1896.] Botany. 489 



shown by the twisted pods of species of Prosopis), whilst the seeds 

 which arise from the two sides of a carpel are diverse. The order of 

 development in the carpel may depend on the direction of the nutri- 

 ment, and on the lines of least resistance in the crowded condition of 

 young organs resulting in right-handed and left-handed ovules. The 

 outcome is that in the adult plant the whole phyllotaxy. including the 

 floral structure and ramification of the entire organism and its inflor- 



aud of a different order in other plants of the same species. Whether 

 this is of any special advantage to the grown plants I cannot say ; but 

 possibly by imparting different habits of growth to the various" mem- 

 bers of crowded vegetation, it may cause them to separate from each 

 other, and so may diminish the intricate interlacing which is so injuri- 

 ous to gregarious plants. 



Now that the season of vegetation is returning it is to be hoped that 

 some of our young botanists will make and record their observations 

 on this subject. We want especially to find out exceptions, apparent 

 or real. My first paper was incorrect as to the supposed antidromy of 

 rows of grains in the case of maize; dissection seemed to teach this ; 

 but I might have foreseen that the ear is just like the male panicle, 

 having a disorderly crowd of grains rearranged by a secondary process 

 into orderly rows, each row, however, including both dextral and sinis- 

 tral grains. The case of the Bilsted L<< < \idnuibav ) is a puzzle, some 

 of the branches of the Bame tree having dextral phyllotaxy, and others 

 having sinistral phyllotaxy : this is the only case of the true internal 

 antidromy known to me, though I shall not be surprised by the dis- 

 covery of other similar cases. A somewhat similar condition is re- 

 ported to me by Prof. Francis E. Lloyd, of Forrest Grove, Oregon, in 

 ten cases of Acer cirnmitinn. Perhaps these cases are allied to that of 

 plants arising from roots talks, as Iris and Calla, Helonias, Nvjilmr, etc.. 

 in which different plants arising from the same rootstalk are antidro- 

 mic. It will be worthy of examination whether sarin en tose plants, as 

 strawberry, and the Saxifraga described by Prof. Todd are antidromic 

 as between those grown from the same original stock. 



The phenomenon which I have termed didromy, where the same 

 member is twisted in opposite directions at its two extremities, seems 

 to me to be always related to the immediate life of the plant, and to 

 have no genetic significancy. The didromic twist of the awn of Dan- 

 t In, a in and other grasses, result- in the upper part penetrating an object 

 so soon as the lower part untwists by the application of water: that of 

 the long peduncle of 1 - the extremities, thus 



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