LEAVES 19 
from which spring smaller lateral roots, and bears on its 
branches net-neined leaves. 
By comparing and contrasting the seeds of these two 
types, points of resemblance as well as of difference will 
be noticed. A description of these seeds has already been 
given. 
V.—SPINES, THORNS, AND PRICKLES. 
Stem-spines. Examine a Hawthorn shoot ; itis covered 
at intervals with sharp pointed woody outgrowths called 
thorns. Many of these stand in the axils of leaves, and 
themselves bear small leaves. But we have learnt that a 
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Fig. 19.—Stem spine of Fig. 20.—Stem spine springing 
Hawthorn, bearing leaf. from axil of leaf. 
branch always has its origin in a leaf-axil—moreover, that 
leaves are always borne by branches—hence we conclude 
that these thorns represent stems or branches, modified to 
act as a protection for the plant. 
Leaf-spines. The leaves of the Holly and the Thistle 
have hard spinose outgrowths which are clearly portions of 
the blade or leaf-spines. 
