264 Miscellaneous. 



It has been my fortune to have to show that in many cases where 

 variations liavc been charged to crossing by foreign pollen or by 

 other " conditions of environment," it was extremely probable that 

 the sole actor in the work was this unknown law of change : 

 while I have shown in many monotypic species, or in sjiecies re- 

 moved from all possibility of intercrossing with other species, that 

 the variations arc quite as wide as if there had been full opportunity 

 for the supposed laws of environment to operate. 



Here I will call attention to the interesting variations any one may 

 find in an hour's walk among Litiaria vulc/aris, the common yellow 

 toad-flax, in any district where the conditions are absolutely iden- 

 tical and the plant tolerably abundant. Let one gather in tlie walk 

 any specimen that seems to be slightly different from another, and 

 he will Ije amazed on comparing the handful to note how great the 

 difference. The foliage does not vary much, but some of the most 

 divergent flowers might pardonably be referred to distinct species, 

 did not the intermediate forms show that they were all of one family. 

 There are variations in colour and in form. In colour some are pale 

 straw and others deep yellow, while the palate varies from deep 

 orange to the faintest possible tinge of yellow. At times nearly all 

 the corolla, except the palate, is white instead of the normal tint, 

 and again are forms in which only the backs of the two upper seg- 

 ments are white. But the most interesting variations are in the 

 form of the lower lip. This is trilobed. Sometimes the lateral 

 lobes are so broad as to overlap each other, when the central lobe 

 seems hardly noticeable. At other times they are so widely sepa- 

 rated that the trilobed character is noticed at a glance. In some 

 instances the central lobe is scarcely produced, in others it is large 

 and broad, extending to the line of the lateral lobes. 



What has environment had to do with those widely variant forms? 

 The most diverse will often be found in proximity where no one 

 could suggest any difference whatever in the surrounding conditions. 

 It is an introduction from Europe, and has no close allies that any 

 one could name as likely to influence its pollination. Indeed, if 

 these were present, they would be inoperative, as the plant is here, 

 and probably everywhere, a close breeder, as I noted years ago. 

 The pollen-sacs burst before the corolla opens, scattenng the ferti- 

 lizing dust over its stigma, which is evidently influenced thereby 

 before the wind or insects have had any chance to operate. The 

 flowers can gain no advantage from any outside agency, usual with 

 those where insects have some opportunity to bring in foreign pollen 

 before it is too late. 



Aside from all this is the fact that the plants in any one given 

 locality but a few years ago sprang from possibly one, or at most a 

 few progenitors, which, introduced by accident from Europe, 

 escaped the cultivator's destructive hoc, and then spread, through its 

 progeny. 



There seems no escape from tlie deduction that the plant derives 

 from some pre-natal inlluence power to vary greatly, without anv 

 regard to the long periods of time sometimes called for, and wholly 

 independent of external intluenccs, — I'roc. AccoL Nat. Sci. PhiJad 

 May 20, ISDl, p. 2(i!». 



