60 3IASSACHUSETTS HORTICULTURAL SOCIETY. 



chess, Canada thistle, dodder, wikl mustard, sow thistle, creeping 

 buttercup, wild chamomile. Such seeds, though they may be 

 scarce in a sample, would readily spread throughout a field. In 

 the case of dodder, Kussian thistle, and some other weeds, no 

 commercial seed is worth sowing if it contains a single seed of 

 these species which is capable of germinating. 



The third cause of poor seed, namely, low vitality, furnishes 

 the greatest argument for seed control. In this respect the 

 buyer, under present conditions, is most likely to be defrauded, 

 and in such a manner that it is very difficult for him to obtain 

 redress. 



Most people judge of the germinating quality of seed from its 

 appearance. If plump, sound, and glossy it is presumed to be 

 germinable. Some go so far as to throw a handful of seed upon 

 a hot stove ; if it pops open suddenly it is supposed to be good. 

 Others test their seed by placing a small quantity in water ; if it 

 sinks it is thought sound ; if it floats it is considered dead. 

 Neither test is at all satisfactory. In the latter case a layer of 

 air closely enveloping the seed often keeps good seed afloat, while 

 poor seed may sink as readily, since the specific gravity of seeds 

 is greater than that of water. 



The appearance of seed cannot be relied upon in forming an 

 estimate of germinative ability. An artificial gloss is often 

 given to seed in the process of cleaning. Modern seed-cleaning 

 machinery is constructed not only to take out foreign matter, 

 but also, in many instances, with attachments which clean the 

 surface of the grains. The rubbing of tlie seeds together, of 

 itself^ gives them a glossy appearance. Sometimes polishing 

 brushes are used with the express object of making old seed look 

 like new. Cases are even known where seeds have been rubbed 

 against oiled surfaces for the same purpose. 



Without stopping here to discuss the subject of possible injury 

 to the seed coat which any artificial treatment is likely to pro- 

 duce, — a belief which prevails among the best seedsmen of the 

 country, for which reason such seedsmen do not use polishers, — 

 it is evident that a glossy surface affords no certain criterion of 

 the vitality of seed. Furthermore, there is not always strict 

 uniformity in the color of seeds, even of the same variety. Dull- 

 looking seeds often germinate better than shiny ones of the same 

 species. Nevertheless it is true that some seeds, especially the 



