180 



PRACTICAL BOTANY. 



Boiling the leaves in Schultze's macerating mixture serves 

 the same purpose. Also draw, under high power, a few 

 cells from the wide base portion of the leaf. Have you 



found stomata ? Exam- 

 ine pieces of the epider- 

 mis torn from the stem 

 for stomata. Do you 

 find them ? Stomata 

 are sometimes found 

 on the midribs of the 

 leaves and on the setae. 

 Under low power 

 draw one of the leaves 

 or bracts from an an- 

 theridial head. Draw 

 a few cells of the bract 

 as seen under high 

 power. 



Examine under low 

 power cross sections of 

 the leaf. The sections 

 are best cut from pieces 

 of the upper, leafy 

 portion of the stem 

 imbedded in celloidin. 

 Some of the sections of 

 the leaves will be nearly 

 or quite transverse. Locate the axial bundle of the mid- 

 rib. Notice the lamellae on the upper surface. Draw the 

 entire section. Also draw some of the lamellas as seen 

 under high power. 



4. If material gathered in the spring can be studied, 

 dissect a male head in water and try to make out, using 

 both low and high powers, the antheridia somewhat 

 thick, ovoidal bodies made up of polygonal cells and 



FIG. 105. A, antheridia and filiform and 

 spatulate paraphyses of Polytrichum 

 commune ; B., C, and I), antherozoids of 

 same in their cysts, and variously mag- 

 nified. (After Thuret.) 



