2034 



The Cornell Reading Courses 



species are shown in figure 199. These and the following species are 

 widely distributed throughout the State and can be recommended as 



A B c 



Fig. 200. — -A, spiked water-milfoil; B, hornwort; C, fanwort, or cabomba 



fulfilling admirably the five functions mentioned heretofore : P. pectinatus 

 (fennel-leaved pondweed) ; P. perfoliatus; P. obttisif alius ; P. rohhinsii. 

 P. crispus, P. pectinatus, and P. rohhinsii have green foliage through- 

 out the winter; the others die down in autiunn. P. crispus and P. 

 pectinatus are very prolific and on rich bottom soil will be likely to 

 crowd out nearly all other plants. They should therefore be introduced 

 with caution, and it would be well to put them in a place from which 



they may be easily removed. All 

 these pondweeds, with the possible 

 exception of P. amplifolius, will 

 grow in shallow water; the latter 

 is ordinarily found in water from 

 four to seven feet deep. 



The wild celery, eelgrass, or tape 

 grass (V"a//«5wma spiralis) , is another 

 flat-leaved aquatic, which has some 

 value in the pond, but just how 

 much has not been satisfactorily 

 determined. 



The spiked water-milfoil {Myrio- 



phyllum spicatum) , hornwort (Cerato- 



FiG. 201. — Water crowfoot phyllum demersum), and the white 



water-crowfoot {Ranunculus aquatilis), all with finely divided leaves, 



are of value because they harbor hosts of small food animals and are 



