HEREDITY, AND THE ORIGIN OF SPECIES MACDOUGAL. 513 



more rapidly, germinates its seed more quickly, and makes more 

 numerous branches, and bids fair to be able to win out in a struggle 

 with the parent in all of the phases of the struggle. Gicjas is a more 

 vigorous form than the parent, and both it and rubHnerms show a 

 tendency to predominate when crossed with the parent. Brevistylis 

 Avas found in the original location from which the mutating strain 

 was taken, and as it has not appeared in any of the pedigreed cultures 

 of the parent type in twenty years and still maintains itself in the 

 original locality, it may be designated as a mutant which not only 

 has arrived, but has survived under perfectly natural conditions. Re- 

 cent cultures in the New York Botanical Garden from seeds of 

 Lamarck's evening primrose, sent from various parts of the world 

 where the species is under cultivation, demonstrate that it is not alone 

 the plants observed by De Vries at Hilversum that are mutating, but 

 the same derivatives are being given off in widely separated localities. 



The evening primrose of the Adirondacks and northern New Eng- 

 land, Oenothera cruciata^ has been found to give atypic individuals 

 conforming to a single type, which is also represented by specimens 

 that have been collected in a wild state; so that here, also, we have the 

 survival of a species which is still arriving in a large proportion of 

 the progeny. The great-flowered evening primrose, Oenothera grandi- 

 -flora^ of the Southern States has been grown during two generations 

 and it also is found to give derivatives, one or more of which appear 

 to be already represented in the flora of the region. 



One of the most interesting correlations to be made from a study 

 of the results of these observations is to be found in the parallel muta- 

 tions exhibited by the several species, in apparent contradiction of the 

 principle of radiate variation and mutation {allseitige Mutationen) . 

 Among these are to be mentioned the origination of a form with cru- 

 ciate flowers of the same general form as the Oenothera cruciata of 

 the Adirondacks, from the species known as 0. biennis in Holland, 

 which is not identical with any species known to grow wild in Amer- 

 ica. The same species has also been seen to give off a mutant having 

 the character corresponding to the mutant nanella, coming from La- 

 7narckiana, according to De Vries. Then an evening primrose of un- 

 known identity has been found on Long Island by Doctor Shull, far 

 removed from the locality inhabited by any other cruciate phint, and 

 strongly suggestive of a mutation from biennis or some other form 

 native to that locality. Such facts merely show that the forms borne 

 by nearly related species lie well within the limits of the morpholog- 

 ical possibilities in saltations and that they may be expected to be 

 duplicated in other observations. 



Scattered through the literature of botany and horticulture of the 

 last century are scores of records of the sudden appearance of sports 



