LEMNACEAE 73 



4. SPATHYEMA Raf. 



1. Spathyema foetida(L. ) Raf. Skunk Cabbage. (Mau. p. 231; 

 I. F.y. 88/.) In swamps, N. S. to Minn., Fla. and Iowa. — Pentisylvania : 

 Huntingdon; Lancaster; Northampton; Frankun ; Chester; 

 Delaware ; Allegheny. 



5. ORONTIUM L. 

 1. Orontium aquaticum L. Golden Club. (Man. p. 231 ; I. F. y. 

 S82.) In swamps and ponds, Mass. to Pa., Fla. and La., mostly near the 

 coast. — Pennsylvania : Northampton ; Monroe ; Lancaster ; Cum- 

 berland ; Chester ; Huntingdon ; Delaware ; Lackawanna ; Som- 

 erset ; Pike. 



6. ACORUS L 



1. Acorus Calamus L. Sweet Flag. C.\lamus-root. (Man. p. 

 231 ; I. V.f. SSj.) In wet places, N. S. to Minn., La. and Kans. Also in 

 Eu. and Asia. — Pennsylvania : Northampton; Philadelphia, Point 

 Breeze ; Monroe ; Franklin ; Delaware ; Columbia ; Alegheny. 



Family 2. LEMNA.CEA.E Dumort. Duckweed F'amily. 



Plant-body much elongated or subglobose, not disk-like, rootless : propagative 



pouches solitary. i. Wolffia. 



Plant-body disk-like, with i or several roots : propagative pouches 2. 



Plant-body inconspicuously nerved : roots solitarj* on each plant, without a 



fibro-vascular bundle. 2. Lemna. 



Plant-body conspicuously nerved : roots several, each with a fibro-vascular 

 bundle. 3. Spirodei.a. 



1. WOLFFIA Horkel. 



Plant-body smooth, somewhat flattened above, gibbous beneath, abundantly 

 brown-punctate. i. Jf. ptinclata. 



Plant-body ellipsoidal or globose, with 2-3 papules on dorsal surface, not 

 punctate. 2. ]\\ Columbiana. 



1. Wolffia pmictata Griseb. Punctate Wolffia. (Man. p. 234. ) 

 On the surface of stagnant waters, east of the Mississippi River from the 

 Lake region to the Gulf of Mexico — Pennsylvania : According to Britton, 

 Man. p. 234. 



2. Wolffia Columbiana Karst. Columbia Wolffia. (Man. p. 233; 

 I. F. /. Sgo.) Floating on water, Ont. toN. J., Minn, and Mo., Mex. and 

 S. Am. — Pennsylvania : Phil-'VDELPHIa ; Bucks. 



2. LEMNA L. 



Plant-bodies long-stipitate, forming large submerged masses, i. L. Irisulca. 

 Plant-bodies sessile or short-stipitate, floating, more or less detached. 



Plant-body symmetrical or nearly so. 2. L. minor. 



Plant-body unsymmetrical. 3. L. perpusilla. 



1. Lemna trisulca L. Ivy-leaved Duckweed. (Man. p. 232 ; I. F. 

 f. 88^.) In still or flowing water, N. S. to Pacific coast, N. J. and N. 

 Mex., also in Eu., Asia, Africa and Australia. — Pennsyli'afiia : Lan- 

 caster ; Northampton ; Mercer ; Chester. 



