MORPHOLOGY OF THE SEEDLING - $l 
Transfer the plants to moist blotting paper under a bell-glass or 
an inverted battery jar and examine the roots at the end of twenty- 
four hours to see along what portions their length has increased ; 
continue observations on them for several days. 
’ 42. Root-Hairs. — Barley, oats, wheat, red clover, or 
buckwheat seeds soaked and then sprouted on moist 
blotting paper afford convenient material for studying 
root-hairs. 'The seeds may be kept covered with a watch- 
glass or a clock-glass while sprouting. After they have 
begun to germinate well, care must be taken not to 
have them kept in too moist an atmosphere, or very few 
root-hairs will be formed. Examine with the magni- 
fying glass those parts of the root which have these 
appendages. 
Try to find out whether all the portions of the root are 
equally covered with hairs and, if not, where they are 
most abundant. (See also Sect. 53.) 
The root-hairs in plants growing under ordinary condi-- 
tions are surrounded by the moist soil and wrap them- 
selves around microscopical particles of earth (Fig. 11). 
Thus they are able rapidly to absorb through their thin 
walls the soil-water, with whatever mineral substances it 
has dissolved in it. 
43. The Young Stem.— The hypocotyl, or portion of 
the stem which lies below the cotyledons, is the earliest 
formed portion of the stem. Sometimes this lengthens but 
little; often, however, as the student knows from his own 
observations, the hypocotyl lengthens enough to raise the 
cotyledons well above ground, as in Fig. 10. 
The later portions of the stem are considered to be 
divided into successive nodes, — places at which a leaf (or 
