12 INTRODUCTION 



In most of the lines of evolutions it is easy to 

 point out the most developed type of family, for it 

 exhibits a sum of well denned, constant character- 

 istics; but it is very different in regard to the low- 

 est or most ancestral types of a series, for the very 

 reason that it bears the germ of many variations, 

 and even partakes of characters which still connect 

 it with different branches of its own ancestral line, 

 but which have been obliterated in the more speci- 

 fied characters of its modern descendants. 



As such ancestral lines usually branch repeated- 

 ly, each branch the prototype of a line of evolu- 

 tions, the difficulty of finding the ancestral start- 

 ing point of modern well defined families, may be 

 imagined. 



Our own Calif ornian Calycanthus may serve as 

 an example of such an ancestral type or starting 

 point. It is intermediate between Rosacea and 

 Myrtacepe, so that with equal plausibility it may be 

 considered the first step to each of these evolu- 

 tions. At the same time it partakes of the charac- 

 ters of the Monimiaceae, which are themselves an 

 ancestral type of equal ambiguity, leading on one 

 side through Myristica to the Lauraceae, on the 

 other through Anona to Dilleniacere, and to Ra- 

 nunculacese, combining by these different relation- 

 ships tbe two primary divisions of Dicotyledons; 

 Calycinone with the AphanocyclicaB. 



Here we have one of the centres from which 

 modern types have radiated, and there is but little 

 doubt that several such centres sprang from a prev- 



