CHAP. v. SELECTION OF SEED. 821 



question is to propound another, which we have already anticipated, 

 namely, Is it worth while preparing at great expense a good seed-bed, 

 if you are going to foul it by sowing thereon dirty seed ? 



In every kind of grass and clover seed, and indeed in all kinds of 

 farm seeds, there may occur, and usually do occur, the seeds of certain 

 weeds. In Chapter I. of Book the Tenth (p. 893) are stated for each kind 

 of grass seed the weed seeds most likely to be found in it. Obviously, 

 no one would willingly, or purposely, sow seeds of plantain, sorrel, 

 self-heal, buttercup, cranesbill, wild-carrot, dock, blue-bottle, Yorkshire 

 fog, or soft brome, if he could possibly help it, and yet it is to be 

 feared that such seeds as these find their way into the seed-barrow in 

 much greater proportion than might be imagined. Hence, in pur- 

 chasing seed it is desirable to examine the sample very carefully and 

 to satisfy oneself that all the seeds are alike ; if there is even a small 

 proportion of seeds unlike the bulk, the sample should be rejected. 

 Experience shows that the unaided eye is scarcely competent to detect 

 impurities in grass and clover seeds. If, however, the sample is spread 

 out on a sheet of white paper and slowl}' passed under a magnifying 

 glass, it is sometimes surprising to see the quantity of impurities thus 

 detected. In the case of grass seeds more skill is required, for 

 certain species are liable to contain worthless grasses, the seeds of 

 which bear so close a resemblance to those of the true sample, that 

 detection becomes difficult. Yet another class of injurious impurities 

 are such parasites as dodder and ergot the former in clover seed, the 

 latter in grass seed. With a little care these are by no means difficult 

 to detect, and probably the best advice to give regarding these pests is 

 that the samples containing them should be rejected, and not used for 

 sowing under any circumstances whatever. 



Granting that a sample is pure, and that it is of satisfactory ger- 

 minating capacity, there remains the question : Is it what it purports 

 to be ? Is it true to the species ordered ? In many cases there is no 

 difficulty in answering this question. In some, however, it is not 

 only difficult, but impossible. For example, who can say whether a 

 sample offered as that of fiorin grass (Agrostis alba stolonifera) at Is. 

 per Ib. is not that of twitch (Agrostis alba), which is worth less than 

 nothing ? Who can distinguish the seeds of cabbage from those of 

 kohl rabi, of swede from rape, or of turnip from kale ? The skill of 

 the botanist and the dexterity of the microscopist are alike ineffectual 

 in cases such as these, in which the seeds of different plants are exactly 

 alike. The resemblance in each case is a strong and unmistakable 

 family likeness. 



A still more difficult problem presents itself in the case of the seeds of 

 improved and unimproved varieties of the same plant. The best mangel 

 grown is only an improved variety of the wild beet of our coasts, and 

 perennial white clover has the same ancestry as common Dutch. In the 

 one case the plant has been trained and cultivated, and thereby improved; 

 whilst in the other it has continued to run wild. But the improve- 

 ment, be it observed, has not extended, to the seed in so far, that is, 

 as visible characters are concerned simply because the seed has not in 



