Tin-: willows of oiiio. 271 



28. Leaves distantly serrate with incurved teeth, not 



revolute. 5. discolor. 



28. Leaves entire or very obscurely serrate, frequently 

 revolute. 29. 



29. Margin undulate-re volute, veins very prominent below, 

 bright green, only rarely completely glabrous. S.humilis. 



29. Margin not undulate, veins not raised below, purplish 

 green. 30. 



30. Leaves elliptical, widest near the middle; dwarf shrub 



in bogs. S. pedicellai 



30. Leaves oblanceolate, widest above the middle; good- 

 sized shrub; often planted. S. purpurea. 

 81. Leaves with a strong marginal vein, smaller veins forming 

 a very line meshwork, leaves -mall, narrow, often fal- 

 cate; tree with pendent branch vlonica. 



31. Marginal if present not extending much below the middle 



of the leaf. :;l\ 



:;_'. Leaves bluntly and coarsely or irregularly serrate with 



incurved teeth or entire; shrubs. 33. 

 32. Leaves sharply serrate with projecting teeth, 36. 

 33. Leaves extremely glaucous below, glossy above, broadly 

 lanceolate orovate; northern. 5. glaucophylla. 



:;:!. Leaves with a thin bloom beneath, not glossy. 34. 



34. Leaves lanceolate, Ion-- acute, venation regular; bark 

 of branches green, smooth ; arborescenl His. 



34. Leaves mostly broadest above the middle, short acute; 

 Lark of branches brown, soon roughened. 35. 



I 5. glaut ophylla. 

 35. Water shoots . blackening in dryin and 



[ 5. discolor. 



35. Well developed leaves, remaining green. S. discolo 



36. L held up by the stiff midril display their 



white' under surfaces, broadly lan< 



mostl y above and very heavily glaucous 



low; northern. s : . 'hylht. 



36. not held up againsl the twigs, mostly lanc< 



late. 37. 



37. Primarii tlyforl id archi irawling shrubs. 



37. Primarii ,1 forki 



looping; arbon rawlinj >. hi 

 39. 



38. I. dull above, no1 t alwa 



with a trace ol hair on the veins above or bel< 



M" ' petiole touti h. xta. 



