and Laboratory Methods. 2617 



in large quantities and kept in a dry glass bottle. Rhizomes with fertile and 

 sterile branches should be preserved in 70 per cent, alcohol. Good herbarium 

 specimens may also be used. 



Sporophyte. 



1. Sketch a plant containing the rhizome, fertile shoot with cone, and young 

 sterile shoot. Note the whorls of scale-like leaves at the nodes; also the lack 

 of chlorophyll in the fertile shoot. 



2. Sketch a mature sterile shoot. 



3. Note and describe the division of labor in the stem of this plant— rhi- 

 zome for a food storehouse and for vegetative propagation, fertile branch for the 

 production of nonsexual spores, sterile branch with abundant chlorophyll for 

 food manufacture. From whence is the material obtained which goes to form 

 the fertile shoot ? 



4. Cut off some of the peltate sporophylls, mount and draw from the side 

 under dissecting microscope. Show the stalk, the angular outer expansion and 

 the sack-like sporangia hanging from the under side. How are the sporophylls 

 arranged in the cone ? Compare this cone and the sporophylls with those of 

 Lycopodimn ohscunim. 



5. Place a small flake of the dry spores on a slide without water or cover- 

 glass, breath on them gently until the glass becomes moist, and examine imme- 

 diately under low power. Note the spores with appendages coiled about them. 

 In a few moments the spores will be in violent agitation, while the appendages 

 uncoil. Breath gently on the slide while looking into the microscope. How 

 many appendages on each spore ? Draw. Describe in detail the hygroscopic 

 properties of the appendages. Of what advantage to the plant is this peculiar 

 arrangement ? 



G. Cut cross sections of a young fertile branch from alcoholic material. 

 Mount, stain with iodin solution and draw under low power. Note the epider- 

 mis, the wide cortical layer with a circle of lysigenous cavities, the endodermis, 

 the circle of vascular bundles, and the pith with a large central lysigenous cavity. 

 The xylem (wood) of each vascular bundle is arranged somewhat in the form of 

 a V, the apex of the Y being occupied by a large air-cavity. The two limbs of 

 the V end near the endodermis, and the phloem is situated between these two 

 masses of xylem. 



(b) Eijnisefiim hyemale L. Scouring Rush. 



This plant grows in wet places along the banks of rivers, creeks and 

 lakes. 



1. Examine the fresh or dry stems under low power. Notice the parallel 

 grooves and ridges, with lines of tubercles and stomata. Draw and describe. 



2. Break some of the dry stems and note their brittleness. Burn one of 

 the stems in a hot tlame, mount the outer part of the shell which remains, and 

 examine under low power. Notice that the cell walls and stomata are still dis- 

 tinct. This is because the cell walls are impregnated with silica. Draw a flake 

 showing the stomata. 



