— 6 — 



terminate in a cup-shaped enlargement sunk into the 

 mesophyll and connected with it by pores. The mem- 

 brane of the hair in the immediate vicinity of this 

 enlargement, is said not only to lack the wax coating 

 which covers the upper part of the hair but also to 

 have a zone where the cuticle entirely fails. The author 

 gives his opinion that this hair is just as truly an organ 

 for absorption as the minute thread-like rootlets which 

 break out suddenly just below the stem of the plant 

 immediately after a rain-fall or heavy dew and then 

 just as suddenly disappear. 



These articles are selected from the numerous recent 

 ones touching the question of water absorption from the 

 air, and it may be said in general that in most of the 

 literature on the subject of Trichomes the function of 

 absorption is usually referred to as a probable one, 

 though always of secondary importance. 



The material used for the following work was ob- 

 tained, in part, from the Botanical garden in Berlin, in 

 part, from that of Zurich. The leaves were examined 

 fresh from the garden or green-house, the time extending 

 from the first of May till the middle of October. About 

 80 specimens were examined which are described as 

 filzig *). By filzig is meant, where the coating is so thick 

 and the hairs are so interwoven or matted together as 

 to form a system of capillary tubes between the inter- 



*) The German words Filz and filzig have been used through- 

 out this work, as they seem to express the meaning more clearly 

 than the English, felt and felt like. The latter are used more 

 with reference to the cloth or tissue as a whole than the German 

 words where the idea of the interweaving of threads, by which 

 process the tissue is made, is retained in the word fdz. 



