193 
CLASS CRYPTOGAMIA. 
presented (Fig. 
155) with a delin- 
eation of three 
kinds of Fuci.* 
a, is Fucus nodo- 
sus, (knobbed fu- 
cus ;) this ^has- 
forked fronds. 
The knobs which 
appear in the 
fronds are air- 
bladders, which 
render it pecu- 
liarly buoyant 
upon the water. This is oftM more than six feet long, b, Fucus ve- 
siculosus, (bladder fucus ;) here the air-bladders are mostly axillary, 
and at the sides of the midrib. It varies in length from one to four 
feet. On account of its mucilaginous property it forms a good ma- 
nure ; in some of the countries of-Lapland it is bailed with meal, and 
given for food to cattle, c, Fucus serratus ; this has a beautiful ser- 
rate frond. 
The Fuci,t on burning, afford an impure soda, called kelp. 
Order J^ickenes, or Lichens. 
The 5th Order contains the Lichens; these are various in texture, 
form, and colour ; they are leathery, woody, leaf-like, white, yellovv\ 
green, and black. When wet, they often appear like green herbage ; 
some are seen on stones, or old fences and buildings ; others with 
strong, green filaments, are suspended from branches of trees, and 
improperly called mosses. The fruit of the Lichen consists of sau- 
cer-like bodies, called apothecia, in which the seeds are contained; 
this may be seen in the following delineation. Fig. 156, a, represents 
to the existence of the Laplander. In the middle af Europe it grows 
only to the height of two or three inches ; but in Lapland it some- 
times attains to the height of one foot and a half. 
Many of the lichens are useful on account of their colouring mat- 
ter. Litmus, which is so common as a chemical test for acids and 
alkalies, is obtained from a species of white lichen, called Orchal, or 
Archil, this is also used for giving a crimson colour to wool and silk. 
The powder called cudbear, used for dying purple, is obtained from 
* See also Appendix, Plate viii. Fig. 8, 9, 10, 11, 
* 1 ''uci is the plural of Fucus. 
a 
a lichen, of a leaf- 
like appearance ; 
here the apothe- 
cia imbedded in 
the leaves are ve- 
ry apparent, b, is 
a lichen resem- 
bling a drinking- 
glass. c, is the 
rein-deer moss, 
furnishing almost 
the sole food of 
that useful ani- 
mal, so important 
Ihree kinds of Fuci— Kelp— Lichens— Explain Fig. 156— Uses of the lichens. 
