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TELLS ABOUT PRIMROSES „ 



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Professor DeVries Speaks at the Lowell 

 Institute About His Owi Experiments 



The lecture given last evening by Pro- 

 fessor Hugo DeVries— his third— in his 

 Lowell Institute course on "Evolution of 

 Plants," was a pleasant ramble for an hour 

 in his own garden attached to the Univer- 

 sity of Amsterdam. It was the story of his 

 experiments with evening primroses, the 

 work that has made him famous. 



In a field on the edge of a forest this 

 Dutch botanist one day found a very large 

 number of evening primroses. These are 

 yellow flowers, not related to the other 

 primroses, which open in the early evening 

 and remain open all night. In the field 

 DeVries noticed some of the flowers dis- 

 tinctly different from the others and took 

 them home for experimentation. 



"What he' discovered through long years 

 of investigation is that of the evening prim- 

 rose of Lamark (O. Lamarkiana) if the 

 flowers be carefully pollinated so as to ex- 

 clude outside mixtures and produce a pure 

 race, ninety-eight plants from every hun- 

 dred seeds will be regular,, one a dwarf, 

 and one a bending form. This proportion 

 held true in years of experiment. The 

 dwarf will breed true, and produce only 

 dwarfs, but the bending one must be arti- 

 ficially pollinated, for its own pollen never 

 ripens. Other varieties, mutations they are, 

 have been observed and one, a giant, has 

 appeared once only in all these years. It- 

 has been bred, but its like has not come 

 again through nature. One or two other 

 forms are likewise rare. This is evidence 

 that Darwin's small gradiations between 

 species in their evolution one from another 

 is an error, and that new forms are pro- 

 duced suddenly. 



The photographs which Professor DeVries 

 showed in abundance, presented every phase 

 of the plant and garden. 



In his university garden a large space is 

 walled and roofed with wire netting. With- 

 in this are the beds, the different groups 

 being separated. Various devices are used 

 to prevent undesired kinds of pollination. 

 Paper bags are placed over the spikes or 

 flowers, and for some plants an insect-proof 

 wire house is used. One part of the garden 

 is roofed with glass but with ample ventila- 

 tion, designed for the older plants whose 

 roots strike five or six feet into the ground, 

 and which need no other moisture. 



PLANTS AND THEIR ENVIRONMENT 



They Do Not Change with Shift in Loca- 

 tion, Says Professor DeVries 



Professor Hugo DeVries's final lecture in 

 his Lowell Institute course was directed 

 against the idea that environment has 

 anything to do with the changes of form of 

 plants. In the distribution of plants this 

 has been used for an argument, but it 

 proves to be untrue. ' When studied ii 

 luvgt divisions of the world f e - 

 are to be found outside the div 

 which they belong, although some are 

 be found in contiguous parts of two divi- 

 sions and the study must be made both of 

 large migrations and of the small ones. 

 Some plants were shown on the screen with 

 very small distribution, while others, like 

 the sage bush, have wide distribution. The 

 argument here turned rather to the sug- 

 gestion that these plants are desert plants, 

 no,t because they will not grow as well or 

 better in moister climates, but because they 

 are better suited to the places in which 

 they live than the other plants. Environ- 

 ment will kill off plants to which it is not 

 suited, but it does not affect those which 

 can survive under the new conditions. 



"The human species is older than its en- 

 vironment," said Professor DeVries," for it 

 existed before the glacial period, and the 

 same is true of many plants and animals. 

 The swamp cedar is an example of this 

 kind. Its fossil remains show that it is 

 practically unchanged, but at the same time 

 it is living today under very different condi- 

 tions and in the midst of a different flora, 

 most of its ancient companions being now 

 extinct. Life conditions, therefore, are not 

 due to adaptation. Plants like other or- 

 ganisms live in the midst of a constant 

 struggle, and their places are the ones that 

 they can maintain rather than the ones I 

 ideally the most suited fa them. The ' 



desert plant which would do better in 1 

 moister places is probably pushed out By 

 other plants that can do better still In the 

 moist places. 



The water pest, a river weed, came into 

 Europe from America seventy years ago. 

 It is all over the Continent. It has mere- 

 ly adapted itself to new conditions, but 

 is the same species. In the same way 

 a salt weed which came to America from 

 Europe is widely spread, Professor De- 

 Vries having observed it on the shores, 

 of the Great Salt Lak. in Utah. The 

 water hyacinth is mother example. It 

 came from South America to the South 

 and has homed itself in the rivers so 

 well that motor-boats and even large 

 steamers cannot make their way through 

 its tangled mass. It has not changed in 

 the least. The flora of the Sahara Desert 

 originated when the country was as fer- 

 tile as any other portion of the world. 

 The withholding of rain, which has prob- 

 ably been by slow stages, has caused 

 the dying out of many kinds of plants, 

 but it has not made any change in those 

 that survive. 



