





76 FLOWERING PLANTS 
layer of woolly hairs, so that the leaf seems almost wrapped in 
flannel. The same contrivance is found in shore plants which 
are exposed to burning suns, and have the same difficulty as 
alpine plants in getting a regular supply of water. An example 
of this is the Hairy Hawkweed (Mieracium pilosella), so widely 
distributed on the shores of the Mediterranean, and common 
inEngland. The leaves of this Hawkweed are radical, and form 
a rosette, clasping the soil; they are green on the upper side 
and white on the under, owing to the star-shaped hairs, which 
: form a thick felt 
ae eeag ag on its - suriace. 
When the ground 
gets very dry the 
leaves turn up, 
the whole leaf 
becomes _ rolled ; 
the under side is 
then turned to- 
wards the sun’s 
rays, and _ pro- 
tected by the 
hairs. One of the 
most conspicuous 
of hairy plants in 
Fig. 44.—SEcTION THROUGH LEAF-BLADE OF Kngland is the 
MULLEIN, SHOWING Harrs. Mullein. It is im- 
| possible here to 
mention all the different kinds of hairs; their variety is im- 
mense, and those interested in the subject may consult Kerner 
(vol.1., pp. 314-325), wheresome beautifulillustrations are given. 
Structure of Lhe leaves of Water-Plants are classified by 
Hydrophytic Willis (‘Flowering Plants and Ferns,” vol. i., 
web p. 171) as follows: 7 
1. The ribbon type, as in Vallisneria. 
2. The much-divided type—e.g., submerged leaves of the 
Water Crowfoot. 
3. The awl-shaped type in submerged leaves, as in Isoetes 
and others able also to live on dry land, 


