I 



4 

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1902] ATQ TES ON SASSA FKAS 433 



ceae, but even in the existing Sassafras, aside from some striking 

 exceptions, the majority of the leaves on full grown trees are 

 simple. It is doubtful if we shall ever know these ancestral 

 forms as such even if found, as they will probably be described 

 as Laurus. In all probability the ancestral forms of all the dico- 

 tyledons were developed in an area remote from localities where 

 fossilization was going on, as suggested by MacMillan '^ In 

 Liriodendron the variation from the oldest to the youngest leaf 

 on a shoot from the modern form epitomizes the phylogeny in 

 a general way. If the like holds good in Sassafras it would hint 

 at an ancestor with trilobed leaves, for in all the forms which I 

 have examined there seems to be a somewhat constant gradation 

 from the outer (older) two or three-lobed leaves, through the 

 simple lanceolate or ovate-lanceolate bud leaves, to the spatu- 

 late-ovate bud scales, which persist to form the involucre of the 

 flower cluster. 



Paleobotanists associate the name Sassafras with lobed leaves, 

 and I do not know of a single specimen of a simple leaf which 

 has been described as Sassafras, although several leaves referred 

 to other species might easily be forms of Sassafras, as for 

 instance Ci?inamomiim Heeri Lesq. from the Dakota group". 

 Premising this much what shall we say of the relations of the 

 numerous fossil species of bilobed and trilobed leaves which 

 have been referred to this genus, ranging in time from the Poto- 

 mac formation upward ? While some are undoubted forms of 

 Sassafras and have always been known as such, others are just 

 as undoubtedly not forms of Sassafras at all. Very diverse opin- 

 ions have been advanced as to their proper position. Saporta 

 questions all of the references of trilobed leaves to Sassafras, 

 and suggests their affinity with Aralia, pointing out their resem- 

 blance to the Central American genus Oreopanax. Araliopsis 

 has always been a convenient shelf on which to place these 

 leaves, but it seems to me that such references are altogether 

 unsatisfactory. Lester F. Ward ^^ is of the opinion that it is 



'^ The probable physiognomy of the Cretaceous plant population. Amer. Nat, 

 27: 336. 1893. 



"Fl. Dak. Group, p. 105,//. /J. fig^ /. 



" Proc. Nat. Museum 11: 39-42. ph, 17-22. 1888. 



