GIXKGOALES 



39 



In 1809 Van Tieghem * published his view that the stalk 

 represents a petiole, and that the two ovules are determined by 

 the two characteristic lobes of the blade. According to this 

 view, the whole structure stands for a single carpel. Van 

 Tieghem further sees in the collar at the base of each ovule a 

 reduced arillus, which name of course gives no clew to its 

 homology. In 1872 Strasburger 3 published the view that 

 the stalk is a shoot, and that the collar is the mdiment of the 

 first pair of leaves of a secondary shoot. It would follow that 

 the whole structure is an inflorescence bearing two flowers, and 



FIG. ZQ.Giitkyo biloba: A, dwarf branch bearing leaves and young ovules; J?, a stam- 

 inate strobilus; 6 1 , more enlarged view of a portion of B; Z>, longitudinal section of 

 a young ovule ; E, a ripe seed associated with an undeveloped ovule. A, B, E, 

 natural size ; C*, Z>, enlarged. After GOEBEL. 



that any such structure as a carpel is suppressed. In 1879 5 

 he modified his view as to the character of the collar, having 

 concluded, as Van Tieghem had thought, that it represents an 

 arillus. He cited cases in which a stalk bore four ovules, each 

 upon a slender stalk of its own; this of course was a strong 

 argument in favor of the view that the whole structure repre- 

 sents a shoot. In 1873 Eichler 4 published his view that the 

 collar represents an outer integument, which is not necessarily 

 inconsistent with the preceding views that it stands for an 

 arillus. Later 7 he called the collar a rudimentary carpel, and 

 4 





