r.RITTSII FOREST TREES 327 



three to six years. For a rotation of four years the 

 pollards should stand about seven and a-half feet apart, as 

 experience has shown that such distance yields the greatest 

 outturn of shoots per acre. Harvesting of poll shoots 

 should be undertaken during the latter part of winter or 

 very early in spring, the cut being made as smooth and 

 close to the poll as possible. 



Of the smaller varieties cultivated in osier-beds, the true 

 osier (S. viminahs) is the most important, being characterized 

 by the toughness and flexibility of its thin withes, which 

 grow in thick clusters ; the laurel osier (S. friandra) yields 

 a plentiful crop of long, flexible twigs ; the purple osier 

 (S. purf*urca\ so called from the colour of its anthers 

 during the time of flowering, produces very thin but 

 exceedingly tough withes, principally used for basket- 

 making. So far as the various species can be determined 

 by their leaves alone, the following short descriptions may 

 be of use : 



.V. viminalis Leaves very long, with white, close-lying hairs having 

 a silky gloss. Stipules small, temporary or fugacious, shorter 

 than the petiole, or altogether wanting. 



.V. friandra Leaves quite, smooth, finely serrate. 



.V. purpurea Leaves often opposite, smooth, bluish-green, lanceo- 

 late, finely serrate towards the apex and becoming somewhat 

 broader ; without stipules. 



riodical inundations stimulate the growth of osiers; 

 floods in winter do no harm even if lasting for weeks, but 

 any lengthened submersion during summer is injurious to 

 the crop. Mounds must be thrown up on soils that are too 

 low-lying and wet, whilst stagnant water must be brought 

 into circulation by digging trenches or ditches. Most 

 osier-beds show a mixture of species, the ruling kind 

 depending to a great extent on the nature of the soil and 

 situation, and, as the willows lu\e a very great tendency to 



