272 OHIO STATE ACADEMY OF SCIENCE. 



38. Leaves subglossy, frequently very glaucous, when 

 young sometimes pubescent but with evenly dis- 

 tributed sericeate hairs, inclined to be distantly ser- 

 rate with prominent glands, petiole slender, leaves 

 hanging down gracefully from the twigs. 



5. petiolaris. 



39. Venation mostly regular, reticulations not very fine, no 

 marginal; trees with smooth bark on the branches. 40. 



39, Venation mostly irregular, reticulations very fine, with a 

 strong tendency toward a marginal ; bark of branches 

 ridgey, brown. 41. 



40. Bark of branches yellow to olive; serrations very fine 

 and sharp, not especially glandular. 5. alba. 



40. Bark of branches green; serrations rather distant, 

 glands prominent, glauscescence absent from the 

 veins beneath leaving them contrasted with the 

 rest of the leaf. S. jragilis. 



41. Northern and western parts of state only, shapely tree, 

 especially in swamps; leaves ovate-lanceolate, twigs 

 smooth. S. amy gdalo ides. 



41, Extreme south only, straggling tree or sprawling shrub in 

 river beds; leaves oblong-lanceolate, twigs usually 

 pubescent. 5. longipes. 



AMYGDALENAE, BLACK WILLOWS. 



Mostly trees with rough brown bark, leaves long attenuate, 

 often falcate, with a marginal vein at the tips at least, reticula- 

 tions of the secondaries and tertiaries very fine. Catkins un- 

 folding with the leaves, stamens 5 or more, filaments pubescent, 

 scales one colored, deciduous, capsules glabrous, green, style 

 short or none. Conspicuous inhabitants of the temperate re- 

 gions of America and extending clear through the tropics to Chili 

 and Peru. 



For a key to this section of the genus I feel that I cannot do 

 better than copy the following table in which the characters of 

 the three species are contrasted, from an article by Dr. Glatfelter 

 in Science Nov. 1, 1895, which I have found quite useful. It is 

 constructed for the forms about St. Louis and is particularly 

 servicable on that account ; for Missouri is the only region where 

 the ranges of all three species overlap and all can be studied 

 together. 



