368 proceedings of the indiana academy of science. 

 Weed Seeds in the Soil. 



F. J. PiPAL. 



In spite of the continued fight the farmer is waging against weeds he 

 finds that these tramps of the vegetable kingdom manage to keep his farm 

 well stocked with their seed and are able to produce abundant crops of their 

 kind every season. 



Most weeds produce a great abundance of seed. Single, rather large 

 specimens of crabgrass and foxtail, our two commonest Aveed-grasses, will 

 produce about 100,000 seeds each. Purslane, pigweeds, speedwell, and 

 Canada fleabane will even exceed this number. Individual plants of many 

 other species of common weeds produce seeds ranging high in thousands. 

 It is readily seen that at this rate of seed production it is not necessarj' for 

 very many plants to reach maturity in order to keep the soil well seeded. 



Blatehley stated, in his Indiana Weed Book, that "Those weeds which 

 are most common and successful in cultivated fields are in general those 

 which by reason of a quick growth are enabled to produce and ripen an 

 enormous number of seeds." 



Aside from being able to seed the gi'ound a])undantly most of the weed 

 species have also i)r()vided their seeds with excellent protective coverings 

 against loss of vitality when unfavorable conditions previ-ni tlKMr germination. 

 Species of Rumex, Plantago, Polygonum, Amaranthus, Chaetochloa., and 

 the Mustard family especially are well known for their al)ility to remain 

 viable for many years while buried deep in the soil. Seeds of the members 

 of the mustard family owe their longevity, in part, it is claimed, to the great 

 preserving power of the oil which they contain. 



r*rofessor Beall' found by aetu?l tests that "Shepherd's Purse, Mustards, 

 Purslane, Pigeon-grass, Pigweeds, Peppergrass, Mayweed, Evening Prim- 

 rose, Smartweed, Xarrow-leaved Dock, two Chickweeds, survive when 

 buried in the soil thirty years at least. . . ." 



J. S. Grennell,'- commenting upon the wonderful vitality of mustard 

 seed, made the following statement: "We have known of a piece of ground 

 that had not been ploughed for thirtj^ years at least; which, after the first 

 ploughing in spring, was yellow -with the charlock. . . ." Mr. Grennell 

 also stated that "A blackish earth was found beneath an old building known 

 to have existed over two hundred years; when this earth was spread abroad, 

 a quantitj' of marigold came up all over it, although it had never been seen 

 in that place." 



It does not seem possible that the seed of this particular weed would 

 retain its vitality for two hundred j'ean, but such evidently was Mr. Gren- 

 nel's observation. 



I Michigan Agricultural Experiment Station Bulletin No. 2G0, p. 105. 

 * Report on Agriculture of Massachusetts, 1861, p. 106. 



