260 Proceedings of Indiana Academy of Science 



advance — only the hardiest ones being able to gain a foothold and sur- 

 vive. Even many of these will be seen to start to grow for a time and 

 then die, since some of the conditions in the new territory are too ad- 

 verse to allow them to continue growth. After a time other individuals 

 survive the soil conditions and reach maturity, at first probably not 

 producing quite as vigorous specimens as those growing on distant 

 territory. 



It is interesting to see how soon the various forms of plant life 

 will gain and become thoroughly established in the new territory. Some 

 forms begin to grow in a short time, others only after a considerable 

 period of time and some are later crowded out by the stronger forms 

 in the general struggle to survive. 



One plant that could not be overcome by the other species in the 

 area to be discussed was the common Ipomoea piirpia-ea. This plant, al- 

 though it had no support at first, was heavily crowded by stronger 

 forms which appeared after it had grown to a considerable size. Despite 

 this hindrance it grew rather vigorously and almost as large, on the 

 average, as other specimens in the open and under favorable conditions. 

 It was interesting to compare on the other hand, a number of small and 

 somewhat delicate forms, such as Lobelia spicata, which were crowded 

 out. Other rather small and delicate forms persisted and completed 

 their growth before the stronger forms came on. 



The piece of ground to be considei'ed was an area of 200 square 

 feet. It was composed of heavy and rather damp clay and before this 

 experiment began, was covered by a dense growth, mostly of Poa prcu- 

 tensis. It slopes gently to the east but more strongly to the south ex- 

 cept for an artificial swale about the center of the tract. The ground 

 to the west and north of the area is rich soil and heavily overgrown 

 with Poa pratensis. In the directions just mentioned the grass was kept 

 closely cut and free of all weeds to a distance of 75 to 100 feet. The 

 same is true of the east and south although here less space intervened. 



After a time it was noticed that some patches of Rumex acetosella 

 put in their appearance, the seed having been introduced, in all proba- 

 bility with hay which had been strewn rather densely over the ground 

 some time before these observations. This troublesome weed requires 

 the application of quick and drastic methods if it is to be eradicated. 

 The surest and one of the best ways to destroy Rumex acetosella is by 

 the use of common salt, as experiment has sometimes shown. It is often 

 necessary by this method, to sacrifice the surrounding vegetation, but 

 however much it may be desired to spare other plants in the direct vi- 

 cinity, it is generally time and money saved in the end to use salt in 

 abundance and to leave everything else out of the consideration but the 

 destruction of the Rumex acetosella. This plant has a tendency to grow 

 in patches, due to its underground habit, and therefore it lends itself 

 .somewhat more readily to the above mentioned treatment than if grow- 

 ing more scattered. The Rumex acetosella was present on the ground 

 here under consideration and was given two heavy treatments with 

 common salt. This completely and permanently destroyed every vestige 

 of these plants. A light application of the salt is very likely not to kill 



