12 BIRDS OF PENNSYLVANIA. 



Red-heads which were busily engaged in feeding. As the ducks arose 

 from the water I succeeded in killing two of them. Assisted by my 

 honored friend, Benjamin M. Everhart, I made an examination of 

 the stomachs of these two specimens, and found that both had fed ex- 

 clusively on " wild celery,"* a somewhat common, though not abun- 

 dant aquatic plant in this vicinity. 



FOOD. 



Wilson says the Red-head is a common associate of the Canvas- 

 back, frequenting the same places and feeding on the stems of the 

 wild celery. 



Audubon, writing of the Red-heads, states : " I have found their 

 stomachs crammed with young tadpoles and small water-lizards, as 

 well as blades of the grasses growing around the bank. Nay, on sev- 

 eral occasions, I have found pretty large acorns and beech-nuts in 

 their throats, as well as snails, entire or broken, and fragments of the 

 shells of various small unios, together with much gravel." 



I have examined the stomach-contents of twenty-one Red-heads, 

 both sexes, which have been killed during the shooting season at 

 Havre-de-Grace, Maryland, and found only gravel and vegetable 

 matter, the latter consisting mainly of the so-called " wild celery " 

 ( Vallisneria spiralis). 



147. Aythya vallisneria (WiLS.). 



Canvas-Back. 



DESCRIPTION. 



Bill long, slender and tapering ; head all round and neck chestnut ; the top of the 

 head and region around the base of the bill dusky-brown ; rest of neck, body ante- 

 rior to the shoulders, back behind, rump and tail coverts, black ; under parts white ; 

 the region anterior to the anus, the sides, the interscapulars and scapulars, white, 

 finely dotted, in transverse line, with black, the white greatly predominating ; spec- 



* " This plant, like many others, has a variety of local names. Some of the most common 

 which I now call to mind are tape grass, from the tape-like appearance of the long: leaves; 

 channel-weed, as it frequently grows in channels where the water flows, not swiftly ; eel-grass ; 

 this name arises, it is said by Dr. Darlington (Flora Cestrica)* 'from the habit which eels have 

 of hiding under the leaves which are usually procumbently floating under the water's surface. 1 

 The appellation k wild celery 'a local term applied, I think, chiefly by gunners and watermen 

 at Havre-de-Grace and vicinity is, I consider, like many vulgar synonyms, a misnomer, as this 

 plant is in no particular related to celery, which by botanists is known as Apium. * Wild celery,' 

 or as it is more generally known in this vicinity (Chester county, Pa.), as ' eel-grass,' is found in 

 the Brandywine creek growing in slow running water. 



The scientific name of the plant is Vallisneria spiralis (Linn.), the generic name being given in 

 honor of Antonio Vallisneri, an Italian botanist; the specific spiralis is applied in consequence 

 of the fact that the fertile stalk in its development assumes a spiral form. It is a remarkable 

 dioecious, herbaceous plant on account of its mode of fertilization. It grows entirely under 

 water, has long, radical grass-like leaves, from one to three feet long and from one-fourth to 

 three-fourths inches wide. The female flowers float on the surface at the end of long, thread- 

 like spiral scapes, which curiously contract and lengthen with the rise and fall of the water. The 

 male flowers have very short stems or scapes, from which the flowers break off and rise to the 

 surface, to fertilize with their pollen the attached, floating female flowers^" B. M. EverharVs 

 Botanical Publications, November, 1886. 



