FAMILIES OF PLANTS 
31 
POND WEED FAMILY (NAIDACEAE) 
Water plants found either floating or immersed in ponds and 
streams. The flowers are inconspicuous and not often seen. The 
following ten species of the genus Potamogeton have been identified 
in the park: P. alpinm , P. filiformis , P. heterophyllm , P. lonchites , 
P. ohtusifoliusj P. peotinatm , P. praelongus , P. natans , P. perfolia- 
tus , and P. robbinsii , Wigeongrass (Ruppia pectinata ), another 
member of the family, has also been reported in the park. 
Figure 13.—Dwarf juniper. Copyright, J. E. Haynes. 
ARROW GRASS FAMILY (JUNGAGINACEAE) 
The plants of this family grow in wet places and remind one of 
plantain. They have rushlike, fleshy leaves which are all basal and a 
spike of greenish flowers. TrigloeMn palustris , which varies from 
5 to 15 inches high, is frequently seen in the park. 
Trigloohin maritima , a somewhat larger plant, has also been 
reported. 
