary divisions ; fm-al leaves linear (rarely scattered), pectinate- 

 toothed or cut-serrate : carpels strongly 2-ridged and roughened on the back. — Shal. 

 low ponds, from Rhode Island and Ohio southwai-d. 



