12 proceedings of the academy op [1888. 



January 31. 

 Mr. Charles Morris in the chair. 



Twenty-eight pei-sons present. 



Mimicry among Plants. — Prof. J. T. Rothrock remarked that 

 among animals mimicry is usually related to the safety of the indi- 

 vidual, or less frequently to the ease by which it may conceal itself 

 and thus more readily capture its food. Whatever may be the cause 

 of mimicry among plants, or by whatever governing forces one plant 

 in the long run, may come to resemble another more or less remotely 

 related to it, it is clear that neither of the causes which are associated 

 with mimicry among animals can obtain in the vegetable kingdom. 



These mimetic cases ma}^ conveniently be ranged under two heads. 



1. Those in which we find the resemblances between plants in 

 groups clearly distinct. The lower of these may sometimes well be 

 called anticipating or prophetic types. 



2. Those found between plants in the same natural family, where 

 the descent within recent period, of one from the other, may rea- 

 sonably be supported by all who admit the doctrine of evolution. 

 This resemblance is of course often merely external, disappearing 

 under even the slightest examination ; as, for example, when one 

 glances hastily at a specimen, particularly an herbarium specimen, 

 oi Zygadeniis elegans Pursh, and then compares it with a narrow- 

 leaved specimen of Sivertia perennis. There are few who will not be 

 struck with the likeness, yet the former is a well njarked represen- 

 tation of the monocotyledonous group, and the other as evidently one 

 of the dicotyledonous plant. It is somewhat startling to find 

 along with marked points of distinction that there exist certain struct- 

 ural resemblances ; thus one may well compare the unusual mark- 

 ings found on the bases of the perianth divisions in Zygadenus 

 with the equally unusual gland found at the base of the petals in 

 Swertia. There is in these resemblances nothing which can in any 

 sense be called prophetic, because the relationship between the ex- 

 amples is quite too remote. 



The case is, however, somewhat different when one compares the 

 shape of some of the young liverwort with the prothallus of some 

 ferns. Here the resemblance is often very marked and the line of 

 relationship not so distant. It might almost be said that the perma- 

 nent form of the liverwort clearly resembled the early, transient 

 form of the fern. 



Or, as another instance, compare the protonema of a moss before 

 the shoot appears which is to develop into the erect aerial branch, 

 with one of our filamentous algse. Here again we have so marked 

 a general resemblance that it may well enough be classed with the 

 prophetic types. 



