104 Riley Some Interrelations of Plants <tnd Insects. 



pends the one oil the other. As palaeontology shows, and as 

 Professor Ward has more particularly so well explained, there 

 was for ages no vegetation but the flowerless plants. The first 

 were the low cellular cryptogams, consisting chiefly of marine 

 alga?, and these, the lowest and first organisms upon the planet. 

 have endured through all geologic time and obtain to-day. 

 Next, beginning in the upper Silurian and reaching their max- 

 imum in the Carboniferous, came the vascular cryptogams, of 

 which the ferns constituted the bulk. Arborescent and gigan- 

 tic compared with present forms, they mingled with the now 

 extinct Lycopodinese to form the bulk of the forests of the coal 

 period. Then came the Phsenogama, or flowering plants, and 

 in this great division the Cycadacea? and conifers? (pines, firs, 

 etc.) were the chief forms during Mesozoic times. So far the 

 seed has been exposed. Now come the Angiosperrns, in which 

 the seed is protected in the ovary or pericarp, and the Monocoty- 

 ledons (palms, sedges, etc.) precede the Dicotyledons, while of 

 these last the Apetalre, Polypetalie, and Gramopetalse succeed 

 each other in the order of their naming. 



In brief, to use his own words, the development has been from 

 the simple to the complex ; from the flowerless to the flower- 

 ing ; from the endogenous to the exogenous ; from the apetalous 

 to the gamopetalous ; and this succession corresponds to the 

 best systems of classification of existing forms. 



Both Cryptogams and Phsenogams began existence during 

 the Silurian, and there has been a race for supremacy ever since. 

 with our present flora as the result. It is also a fact of the 

 greatest significance that the same palseontological evidence 

 which gives us this record also tells us that there has been a 

 corresponding'development of insect life, from the lower Xeu- 

 roptera and Orthoptera, which prevailed in the days when 

 Anemophilous plants reigned, to the higher Lepidoptera and 

 Hymenoptera, which appeared only as the higher flowering 

 plants developed in the Jurassic and Cretaceous. 



I do not hesitate, in this, connection, to refer to another of 

 Professor Ward's conclusions set forth in one of his interesting 

 articles, namely, that, most of the higher flowering plants would 

 speedily perish were insect aid withdrawn, and that but for 

 such aid in the past w r e should now be without most of our 

 gorgeous flora, and that insects have actually paved the way for 

 man's existence by the part thev have played in the develop- 

 ment of fruit and nut bearing plants. 



