. Textbook of pastoral and agricultural botany, for the study of the injurious and useful plants of country and farm. e. Thisweight is more or less influenced by the shape and size of the seeds whichpermit them to form a more or less compact mass, and also by the 266 PASTORAL AND AGRICULTURAL BOTANY shape of the vessel. Small sized, or withered seeds give a smaller vol-ume weight than large plump seeds. The number of seeds in any measureincreases with the volume weight and the weight of the indi\ddual seedsdecreases in like ratio. With cereal seeds the absolute weight of theindividual seeds in
. Textbook of pastoral and agricultural botany, for the study of the injurious and useful plants of country and farm. e. Thisweight is more or less influenced by the shape and size of the seeds whichpermit them to form a more or less compact mass, and also by the 266 PASTORAL AND AGRICULTURAL BOTANY shape of the vessel. Small sized, or withered seeds give a smaller vol-ume weight than large plump seeds. The number of seeds in any measureincreases with the volume weight and the weight of the indi\ddual seedsdecreases in like ratio. With cereal seeds the absolute weight of theindividual seeds invariably increases with the volume weight. Chemicalanalyses show that the higher the volume-weight ,the better the ediblequality of cereal, or starchy seed. Hence it is important to determine thevolume weight. To estimate the real, or agricultural worth of a seed sample, we mustcombine the purity and \dability percentages, thus: = Real, or Cultural Worth in terms of per cent. lOO Means of Detecting Source of Seeds.—It is important to have areliable means of detecting the source of supply of seeds. Wittmack was. Fig. 119.—Wild carrot, c, natural size; a, h, front and edge views. {Taken fromSeed Testing Us Uses and Methods, North Carolina Agricultural Experimeni Station , 1894.) the first scientific man to interest himself in this question, and in 1873, herecognized a red clover as American owing to the presence in it of seeds ofAmbrosia. Sometimes the appearance of the seed itself—the metalliclustre of its coat—prpclaims its origin. Stebler calls those weed seedswhich indicate the origin of the seed source indijators. Other seeds not asreliable, but still helpful, he calls companion seeds. Of the weed seedsfound in red clover a few such as ragweed, spurge, field dodder, Practedand black-seeded plantains, spiny sida, ladys thumb and vervain indicatethe American origin of the seed in other words are source indLators. Onthe other hand clover dodder (Fig. 120), scent
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Keywords: ., book, bookcentury1900, bookdecade1920, booksubjectpoisonousplants
