Beautiful Flowering Shrubs 



condition even before the stamen heads open their trap- 

 door valves. 



What precisely is the mechanism of these sensitive 

 and moving stamens has been a matter for much dis- 

 cussion. The microscope shows that at the sensitive 

 point there is a layer of cells with pits in their walls, 

 so that there can be a rapid interchange of water be- 

 tween them. Thin-walled cells lie over this layer. 

 Normally the contents of the cells are in a thick band 

 on the back wall. Touch the sensitive spot, and this 

 band becomes lax and curves, pulling in the side walls 

 and causing pressure on the outer wall which arches. 

 Therefore all the cells of the layer become shorter and 

 thicker together, and the filament, which is leaning out- 

 wards, is sharply pulled up. Hence the movement 

 responding to the touch. 



A hybrid B. stenophylla a cross between the 

 Darwinian Barberry and a little-known dwarf Chilian 

 Barberry B. empetrifolia is a very desirable shrub. 

 It arose in a nursery garden near Sheffield, in 1860, 

 and inasmuch as it is of more graceful habit than its 

 Darwinian parent, it is sometimes claimed to be " the 

 most beautiful and useful of all the barberries." Its 

 long slender sprays are veritable arches of golden 

 bloom. The leaves are small and very dark green 

 above, white below. Its fruit is a purple berry with a 

 whitish bloom upon it, but the seeds rarely come true. 



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