24 



general appearance, and in leaf and branch characters, but they ripened their 

 fruits at the same time — that is, just between the two other species; their fruits 

 were of the same size, shape and color; they colored their leaves in the same 

 way in the fall, and dropped them at the same time. 



These observations, as I have pointed out, were not based on experiment, 

 since we did not produce the hybrid ourselves, but it seems to be beyond doubt 

 that it is possible to produce experimentally a plant which looks exactly like 

 A. atropurpurea by cross-fertilizing the two other species. If that were done, 

 would that be a proof that A. atropurpurea is of hybrid origin? Not necessarily, 

 I believe. And, at this point I wish to emphasize the fact that the other form 

 of the hybrid, the var. typica, has never been found wild as yet, as far as I am 

 aware. And, why could not by some joke of nature an intermediate form origi- 

 nate as a mutant from one species which resembles a hybrid but is not? Should 

 it be possible to prove mutant origin for A. atropurpurea, perhaps by cyto- 

 genetic tests, what would the taxonomist do? Should he keep two plants sepa- 

 rate under two different names which in outward appearance are exactly alike, 

 or should he combine under one name two plants which in origin are funda- 

 mentally different? 



This suggestion may sound like hair-splitting, but I do not believe that 

 it is. If we do believe in evolution, we have to believe that many plant-forms, 

 which we now call species, have originated not as mutants, as they are usually 

 explained, but by cross-fertilization. As long as they remain constant, the tax- 

 onomist may say that it does not matter how they originated; but what about 

 the numberless garden-hybrids which plant-breeders have originated, which 

 also come true from seed and remains constant in their characters? No tax- 

 onomist suggests calling them "species," for the simple reason that their hybrid 

 origin is known. Even a binomial name which is such a great practical help to 

 the horticulturist is usually denied to them. 



And this leads me back to where I started. I have no solution to suggest 

 for the problem of what is a species, but I believe that a close cooperation be- 

 tween the horticulturist and the taxonomist might help to find a solution for 

 some of the puzzles which I have presented. 



Respectfully submitted, 



Forman T. McLean 



Secretary 



Meeting of November 2, 1932 



The meeting was called to order at Schermerhorn Hall, Co- 

 lumbia University, at 8:15 p.m. by President Sinnott. There 

 were 200 people present. 



Professor Owind Winge of the University of Copenhagen 

 discussed "Sex Determination in Melandrium and Lebistes." 

 He illustrated the inheritance of a number of color characters 

 and other peculiarities by colored lantern slides. 



