AQUATIC PLANTS OF FRESHWATER 



or Chilian Water-milfoil, Fig. 1 1 6. The pectinate-pinnatifid submerged 

 and emersed leaves are alike and 

 grow in whorls of 4's and 5's about 

 a creeping stem. The minute 

 white auxiliary and pistillate flowers 

 have 4 stamens and develop 4 car- 

 pels. Small hairlilce white bracts 

 are borne at the base of the leaves 

 and among the flowers. The finely 

 pinnate, brilliantly green leaves and 

 their graceful habit in growing 

 above the water has made this a 

 very desirable plant, but it is an 

 indifferent oxygenator, as the sub- 

 merged leaves soon slough off and 

 the rapidly growing plant sends its 

 green crown of leaves 4 to 6 inches 



° FIG. no. PuiTot s father, Myriopiy Hum froserpwa- 



above the surface of the water. cades. Emersed leaves. Reduced one-fourth. 



The emersed leaves fold together at 

 sundown to again open after sunrise. 

 It is a beautiful semi-aquatic plant, and 

 is extensively grown in watertight hang- 

 ing baskets or jars where the fine single 

 stems hang over the sides in handsome 

 festoons. 



In addition to the above described 

 form there are two species of true 

 Proserpinaca found in the United States, 

 viz, P. palustris and P. fectinata, gener- 

 ally distributed in the Southern States. 



Proserpinaca palustris (Linn.) or 

 Common Mermaid-weed, Fig. 117, is 

 not an indigenous plant but is now 

 native to swamps from New Brunswick 

 to Lake Huron and south to Florida, 

 Iowa, Cuba and Central America. It 

 is an aquatic herb with single stem apd 

 alternate dentate leaves about a weak 

 stem. The perfect flowers are stigmatic 

 above the middle with 3 or 4 styles, 

 and the bony fruit has one seed in each 



FIG. 117. Mtinaii-vcei^ Proserpinaca 

 palustris. Reduced one-third. 



191 



