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IOWA ACADEMY OF SCIENCE Vol. XXIV, 1917 
the hypocotyl. The hypocotyl made a rapid growth, in five days 
it became somewhat woody and was more than twice as long 
as the acorn. Small lateral roots were soon produced. On No- 
vember 14 the longest root measured 28 cm., while the longest 
stem measured 8 cm. The first leaves on the stem were reduced 
to scales, these scales successively increased in size ; both scales 
and leaves were covered with trichomes. The trichomes of the 
stem are long pointed and frequently curved, generally occurr- 
Fig. 60. — 1. Trichomes of white oak from stem. 2. Trichomes of white 
oak from leaf. Drawn by C. M. King. 
ing singly or sometimes in groups of two or three, not strictly 
stellate. Some trichomes woolly, especially on very young stems ; 
the walls colorless, thick, contents brownish. On the green leaves 
trichomes simple, long pointed, thick walled, occasionally in 
clusters of two or three. Trichomes of upper surface similar to 
those on lower. On very young leaves the upper and lower 
surfaces are woolly, trichomes occurring singly or in groups. 
The first fully formed leaf was serrate. In the greenhouse the 
