346 PRACTICAL COURSE IN BOTANY 
sketch, labeling the primary branches of the frond, pinne 
(sing., pinna), the secondary ones, if any, pinnules, and the 
common stalk that supports them, stipe. Note the color, 
texture, and surface of the stipe. If any appendages are 
present, such as hairs, chaff, or scales (in Pteris, nectar 
glands), notice whether they are equally distributed. If not, 
where are they most abundant ? 
Examine the mode of attachment of the stipes to their 
underground axis. Break one away and examine the scar. 
Compare with your drawings of leaf scars and with Fig. 
105. Do the stipes grow from a root or a rhizome? How 
do you know? Do you find any remains of leafstalks of 
previous years? How does the rootstock increase in 
length? Measure some of the internodes; how much did 
it increase each year? Cut a cross section and look for 
the ends of the fibrovascular bundles. Trace their course 
through several internodes. Do they run straight, or do 
they turn or bend in any way at the nodes? If so, where 
do they go? Do you see anything like roots? Where do 
they originate? Put one of them under the microscope and 
find out whether they are roots or hairs. 
True roots are first developed in the pteridophytes. Since 
those of the fern spring from an underground stem, to what 
class of roots do they belong? (88.) 
403. Minute study of a fern stem.— Place a very thin 
section of a fern rhizoma, or of the stipe of a frond, under 
the microscope. Except in very young stems the vascular 
bundles are arranged in a ring, or sometimes in two or 
more rings (Fig. 492), with plates of strengthening tissue, 
1, l, between the inner and outer rings. Notice the inner 
epidermal layer of hard brown tissue, and within that, the 
soft parenchyma, which fills the rest of the interior. Test 
it with iodine and observe how rich in starch it is. If the 
section of a petiole is under observation, the details will 
be somewhat different; would you expect to find as much 
starch in the stipe as in the rootstock? Why, or why not? 
