288 ESSENTIALS OF BOTANY 
(®) The circle of sheathing leaves at each node. Are the leaves 
entirely separate from one another? Split a stem lengthwise through 
a node and examine it with the magnifying glass. 
(c) The cone at the summit of each stem, composed of spore- 
bearing scales. Examine ‘these scales with the magnifying glass to 
determine their shape. Draw the fertile stem. 
III. Study the sterile stems, noting: 
(a) The position, arrangement, and number of the branches. 
(6) The form of the branches and their resemblances to and 
differences from the stem. Draw part of a sterile stem and a 
slightly magnified branch. 
369. Minute Structure.— Cut thin sections of a fertile and a 
young sterile shoot between the nodes.!. Mount in water and ex- 
amine with lp. and m.p. Note: 
(a) The general shape of the section. 
(b) The external grooves and ridges. 
(c) The stomata. 
(d) The position of the portions of tissue containing chlorophyll. 
Is it present in both kinds of stem? 
(e) The fibro-vascular bundles. 
(f) The air-passages, one in the center and two other sets sur- 
rounding it. Draw. 
370. The Spore-Leaves. — Using fresh or preserved material, pick 
off a few spore-leaves from one of the cones. Put them in water in 
the cavity of a slide with concave center. Examine with the mag. 
nifying glass, or, if convenient, with a two-inch objective. Note: 
(a) The stalk of the spore-leaf. 
(b) The number and mode of attachment of the sporangia, or 
cases in which the spores are produced. Draw. 
Tease apart some sporangia in water, mount, and examine with 
m.p. Note: 
(c) The spores, with attached bands known as elaters. Mount in 
water some fresh spores or those that have been merely dried, ex- 
amine without a cover-glass, and note the movements of the elaters 
as the water evaporates. Draw. 
1 Sections of the mature sterile stems are difficult to cut. Prepared slides 
of these and (for comparison) of one of the large perennial-stemmed species, 
as Equisetum hiemale, may be bought of dealers in microscopical material. 
