86 ~ THE MICHIGAN ACADEMY OF SCIENCE. 



to planls than to animals." If we believe that evolution has taken place 

 in plant life in the past it is very probable that it is still taking place, 

 because vro have ho record nor proof when or where it stopped. If evo- 

 lution is si ill going on we can not consider species as fixed, but as vary- 

 ing way-marks in the processes of evolution. 



I feel that all my hearers believe that we are living in the midst of 

 species making, and that they are being made by the processes above 

 mentioned as the causes of plant variation. But where is this work 

 taking place? Where is the laboratory where new species are being 

 turned out? The botanist says in the unmolested .forest; on the un- 

 broken prairie; upon the rocky mountain side; and in the virgin valley. 

 The horticulturist says the same, but in addition he says the garden, the 

 nursery, the cultivated field, the road side, yes, every nook and corner of 

 the earth is Nature's laboratory for species making. 



Are there any species being made in the garden? This is a question 

 still open for discussion; it is one not yet answered uniformly. But 

 as species have been formed by variation caused by environment and 

 crossing followed by natural selection, we find these conditions in the 

 garden, only that man aids in the process, thereby hastening the results. 

 In other words, Nature by the aid of man accomplishes in a short time 

 what she alone would accomplish in a long time. 



It appears as though species do originate in the garden ; or at least 

 plants have originated which vary greatly from other plants of the same 

 species. \ 



It is agreed by all that when a well defined difference between indi- 

 vidual plants of a given genus exists, and this difference is apparently 

 constant, that such plants are placed as different species. As in case of 

 Hepatica triloba and H. acutiloba whose only difference is in the shape 

 of the lobes of the leaves and that the one sometimes has five lobes instead 

 of three. 



Another example of the minimum difference between authorized spe- 

 cies is Yitis sesetivalis as compared Avith V. bicolor; the differences be- 

 tween these are small. According to Britton and Brown the principal 

 differences are, that the color of the fruit of one is bluish-black, while 

 that of the other is black; the berries and seeds of one are a little smaller 

 than the other. The inflorescence of one is somewhat more compact 

 than that of the otlier; the leaves of one are inclined to be three-lobed 

 while those of the other are three or five-lobed; the color on the under 

 side of the leaf of V. bicolor is bluish glaucous. An examination of a 

 lot of herbarium specimens showed a very great similarity between the 

 two species; the leaves of both are very much alike in shape and size in 

 different individual specimens; the fruit is nearly the same. Other 

 plants which differ in but a few points are Melelotus officinalis and M. 

 alba ; Lepidium Virginicum and L. apetalous ; and many species of the 

 genus Rosa. 



Now let us look into the garden and see whether there are any plants 

 of the same species which vary from each other as much as the above 

 authorized species. The erect tomato, a descendant of Lycopersicum 

 esculentum is a plant which varies from its parents in several respects. 

 It differs in its general habit of growth, it being low and upright with 

 thick stocky stems thickly covered with pubescence, the leaves are 

 smaller, rugose and greatly reduced in size and parts. Its inflorescence 



