16 Class III. Order III. 



The Iris Virginica of Linnaeus, characterized by an ancipital 

 stem and ensiform leaves, is probably identical with this species. 

 IRIS PRISMATICA. Pursh. Boston Iris. 



Iris imberbis ; foliis linearibus ; caule tereti, 

 plurifloro ; germinibus trigonis, lateribus trisulcis. 



Flowers beardless ; leaves linear ; stem round, 

 many flowered ; germs triangular, twice grooved on 

 the sides. 



Syn. IRIS GRACILIS. 1st edit. 

 IRIS VIRGINICA. Torrey. 



This plant was first described by me in the former edition of 

 this work under the name of I. gracilis. Two years afterwards 

 Mr. Pursh gave it the name of I. prismatica, which name I am 

 willing to adopt, the other having 1 since been bestowed on an 

 African plant. When I sent it to the late Dr. Muhlenberg, he 

 at first pronounced it I. Virginica, but afterwards agreed that it 

 was new. Having a round stem and linear leaves, it certainly 

 wants the Linnaean characteristics of I. Virginica. Its best dis- 

 tinctive character is the doubly grooved germ, which Pursh has 

 overlooked. 



Root fleshy, sending out short runners from which new plants 

 arise ; stem round, smooth, slender, from one to two feet high, 

 branching at top, bearing several alternate leave?, and from two 

 to eight flowers. Leaves linear, erect, sheathing at their base. 

 Bractes or involucres close, becoming dry. Peduncles flattened 

 on the inside, varying in their proportions to the bractes, but 

 commonly longer. Outer petals slender, spreading, purple at 

 the edge, yellow and veined in the middle, the yellow portion 

 much greater than in the last species. Inner petals lanceolate, 

 slightly emarginate. Germs oblong, three sided ; sides with 

 two deep parallel grooves, the whole representing a cylinder 

 with three smaller ones attached to its sides. As the germ en- 

 larges, the distance between the two furrows does not increase, 

 and they are nearly obliterated in the capsule, which is trian- 

 gular and turgid with its three rows of seeds. 



Found at South Boston and Cambridge in the same places with 

 Iris Virginica, but much less frequent. June. Perennial. 



