190 MYSTERIES OF THE FLOWERS 



Turk's-cap cactus, brought from the Mexican bor- 

 der by Major Foulois of the U. S. A. Flying Corps, 

 will show the reader how invulnerable a plant may 

 make itself. 



Just as defenceless civilians may take refuge 

 among an armed band of soldiery, so do defenceless 

 plants seek safety among their thorny and prickly 

 kindred, and we find thickets and hedgerows made 

 up of a tangled mass of hawthorns, brambles, and 

 wild roses, interspersed with every kind of soft and 

 tender plant and climbing vine. But there are 

 defences less conspicuous than thorns, yet no less 

 potent. Plants like hardback, ironweed and ver- 

 vain build up woody fibre which makes them in- 

 edible, and strike deep roots to hold them against 

 removal. The laurel has the woody fibre, and also 

 distils poisonous juices into its leaves as an addi- 

 tional protection. The Equisetum stores up parti- 

 cles of silica in its tissues, and hence becomes quite 

 indigestible. 



Then, to ward off the smaller pests which creep 

 and crawl, the plants clothe themselves in hairy 

 raiment, or besmear their stems with sticky cos- 

 metics till ants and beetles, slugs and caterpillars, 

 are held at bay. Water is a sure barrier against 

 such enemies, as some plants seem to know. There 

 are plants which, when growing on land, have rough 



