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THE BOOK OF NATURE STUDY 



tubular construction, while quite rigid, economises the material 

 needed in the growth of the shoot. Two leaves are borne at 

 each node, and stand immediately opposite to one another. The 

 pair of leaves alternates in position with the pairs immediately 

 above or below. This arrangement avoids the shadowing of 

 the leaves of one pair by those borne at the succeeding node. 

 The stem is green or purplish in colour, and is sparsely covered 



with white hairs. Each foliage-leaf con- 

 sists of a slightly widened leaf-base, 

 a well-marked leaf-stalk, and a simple 

 leaf-blade ; there are no stipules. The 

 leaf-stalk is grooved above and rounded 

 below, and its margins bear long soft 

 hairs. The blade widens out suddenly 

 at the upper end of the leaf-stalk, and 

 just above this attains its greatest 

 breadth, from which it gradually narrows 

 to the tip. Its margin is cut into 

 teeth, which point like the teeth of a 

 saw to the tip. The blade is traversed 

 by a midrib, and it, as well as the main 

 branches which form a beautiful net- 

 work, project on the paler lower surface. 

 While buds which may give rise to 

 small lateral shoots are found in the 

 axils of some of the lower leaves, all the 



FIG. 71. Plant of the white upper pairs of leaves have clusters of 



flowers in their axils. The flowers are 

 so closely crowded that they appear to 

 completely surround the stem at the 



node. They are, however, in two groups in relation to the two 

 leaves. The cluster of flowers lowest on the shoot begins to 

 open first, and is succeeded by the group at the next node, 

 and so on. The flowers of any one axillary group also do not 

 open simultaneously. The first to open is the flower standing 

 immediately over the leaf-base ; this is followed by one to either 

 side, and these by buds standing laterally to them. All these 

 flowers after the first one stand in the axils of minute, pointed 



R 



Dead-nettle. R, roots ; I, 

 internode ; N, node ; F, 

 flower. (After Farmer.) 



