Page:An introduction to physiological and systematical botany (1st edition).djvu/225

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The œconomy of the Sarracenia, an American genus of which we now know four species, and of the East Indian Nepenthes distillatoria, deserves particular mention. Both grow in bogs, though not absolutely in the water. The former genus has tubular leaves which catch the rain like a funnel and retain it; at least such is the nature of S. purpurea, Curt. Mag. t. 849, whose margin seems dilated expressly for this purpose, while the orifice of the tubular part just below is contracted to restrain evaporation. Linnæus conceived this plant to be allied in constitution to Nymphæa, and consequently to require a more than ordinary supply of water, which its leaves were calculated to catch and to retain, so as to enable it to live without being immersed in a river or pond. But the consideration of some other species renders this hypothesis very doubtful. S. flava, t. 780, and more especially S. adunca, Exot. Bot. t. 53, are so constructed that rain is nearly excluded from the hollow of their leaves, and yet that part contains water, which seems to be secreted by the base of each leaf. What then is the purpose of this unusual contri-