28 SELECTED ARTICLES. 
Names of Plants. Organs. Dimensions. 
uuiropna 7/ianinoi y 
KOOt, 
3-V 
Hordeum vulgare, 
Seed, > 
Perisperm, 5 
1 
Barley, 
4 
Zea mats, 
do.) 
Maize, 
do. S 
40- 
Orchis latifolia, 
Tubercles. 
1 
Iff 
Salep. 
ART. V.— ON THE DIFFERENT COLORING MATTERS OF 
LEAVES AND FRUITS. — By Berzelius. 
1. The yellow color of leaves in Autumn. 
The change which takes place in the green foliage of trees 
previous to its fall, after an exposure to some nights of frost, is 
well known to be from a green to a fine orange yellow. This 
is observed especially in the Betula alba, the Pyrus malus, 
the Ulmus carnpestris, the Fraxinus excelsior, &c. The 
foliage of the Betula alnus, on the contrary, rarely becomes 
yellow, but falls while yet green; that of the oak does not 
become yellow, but brown. The foliage that has become yel- 
low, sooner or later assumes this brown color, when it be- 
comes dried after its fall. Different researches have been 
already made upon the yellow color of foliage. Macaire 
Prinsephas published the results of several experiments upon 
the autumnal color of leaves — his conclusion is, that the foliage 
in autumn ceases to disengage oxygen, but that it absorbs 
this gas from the air; there is then formed an acid which co- 
lors the foliage at first yellow and afterwards of a red color, 
and, that by neutralizing this acid by means of an alkali, the 
green color of the leaves may be restored; he considers these 
colors, as Clamort Marquart does, to be modifications of one 
and the same coloring matter, which he calls chromule. He 
states that this is the cause of the ordinary yellow or red 
