In the next group of the musiceae, or mosses, is an absence of some
chemical compounds that were characteristic of the classes just
described. Many of the albuminous substances are present. Starch[14]
is found often in large quantities, and also oily fats, which are
contained in the oil bodies of the liverworts; wax,[15] organic acids,
including aconitic acid, and tannin, which is found for the first time
at this evolutionary stage of the plant kingdom.
The vascular cryptogams are especially characterized by their mineral
composition.[16] The ash is extraordinarily rich in silicic acid and
alumina.
Equisetum[17]..........silicic acid 60 per cent.
Aspidium............... " " 13
Asplenium.............. " " 35
Osmunda................ " " 53
Lycopodium[18]......... " " 14
" ........ alumina 26 to 27
" ........ manganese 2 to 2.5
These various plants contain acids and compounds peculiar to
themselves.
As we ascend in the plant scale, we reach the phanerogams. These
plants are characterized by the production of true seeds, and many
chemical compounds not found in lower plants.
It will be convenient in speaking of these higher groups to follow M.
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