SALICACEAE. 



11 



SALIX. Willow. 

 (Family Salicaceae). 



Shrubs or trees: deciduous. 

 Bark at first usually smooth and 

 green, gray and more or less fis- 

 sured in age. Wood soft, white 

 becoming brown, minutely dif- 

 fused-porous with fine medullary 

 rays, satiny when split. Twigs 

 mostly slender, terete: pith rather 

 small, roundish, continuous, white. 

 Buds mostly small, oblong, ap- 

 pressed, sessile, solitary, with a 

 single exposed scale standing im- 

 mediately over the leaf-scar, or 

 collaterally multiple, the end-bud 

 absent. Leaf-scars alternate or 

 exceptionally opposite, low, U- 

 shaped: bundle-traces 3: stipule- 

 scars short, often absent. 



Willows are particularly diffi- 

 cult to name at any time of the 

 year by characters which may be 



put in words, but the comparatively few species that enter 

 into landscape use to any considerable extent usually differ 

 in habit, color of bark, etc., characters which one gardener 

 points out to another. 



They illustrate particularly well a type of elongation in 

 which each season's growth is made by the development of an 

 axillary bud of the preceding year, the end of the twig dying 

 back in winter, as it commonly does in Salix, or falling early 

 in the season by a clean-cut abscission-scar, as in Ulmus, Tilia 

 and many other trees, where the scar is small and often pushed 

 to one side so as to be likely to be overlooked, and in Ailan- 

 ihus, where it is particularly large and evident. 



