WOOD-SORREL 193 
to push itself straight out. But here the projecting arm 
at right angles gets in the way, for it has probably either 
caught in a crack in the soil, or is blocked by some herb. 
So the pressure tends to force the other end, the seed 
end, away, and this is well suited to move, for it has a 
boring point. When the corkscrew gets dry again it 
finds the seed hard to draw back, because of the barbs 
on it, and the arm has to give way and draw a little 
nearer. Thus in time the seed gets buried, and the curled 
beak above, its duty satisfactorily accomplished, dies away. 
In Chapter V. we talked of the rather different method 
adopted by the Wood-sorrel and Balsam to give their 
seeds a good start, and you may remember that they 
preferred the explosive method, somewhat after the 
fashion of the Squirting Cucumber. As the Wood-sorrel 
is a close relative of the Geraniums and has another 
point of interest, I will describe it here. As its name 
implies, we must look for it in woods and damp, shady 
places, and there we may hope to find the delicate trefoil 
leaf, pleasantly acid to the taste, darker below than above, » 
and in May or June the exquisite 
white flowers, marked with the purple 
veins which guide the insects to the 
honey. If you tap the leaf-stalks, 
you will find that the leaflets promptly 
shut down, as they do every night 
when the sun goes down. Remember 
that a plant has no muscles like ours, 
and this prompt action of the cells 
becomes in view of this astonishing. 
Many suppose this to have been the 
original Shamrock which St. Patrick 
used to illustrate his sermon to the WOOD-SORREL, 
fo) 
