. The life of inland waters; an elementary text book of fresh-water biology for American students. Freshwater biology. 152 Aquatic Organisms In this area there are recorded as growing without cultivation 1278 species. Of these 392 grow in the water. However, fewer than forty species grow wholly submerged, with ten or a dozen additional submerged except for floating leaves. Hardly more than an eighth, therefore, of the so- called "aquatics" are truly aquatic in mode of life: the remaining seven-eighths grow on shores and in springs, in swamps and bogs, in ditches, pools, etc., where o
. The life of inland waters; an elementary text book of fresh-water biology for American students. Freshwater biology. 152 Aquatic Organisms In this area there are recorded as growing without cultivation 1278 species. Of these 392 grow in the water. However, fewer than forty species grow wholly submerged, with ten or a dozen additional submerged except for floating leaves. Hardly more than an eighth, therefore, of the so- called "aquatics" are truly aquatic in mode of life: the remaining seven-eighths grow on shores and in springs, in swamps and bogs, in ditches, pools, etc., where only their roots are constantly wet. The aquatic seed plants are representa- tive of a few small and scattered families. In- deed, the only genus having any consider- able number of truly aquatic species is the naiad genus Potamo- geton. Other genera of river-weeds, or true pond weeds, are small scattered and highly diversified. They bear . many earmarks of independent adaptation to the special situations m the water which they severally occupy. In the economy of nature the Potamogetons or river weeds constitute the most important single group of sub- merged seed plants. They are rooted to the bottom m most shoal waters, and compose the greater part of. Fig. 63. The ruffled pond-weed; Pota- mogeton crispus, one of the most orna- mental of fresh water Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Needham, James G. (James George), 1868-1956; Lloyd, John Thomas, 1884- joint author. Ithaca,N. Y. , The Comstock Publishing Company
Size: 1284px × 1946px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectfreshwa, bookyear1915
