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The thirty-one specimens hiid before you are thouglit to repre- 

 sent four species, and many varieties. The seeds came from 

 France, but tlie plants furnishing them originally came from 

 widely separated localities. The differences which they exhibit 

 are in the color, shape, and hairiness of the glumes ; the color, 

 shape, and prominence of the corn beyond the glumes ; and the 

 open or compact growth of the panicle. If these differences wei'e 

 constantly exhibited together, — if the difference of shape were 

 always attended by a difference in color, and that color always 

 accompanied by the same hairiness and exsertion of corn, there 

 would be strong ground to establish specific differences. But 

 such is not the case. The specimens, placed side by side, ex- 

 hibit a complete gradation between the exti'emes of the series. 

 Those which vary most in shape are similar in color. Those 

 which differ in color are identical in shape. The hairiness and 

 the degree of exsertion are coexistent with the extremes of shape 

 and color. There are four which are especially interesting. Mr. 

 Olcott grew Broom Corn and Dourrha in rows on each side of 

 Sorgho Sucre. The result was a plant partaking equally of the 

 characteristics of the parents on each side. The eighteen vari- 

 eties of Imphee, thought to be so distinct that different native 

 names have been given them, exhibit every intermediate form 

 imaginable. Some glumes are nearly white ; some are specked 

 with brown and black ; some are all brown ; others all black. 

 Some have ovate pointed glumes of every hue ; others have 

 obtuse glumes with a broad, scarious point, or rounded glumes 

 with no point, through the same series of color. The corns ai-e 

 either enclosed or exserted through the whole series, irrespective 

 of color or form. Some of the varieties of Imphee present a 

 peculiar appearance, from the persistence and prominence of the 

 sterile spikelets ; some, differing in no other respect, have these 

 scai'ce visible ; and some have them not at all. Color and 

 hairiness are among the least reliable of botanical characters, 

 and should have but little weight in plarjts so closely allied ; and 

 the other differences are exhibited almost as prominently in dif- 

 ferent panicles of the same acknowledged variety. 



The question of the hybridity of species of plants has lately 

 received close and careful attention. M. Charles Naudin has 

 recently made a series of interesting experiments on the culti- 



