306 minnesota botanical studies. 



Haptere. 



A longitudinal section of the haptere shows that it is composed 

 of a layer of cuticle on its surface and below this are the pris- 

 matic epidermal cells with their numerous chromatophores. 

 Next to these are two layers of hypodermal cells, and just 

 within are the cells of the cortex. These are much larger and 

 more irregular in form than the epidermal cells {Jig. J). In the 

 center of the haptere are found rather thick walled elongated 

 cells arranged in rows. 



These rows run in a straight course to the apex of the hap- 

 tere (Jig- 4), while cells at the sides of the haptere bend in 

 curving rows from the circumference towards the center ( figs. 

 3, 2.) The cells near the end of each row have the power of 

 dividing and it is here that the haptere increases in length and 

 in thickness. Both cross and longitudinal sections reveal 

 numerous circular openings in the hypodermis. These are the 

 mucilage ducts which in the haptere seems to take the form of 

 spherical pits. Faint traces of branches may sometimes be seen, 

 so that it is possible that these pits are in communication with 

 each other. Each pit is surrounded by little granular secreting 

 cells. 



There is no pith in the haptere, the thick-walled, elongated 

 cells of the cortex occupying the interior of the haptere. 



In the stipe is found much the same arrangement of tissues 

 as in the haptere, but with this difference, that a pith web occu- 

 pies a considerable portion of the interior of the stipe. 



The lower cylindrical portion of the stipe is hollow with only 

 traces of the pith web left. In the upper, younger, more flat- 

 tened portion, the pith web fills the center of the stipe 

 {Jig. 6, A, B). 



The cuticle is thicker on the surface of the stipe than on the 

 haptere ; the epidermal cells are slightly more elongated but 

 otherwise much like those of the haptere {Jig. 9). The hypo- 

 dermal cells consist of several rows and among them are found 

 the mucilage ducts. A cross section shows them to be large 

 elliptical openings, very close together, in fact with only the 

 bounding cells of each duct between. Each duct appears to 

 have been formed as a fissure between four or five adjoining 

 cells {Jig. 8). These cells have very granular contents, are 

 enlarged at the ends of the ducts but compressed where the 

 ducts are broadest. The longitudinal section shows the ducts 



