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This same form of stoma is characteristic of all the 

 leaves described as filzig except, it may be, two, Tussi- 

 lago and Petasites ; in the latter even of these one sees 

 a tendency toward this form. This is also the ease with 

 leaves whose epidermal surface is protected by the so- 

 called scaly hairs or scales, where no real filz occurs. 

 For example the leaf of Elaeagnus salicifolius Schlecht. 

 Here the scales of the hairs often fit into each other, 

 forming* a close roof-like covering, very seldom is any 

 portion of the leaf-surface left uncovered, and the sto- 

 mata stand quite high. The star-shaped hairs of Deutzia 

 scabra Thunb. on the contrary, are far apart, so that 

 the surface is only dotted and not covered, here the sto- 

 mata stand on a level with the other epidermal cells. 

 This same contrast is seen between those leaves described 

 as filzig and those whose surfaces are thickly covered 

 with hair, but always in such a manner as to leave a 

 free communication between the stomata and the outside 

 air. Quite a number of leaves of this latter class were 

 axamined and in all cases the stomata were either on a 

 level with the epidermal cells, or sunken a trifle below. 

 Such are Glaucium luteum Scop., Androsace lanuginosa, 

 Cephalaria cretacea, Convolvulus cneorum L. 



These examples are perhaps sufficient to establish the 

 fact here insisted upon, namely: Whenever the hairs or 

 scales form a covering so that a protected layer of air 

 exists between this covering and the epidermis, the sto- 

 mata are raised, and where the outside air has free com- 

 munication with the stomata they are not raised. 



It is hardly necessary to add here, that there exists 

 in nature no such clear sharp lines of distinction between 

 filzig and not filzig leaves, raised or level stomata as the 



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