271 



MIMICRY OF SEEDS AND FEUITS, AND THE 

 FUNCTIONS OF SEMINAL APPENDAGES. 



By S. Le M. Mooee. 



(Preliminary Notice.) 



The fierce contest for existence everywhere iDroceeding around 

 us, and modifying and differentiating in such extraordinary 

 diversity both animals and i^lants, is, I venture to think, exhibited 

 by seeds in no dubious or ill-defined outline. Indeed, one has but 

 to consider the tenacity shown by seminal characters, which 

 renders the seed one of the most, if not the most, valuable of aids 

 to the sj^stematist, and the amazing difference in size, shape, 

 colour, marking, &c., of seeds, to have a strong suspicion that 

 Natural Selection has had some influence in moulding their history. 

 The enemies of seeds are legion ; if, therefore, they possess no 

 means of escaping from them, and are not produced (as is indeed 

 rarely the case) in countless multitudes, spermology is the only 

 department of nature showing structures unadapted to their 

 environment. The success of vegetation belies this conclusion. 

 How then are seeds enabled to carry out with such unfailing 

 punctuality the duties entrusted to them ? 



Putting aside consideration of the means of protection against 

 purely physical agencies, for which the testa seems aU-sufficient, 

 it is evident that seeds may be protected by their smallness, which 

 enables them to keep out of notice of then- larger would-be 

 enemies ; when, too, we remember that, other things equal, the 

 smaller the seeds the more numerous they are, and that by 

 reduction in size they are liable to become the prey of insignificant 

 creatures with but feeble powers of injury, we must, I think, 

 recognise in this the vera causa of the so-general smallness of seeds, 

 such reduction being in each case governed by the habit of the 

 plant, by the chemical constitution of the matters stored up for 

 the nourishment of the seedling, and by other circumstances. 

 Acridity has long since been recognised as a selection-induced con- 

 dition whereby seeds are enabled to render themselves obnoxious 

 to insects ; the secretion of volatile oils by the testa, &c., may also 

 effect the same purpose ; this is certainly the function of the vittaB 

 of the umbelliferous mericariD, which leads to the mention of 

 adnation in many cases of the ovary to the calyx, indehiscence of 

 the fruit, and the various ways of thickening, &c., of the latter, 

 methods directly subservient to protection of the seed. Then 

 again a thick testa is of great service in protecting the seed (or 

 fruit) during its passage, through, say, a bird's alimentary canal ; 

 the sculpturings, too, such frequent and constant seminal marks 

 seem to be especially valuable against small insects, which are 

 thereby hindered in their ravages. Often, too, quick germination 

 is a very great advantage — this holding, of course, almost 

 exclusively in the tropics — and soil-like colouration, as well as to a 

 certain extent germination under water ; to these may be added a 



