POLYPETALOUS EXOGENOUS PLANTS. 145 



tt Petals much larger than the calyx ; achenia in globose heads. 



R REPENS, L. Smooth or hairy ; leaves ternate, or the 

 earliest ones 3-lobed; leaflets 3-lobed, tootlied; achenia 

 strongly margined, pointed with the broad and straight or 

 slightly curved beak ; sterns erect or prostrate, often bear- 

 ing long runners. Eich soil. Varieties to be found in 

 river swamps. March, April. 



K. BULBOSUS. Hairy ; stem erect (1°-1 J° high) from a 

 bulbous base. Radical leaves petioled, 3-parted, and some- 

 what pinnately divided ; leaflets 3-cleft, incisely toothed ; 

 those of the upper leaves lanceolate, entire. Floivers large 

 (1' wide) ; achenia pointed with a short recurved beak. 

 Low grounds. May. 



CALTHA. Marsh Marigold. 



Calyx colored, of 5-9 sepals, resembling petals ; corolla 

 wanting ; stamens indefinite, shorter than the sepals ; fol- 

 licles 5-10, capitate or whorled, sessile, spreading, many- 

 seeded. Aquatic, and very glabrous. 



ISOPYRUM, L. False Rue, Anemone. 



Sepals 5-6, regular, ovate, colored, imbricated in the bud, 

 deciduous. Petals 5, small, tubular, sometimes wanting. 

 Stamens numerous. Ovaries 2-20. Style short, subulate. 

 Follicles subsessile, acuminate with the style, membrana- 

 ceous, 2-several-seeded. Delicate herbs, perennial, smooth. 

 Leaves compound, alternate. Floivers pedunculate, axil- 

 lary and terminal, white. — Torr. and Gr. 



I. biternatum. Stem, (6'-12' high) slender, sparingly 

 branched; radical leaves biternate, on long petioles ; stem- 

 leaves ternate, nearly sessile; leaflets ovate and obovate, ob- 

 tusely 3-lobed ; petals none ; ovaries 1-5 ; follicle 2-seeded. 

 Shady woods. April. — Torr. and Gr. 



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