110 CLASS V. ORDER II. 



AscLEPiAS QUADRiFOLiA. Four Icaved Asclepias. 



Stem erect, simple, smooth ; leaves ovate, acumi- 

 nate, petioled, the middle ones in fours ; umbels few, 

 lax, filiform. 



A delicate species growing in dry woods. Stem about a foot 

 high, smooth, or slightly pubescent. Leaves in fours, slightly 

 petioled, ovate, acute, paler underneath. The upper and lower 

 ones are most frequently opposite. Umbels few, axillary and 

 terminal. Petals flesh colored. Nectaries nearly white with 

 the horns curved inward. — Roxbury, Brookline. — June. — Pe- 

 rennial. 

 Asclepias veuticillata. L. Whorled Asclepias. 



Leaves revolute, linear, whorled ; stem erect. L. 



This very neat species is altogether different in its habit from 

 those already described. Stem slender, marked with downy 

 stripes. Leaves in whorls of five or six, linear, revolute at the 

 margin, paler beneath. Umbels several, small, coming out from 

 among the upper whorls. Corolla greenish with a central trans- 

 parent line. Nectaries white, scarcely half as long as their 

 horns, auriculated at base inside, concavely truncate, with an 

 acuminate tooth each side the fissure within. Horns arching 

 and meeting at a distance from the stigma. — On a hill near the 

 Dedham turnpike, Roxbury.— July.— Perennial. 



^ Subgenus Acerates. Horn of the nectary wanting. 

 Asclepias viridiflora. Pursh. Green Jlower-ed Asclepias. 



Stem simple, erect, hairy ; leaves oblong, subses- 

 sile, downy on both sides; ttmbels lateral, solitary, 

 subsessile, nodding, dense and globose; horn wanting. 



An inelegant species with small greenish umbels. — In Leices- 

 ter, Massachusetts. — In New Haven, Dr. Ives. — July. 



116. GENTIANA. 



Gentiana saponaria. L. Soapwort Gentian. 



Stem round ; leaves lanceolate-oval, three nerved ; 



