fiALORAGE;E, ONAGRACE^. 49 



ORDER XXXVI. HALORA'GE^I. (WATER-MILFOIL F.) 



Aquatic or marsh plants, with small inconspicuous flowers, 

 sessile in the axils of the leaves or bracts. Calyx-tube ad- 

 herent to the ovary, the latter in one genus 4-lobed and 4- 

 celled ; in the other of a single carpel. Limb of the calyx minute 

 or none. Petals 4, if any. Stamens 1-8. Fruit indehiscent, a 

 single seed in each cell. 



Synopsis of the Genera. 



1. Myriophyl'lvmi. Flowers monoecious or polygamous, with the parts in 



fours. Stamens 4 or 8. Immersed leaves pinnately dissected into 

 capillary divisions. 



2. Hippu'ris. Flowers perfect. Stamen, st3 f le, and carpel only one. Leaves 



entire, linear, acute ; in whorls of 8 or 12. 



1. MYRIOPHYL'LUM, Vaill. WATEK-MlLFOIL. 



1. M. spica'tum, L. Stamens 8. Bracts ovate, entire, shorter 

 than the flowers. Leaves in whorls of 3 or 4. Flowers greenish, 

 in terminal spikes. Stem very long. Deep water, 



2. M. verticil! a'tum, L. Stamens S. Leaves finely dissected 

 and whorled as in No. 1. Bracts pectinate-pinnatifid, much 

 longer than the flowers, and the spike therefore leafy. Stem '2-4 

 feet long. Stagnant water. 



3. M. heterophyllum, Michx. Stamens 4- Lower leaves 

 dissected, in whorls of 4 or 5. Bracts ovate or lanceolate, finely 

 serrate, crowded, the lower ones pinna tifid. Stem stout. Stag- 

 nant or slow water. 



2. HIPPU'RIS, L. MABE'S TAIL. 



H. VTllga'ris, L. A perennial aquatic, with jointed erect stem. 

 Muddy margins of ponds and streams. 



ORDER XXXVII. ONAGRA'CBJE. (EVENING-PRIMROSE F. ) 



Herbs, with perfect and symmetrical flowers, the parts of the 

 latter in twos or fours. Calyx-tube adherent to the ovary, and 

 usually prolonged above it. Petals and stamens inserted on the 

 calyx. Style 1. Stigmas 2 or 4 or capitate. (See Part I, sections 

 41 17, for description of a typical plant.) 



