'03 
CLASS CRYPTOGABnA. 
presented (Fi^^. 
155) with a delin- 
eation of three 
kinds of Fuci.* 
«, is Fucus nodo- 
sus, (Icnobbed fu- 
cus ;) this has? 
forked fronds. 
The knobswhich 
appear in the 
fronds are air- 
bladders, which 
render it pecu- 
liarly buoyant 
upon the water. This is often more than six feet long. 6, 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 boiled with meal, and 
given for food to cattle, c, Fucus serratus ; this has a beautiful ser- 
rate frond. 
The Fucijt on burning, afford an impure soda, called kelp. 
Order Jvichenes^ or Lichens. 
The 5th Order contains the Lichens; these are various in texture, 
form, and colour ; they are leathery, woody, leaf-like, white, yellow, 
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 
a lichen, of a leaf- 
like appearance ; 
here the apothe- 
cia imbedded in 
the leaves are ve- 
ry apparent. 6, 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 
to the existence of the Laplander. In the middle ^f Europe it grows 
only to the height of tw^o or three inches ; but in j^apland 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 
♦ iee also Appendix, Plate viii. Fig. 8, 9, 10, 11. 
^ 1 'uci is the plural of Fucus. 
1 hree kinds of Fuel— Kelp— Lichens— Explain Fig. 156— Uses of the lichens. 
