Page:An introduction to physiological and systematical botany (1st edition).djvu/365

 Rh the above account highly probable in a country where the sun has so much more power, even if it did not come from the most faithful and philosophical botanist of antiquity, and I have always with confidence cited it on his authority. The reader, however, will perceive that the only important circumstance for our purpose is the closing of the flowers at night, which is sufficiently well established.

But the most memorable of aquatic plants is the Valisneria spiralis, well figured and described by Micheli, Nov. Gen. t. 10, which grows at the bottoms of ditches in Italy. In this the fertile flowers stand on long spiral stalks, and these by uncoiling elevate them to the surface of the water, where the calyx expands in the open air. In the mean while plenty of barren flowers are produced on a distinct root, on short straight stalks, from which they rise like little separate white bubbles, suddenly expanding when they reach the surface, and floating about in such abundance as to cover it entirely. Thus their pollen is scattered over the stigmas of the first-mentioned blossoms, whose stalks soon afterwards resume their spiral figure, and the