116 FLORA OF WASHINGTON AND VICINITY. 



Salix alba, L. White Willow. 

 Last of April or first of May. 



tSalix alba, L., var. I'itelUria, Koch. 

 Last of April or first of May. 



Saliz Bahylonica, L. Weeping Willow. 

 April. 



Salix longifolia, Mulil. Long-leaved Willow. 

 Flats near Chain Bridge. 



tSalix humilis, Marshall. Fraikie Willow. 

 Middle of April. 



Salix tristis, Ait. Dwarf Gray Willow. 

 Last half of March to middle of April. 



Salix sericea, Marshall. Silky Willow. 

 April. 



t Salix cordata, Mvihl. Heart-leaved Willow. 



Eastern Branch Marsh and generally along the Potomac; plants nearly all pis- 

 tillate, often not fertile, hut hybridizing freely with S. sericea. The only staminate 

 plant thus far found was nearly opposite Alexandria. 

 Second or third week in April. 



Salix cordata X sericea, Bchb. \_S. jni/rlcoides, Mnhl! -.S'. cordata, var. myricoxdes, 

 Darl. Flora Cestrica, ed. 3, p. 278, not of Carey, Auderssou, and others.] 

 Piney Branch. 



Salix purpurea, L. Purple Willow. 



Eastern Branch Marsh ; planted to protect drainage embankments. Staminate 

 plants only seen. Second week in April. 



Populus grandidentata, Michx. Large-toothed Aspen. 



Terra Cotta. Male trees only ; doubtless originally planted; spreading considera- 

 bly by subterranean rootstocks. Fully out March '21, 1880. 



Popiilus monilifera, Ait. Cottonwood. Necklace Poplar. 



Only three mature trees of this species are known within our limits. Of these 

 one is male and two are females. One of the female trees, however, is ([uite small and 

 has been pushed down by the ice until it is nearly horizontal, but is alive and appar- 

 ently thrifty. The other two are large, fine trees. The male tree is located near 

 the river, at the water's edge, oi)posite the third lock, a mile above High Island. The 

 large female tree stands at the southern end of High Island. The small female tree 

 is between this and the canal, and is doubtless the offspring of the other two. There 

 is one other smaller offshoot, standing a short distance from the large female tree, and 

 many more such saplings (swept away several years ago by ice and floods) once 

 grew on the flats in the vicinity of Chain Bridge, probably of the same parentage. 

 The peculiarity, however, which justifies this note is, that while the branches of the 

 male tree are not at all angled and those of the large female are onlj' slightly, yet 

 manifestly so, those of the small female and of all the other young siiecimens ob- 

 served are so to a remarkable degree. Unless there be some other means of account- 

 ing for the origin of these young trees than that above pointed out, the case must 

 be regarded as affording a demonstration of the identity of this species with the 

 P. angulaia of Alton. Ai)ril. 



