466 MINNESOTA BOTANICAL STUDIES. 



erect to ci - eeping and rooting at the nodes ; aquatic or in low 



wet ground, or terrestrial Sec. FLAMMULA. 



C. Blades of stem leaves amplexicaul, leaves entire; flowers 



white 75 . amplexicaulis. 



CC. Blades of stem leaves not amplexicaul ; flowers yellow. 

 D. Stamens numerous. 



E. Plant low or erect, not spreading by slender creeping 

 stems. 



F. Habitat aquatic 76. Lambertianus. 



FF. Habitat terrestrial. 



G. Sepals and petals persistent 77. arnoglossus. 



GG. Sepals and petals deciduous. 



H. Claw of petal i line long 78- unguiculatus. 



HH. Claw of petal not nearly so long. 



I. Akenes beaked. 



J. Stems 2 to 3 feet high, often rooting at lower 



nodes 79- ambigens. 



JJ. Stems much lower, not rooting at nodes. 

 K. Mature fruit glabi'ous. 



L. Beak as long as the akene body. 



So. Madrensis. 



LL. Beak much shorter than akene body. 

 M. Petals 4 to 6 lines long ; plants soli- 

 tary, not much tufted..8i. alismcefolius. 

 MM. Petals about 3 lines long; plants 

 often tufted or covering the ground. 



82. alismellits. 

 KK. Mature fruit villous-pubescent. 



83. Lemmoni. 



II. Akenes beakless ; styles deciduous. 



84. oblongifolius. 



EE. Plant spreading by slender, or fistulous creeping stems. 

 F. Lower leaves sometimes cordate ; flower stems ascend- 

 ing. 



G. Margins of some of the leaves slightly denticulate. 



85. hydrochar aides. 



GG. Margins of leaves entire 86. samolifolius. 



FF. Lower leaves never cordate. 



G. Petals no longer than- the sepals 87. stolonifer. 



GG. Petals nearly twice the length of the sepals. 

 H. Number of petals 8 to 10; plant glabrous. 



88. vagans. 



HH. Number of petals 4 to 8; plants never entirely 

 glabrous. 



