296 GYMNOSPERMS 



shoot, and so a leaf in the axil of another leaf is an impossibility. 

 Consequently the ovuliferous scale could not be a leaf, unless some 

 shoot could be so reduced as to become present only theoretically. 



In a transverse section through the bract and ovuliferous scale, 

 the bundles of scale and bract show a reversed orientation, the xylem 

 of the bundles facing each other, with the phloem outside; and this is 

 true, whether the bract and scale are free from each other or "fused" 

 into one structure. But the bundles of the bract connect below with 

 the vascular bundles of the cone axis, while the bundle of the ovulif- 

 erous scale connects above; consequently, with this connection, the 

 orientation is not at all peculiar, but only what should be antici- 

 pated. From a study of the bundles, Van Tieghem'^-'^ drew the con- 

 clusion that the ovuliferous scale is a leaf on a suppressed branch, a 

 conclusion which was later strengthened by the bundle situation in 

 the "double" leaves of Sciadopitys. 



Some claim that the cones of Araucariaceae are quite different 

 from those of the preceding families. The cone of Araucaria looks as 

 if it had a bract and scale, fused as in the Cupressaceae; and Dr. 

 Hannah Aase,' from a study of the vascular anatomy, is inclined to 

 believe that the structure is compound. Thomson ,^^* also studying 

 the anatomy, concludes that there is only a simple sporophyll, so 

 that the cone is simple, like the staminate cone. In the other genus, 

 Agathis, there is no such appearance of bract and scale. Taxonomists 

 separate the two genera on the presence (Araucaria) or absence 

 (Agathis) of a "ligule." The ligule of Araucaria has the position of 

 an ovuliferous scale, and looks like one (fig. 301). 



At present, we prefer to use the term "ovuliferous scale." Until 

 some decisive proof of some theory is produced, we shall continue 

 to believe that the bract of the ovuliferous cone is the homologue of 

 the sporophyll of the staminate cone, and shall guess that the ovulif- 

 erous scale — ^at least in forms with bract and scale — is a modified 

 shoot which, with or without leaves, bears the ovules. 



Unless some entirely new theory, different from all of these, can be 

 proved, the ovulate cone is compound, and, therefore, is not a flower, 

 but an inflorescence. 



The megasporangium. — All of the megasporangia. commonly 

 called "ovules," of the conifers are borne in strobili, which are defi- 



