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THE IMPORTANCE of amphibious species of Polybut did not indicate the percentage of germination. gonum as food and cover for water-fowl and fish is Crocker (1907) reported that within a ten-day test generally recognized by wild life biologists. To period he obtained 85 per cent germination from these workers a knowledge of the behavior of the seed of P. amphibium whose "coats" had been rupseeds is important when propagating these species. tured but no germination from seed with entire Some amphibious species are considered to be weeds "coats." Muenscher (1936) stored achenes of two under certain conditions and a knowledge of the be-lots of P. amphibium dry and in water at both room havior of their seeds is essential when they are to temperatures and 2°C. After approximately two, be controlled or eradicated. Various workers have five and seven months of storage, germihation tests reported conflicting results from laboratory ger-were made. The only germination obtained in these mination tests and field plantings with seeds of am-tests was 26 per cent from achenes stored in water phibious species of Polygonum (Crocker, 1907; at 2°C. for seven months. Achenes which had been Fischer, 1907;Muenscher, 1936;Justice, 1941). stored under these four storage conditions for fi~e In a previous study the author (Justice, 1941) months were cut to remove a portion of the peri-(a) observed considerable variation in the response carp from each; none of the seeds germinated when of different lots of seed of a given species of Polyexposed to germinating conditions. Justice (1941) gonum, (b) obtained low percentages of germina-stored achenes of P. amphibium under the four stortion in most tests in which seeds of the amphibious age conditions used by Muenscher and tested these species were used, and (c) failed to confirm con-for germination over a period of three years. The sistently the higher germination results by subse-results obtained from two lots agreed rather closely quent testing. For these reasons the investigation with those reported by Muenscher. One lot germihas been continued with seeds of Polygonum amnated better than the other two lots but the results phibium, P. coccineum and P. hydropiperoides. A were not consistent. In one test of sixty achenes few data reported herein have been taken from the from this lot, 73 per cent germination was obtained previous paper by permission of the Director of the after storage at 2°C. in water for seven months, but Cornell University Agricultural Experiment Stasimilar results were not obtained in subsequent tion.tests. Seed of all lots were dormant at maturity and These three species flourish and reproduce under none germinated until they had been subjected to amphibious conditions. It has been shown by several low temperatures either in water or between a moist investigators that seeds of some lots of these species stratifying medium for several months. are dormant or exhibit delayed germination at ma-Martin and Uhler (1939) recommended that turity. In Polygonum the fruit is an ach...

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