50 



ORGANOGRAPHY. 



the Wig-tree (Rhus Cotinus) {fig. 119) the flower-stalks become 

 converted into hair-like prolongations, and in many cases, the 



Fig.Wl. Fig.US. 



Fig. 119. 



Fig. 117. Pistil of Bell-flower {Campamda), with its style 

 covered witli collecting hairs Fi<j. 118. Magnified repre- 

 sentation of two of the collecting hairs of the Bell-flower. 

 a. The hair in its normal position, b. The hair with the 

 upper part partially drawn within its lower. From Schleiden. 



Fig.'i'iQ. Flowering branch of the Rhus Cotinus, or ^\ ig-tree, with 



one branch bearing fruit and the others covered with hairs and sterile. 



calyx of the Compositce and allied orders, present a hairy- 

 character. 



2. Glands. — This name properly applies only to cells which 

 secrete a peculiar matter, but it is also vaguely given to some 

 other superficial appendages. Glands have been variously di- 

 vided by different authors: thus by some, into external and 

 internal; by others, into simple and compound; while others 

 again, have adopted different classifications. The simplest ar- 

 rangement, and the one which we shall adopt, is into external 

 and internal glands. 



a. External Glands. — These may be again divided into .s^atterf, 

 and sessile or not stalked. The stalked glands are those which 

 are commonly called glandular hairs. They are formed of a 

 single cell, dilated at its apex by tlie peculiar fluid it secretes 

 (figs. 120 and 121); or of two (fig. 124) or more secreting cells 

 (fig. 125) ]»lac('(l at the end of a hair; or they consist of a mass 

 of socntini; cells (figs. 122 and 123). Sessile glands jiresent 

 various appearances, and consist, like the former, of either 

 one secreting cell (fig. 127), or of two or more (fig. 126). 

 Those with one secreting cell placed above the level of the 

 epidermis are frequently termed papuhv or papilhc. It is to 

 their jtrescnce upon the surface of the ice-jdant that the 

 peculiar crystalline appearance of that plant is due. When 

 sessile glands consist of cells containing soUd secretions so that 



