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filzig according to the assumed definition, varied somewhat 

 from the regular types. Examples are Brachyglottis 

 repanda Forst. and Leucophaea canadensis where the ana- 

 tomy of the hair differs from that of the classes given. 

 Pyrethrum balsamita Willd., Eurybia argyrophylla Cass., 

 Artemisia absinthium L. and maritima L. form a little 

 class by themselves in respect to anatomical structure; 

 the stem consists of a cell row of from two to five cells, 

 the filz is formed by a long cell attached to the upper 

 stem cell nearly at its center and lying horizontally 

 across the leaf surface. These upper cells appear to be 

 lifeless and easily separate from the stem when the leaf 

 is placed in water. In Eurybia the stems vary in length, 

 so as to make several layers of long cells, forming a 

 thick filz. These upper cells often contain air, others are 

 empty, all are thinwalled. The filz of these leaves being 

 less permanent than in most cases, they are not included 

 among those considered as typical. 



By glancing through the list it is seen at once, 

 that the greater number of these plants originate from 

 countries where vegetation is obliged to protect itself from 

 drouth. Only seven out of the whole number are said 

 to flourish in moist soil, four of these prefer a moist soil 

 to a dry. Before passing to the consideration of special 

 cases, a few words in regard to the peculiarity of stomata 

 already several times referred to, and which is a constant 

 characteristic of the leaves under consideration. 



The important office of the stomata in general, has 

 given rise to an extended and exhaustive study of their 

 mechanism and its adaptability to the various climatic 



