THE WILLOWS OF OHIO. 275 



species, especially in winter when it is leafless. In summer the 

 long slender twigs sometimes give it almost the appearance of the 

 Weeping Willow from which, however, it can be easily distin- 

 guished by its leaves green, not glaucous. The winter buds are 

 very small, less than 3 mm. long, broadly ovate, acute, commonly 

 but not always without the mark of the leaf base across the back. 

 The leaves commonly are about 10 cm. long by 1 wide, narrowly 

 lanceolate with a very long attenuate-falcate tip, mostly very 

 finely serrate, green and glabrous on both sides. The character- 

 istic venation of the Amygdalenae is at its fullest development 

 in Salix nigra. The marginal vein often runs almost to the very 

 base and the secondaries and tertiaries blend into a system of 

 meshes finer than in any other of our species. 



Sometimes broad, blunt leaves are found at the bases of 

 lateral twigs but they are still easily recognized by their fine re- 

 ticulation. The aments appear with the leaves, capsules glab- 

 rous, short conic, short pedicelled, forming thin close cylindric 

 catkins which, supported as they are by the characteristic leaves, 

 resemble those of no other species. The staminate resemble 

 very closely those of 5. amygdaloides (which see), stamens 5 or 

 more, filaments pubescent. 



Everywhere throughout the state, Salix nigra is our com- 

 monest willow. But it assumes a much more important role in 

 plant society along the southern border than further north. 

 There it attains its greatest size and at the same time becomes 

 much more abundant than elsewhere. For long distances along 

 the Ohio River it is almost the only native willow met with and 

 occupies all the territory which in the north is divided up between 

 several species. 



So far as Ohio is concerned it is perhaps the most constant 

 and easily recognized of our willows but in the south it is almost 

 identical with 5. humboldtiana and is rather hard to separate 

 from 5. longipes. In the west it is represented by several 

 variable varieties which seem to connect it with related forms 

 and render it a very difficult subject indeed. 



Its typical habitat is along streams but it may be found in 

 wet places generally though it seems to prefer moving to stagnant 

 water and is much more infrequent in swamps. 



The varietv "falcata" is a form with narrower more falcate 

 leaves. In my opinion it is scarcelv worthy of consideration 

 since it is not genetically different but is merely an accidental 

 leaf variation without correlated variation in other characters 



Plate I. Salix nigra. 



Leaves of ordinary growth and of ranker growth with stipules; flowers 

 and fruit typical; natural size; drawings of the flowers and capsule made 

 with camera lucida and photographed, enlarged seven times. 



