Crossword-Solution: VRIES 5 letters, 4 clues 🏆 scrabble score: 8

The plant from which de Vries saw numerous "species"--his "mutations"--arise was not, as he assumed, a WILD SPECIES that had been introduced to Europe from America, but was probably a hybrid form which was first discovered in the Jardin des Plantes in Paris, and which does not appear to exist anywhere in America as a wild species.

This gives a severe shock to the "Mutation theory," for the other ACTUALLY WILD species with which de Vries experimented showed no "mutations" but yielded only negative results.

With the permission of Professor de Vries, the following extract is quoted from a letter in which he replied to the objection raised to his reading of the passage in question: "As to your remarks on the passage on page 6, I agree that it is now impossible to see clearly how far Darwin went in his distinction of the different kinds of variability.

First we must, as de Vries has shown, distinguish real, genetic, variation from FLUCTUATIONAL variations, due to environmental and other accidents, which cannot be transmitted.

The "mutation-theory" of De Vries ("Die Mutationstheorie", Leipzig, 1903.), that would explain the origin of species by sudden and saltatory variations rather than by gradual modification, is regarded by many botanists as a great step in advance, but it is generally rejected by zoologists.