1902] NOTES ON SASSAFRAS 427 



4 



of the variations, necessarily brief, is followed by an examina- 

 tion of the numerous fossil leaf-forms which have been referred 

 to this genus, and their probable relations are pointed out. 



Simple leaves.^ — Greatest length 190°'"', greatest width 

 iQymm . gh^pc Varying from lanceolate, through ovate lanceolate, 

 to almost orbicular ; tip truncate, rounded, or cuspidate ; lateral 

 margins ascending at an angle of about 45"" at their base ; base 

 narrow and more or less decurrent on the petiole, especially in 

 young leaves ; texture from membranaceous to coriaceous. In 

 texture, however, as well as in general form and character of 

 venation, the leaves of a single tree proclaim their relationship, 

 so that particularly pointed lobes or the reverse, broad short 

 leaves or the reverse, very thin or very thick leaves, whether 

 simple, bilobed, trilobed, or multilobed, all have the same aspect. 



Bud leaves are always narrow, with ascending laterals forming 



an angle of 30° or 



J 



when they are about 60 or 70°^°" in length, had the primaries and 

 secondaries indistinguishable in 68 per cent, of the leaves exam- 

 ined, in numerous older leaves the primaries are only to be 

 distinguished by their greater length, are rarely opposite, and 

 sometimes have a pair of secondaries below them nearly as large. 

 There were an equal number of primaries and secondaries on 

 each side in 60 per cent, of the leaves examined. 



Bilobed leaves. — The bilobed leaves are more variable than 

 the simple leaves, varying in outline from oblong-lanceolate to 

 nearly orbicular. The lateral lobe may be broadly rounded or 

 even reduced to a small blunt protuberance, or it may be nar- 

 rowly acute, extending at almost right angles, or directed upward 

 and not extending above the basal half of the leaf; or it may 

 extend as far as the tip of the main blade and nearly equal it in 

 size. The sinus varies from a slight wide depression extending 

 only one-eighth of the distance to the midrib, to one extending 

 three-fourths of the distance, and wide and obtuse or narrow and 

 acute. Venation, of course, is inequilateral. Eighty per cent. 

 have first secondary lower, and primary generally higher on the 

 lobed side. 



5 It is well to note that any statements made here refer only to the series I have 

 examined. 



