MICROSCOPE O THE GARDEN. 



41 



glass placed over them on the slide. Hairs are 

 frequently formed of several cells. On the white 

 dead-nettle the hairs are composed of two cells, as 

 seen in figure 79 a. The nucleus, or cytoblast, is 

 often seen in these, and is represented in figures 

 76, 77, and 79, plate 3. On the common groundsel 

 hairs may be seen, composed of several cells, each 

 cell containing a nucleus, as at figure 796. Hairs 

 like a string of beads are found on the pimpernel 

 and sow-thistle, which last will be found m 

 ficrure 80, plate 3. Occasionally haii^ become 

 branched. Thus, on the leaf of the common 

 chrysanthemum the hairs present the form of the 

 letter T. This hair is represented at figure 82, 

 On the under-surface of the leaves of the common 

 hollyhock hairs are seen with several branches, 

 giving them a stellated appearance, as seen at 

 figure 84. The common lavender is covered with 

 st'ellate hairs, as seen at figure 85a. These 

 hairs may be examined as opaque or transparent 

 objects, when immersed in a little glycerine. 

 The hair of the tobacco plant presents a peculiar 

 knobbed appearance. The presence of these hairs 

 is a test of the purity of tobacco. It is shown 

 in fic^ure 81. The verbena has rosette -shaped 

 hairs° as in figure 83. Sometimes hairs are 

 covered over with little dots, which are supposed 

 to be deposited after the growth of the cells of 

 the hair. Such hairs may be seen in the common 

 verbena, and are represented at figure 856. 

 Hairs are sometimes loose and long, as in the 

 white poplar, seen at figure 86. Occasionally an 

 elevation, consisting of several cells, is formed at 

 the base of a hair. These are shown in figure 87. 

 When these cells contain a poisonous secretion, 

 which is transmitted along the tube of the hair, the 

 hair is called a glandular hair, or sting. Such aro 



