CONIFERALES (PINACEAE) 251 



tation. The conclusion seems evident that the ovuHferous structure 

 of araucarians and of podocarps is of the same nature, and that it is 

 a simple megasporophyll. That in so large and ancient a group as 

 the Pinaceae both simple and compound ovulate strobili should be 

 represented, would not be strange. In fact this difference between 

 the Araucarineae and the other three tribes only emphasizes other 

 differences that indicate the long separation of the Araucarineae from 

 the other Pinaceae. 



The scales or bracts, whatever may be their morphological charac- 

 ter, bear a variable number of ovules. Among the Abietineae the 

 number is definitely two, and the ovules are inverted; but in the 

 other tribes of Pinaceae the number is variable. Among the Taxo- 

 dineae the numbers range from two in Taxodiiim to seven to nine in 

 Sciadopitys (arranged in a transverse row), and the ovules are all 

 erect except in Cunninghamia, Sciadopitys, and sometimes Arthro- 

 iaxis. Among the Cupressineae the ovules are all erect, and range 

 in number from one or two in Juniperus and Actinostrohus to indefi- 

 nite and often numerous in Cupressus and Callitris. Among the 

 Araucarineae the solitary (sometimes two in Agathis) ovule is inverted. 



One of the remarkable features of the development of the ovule 

 of Pinaceae is the long period that often elapses between the first 

 appearance of the ovulate strobilus and the maturing and shedding 

 of the seed (fig. 274). The schedule for Piniis Laricio growing in 

 Chicago is as follows. The strobilus begins to develop in the late 

 fall and winter; in the spring the integument and nucellus of the 

 young ovule are distinct, but there is no evident differentiation of 

 sporogenous tissue; in May the mother cell is recognizable by its 

 great increase in size (the stage found in the youngest evident cones) ; 

 in October the endosperm is found as a parietal layer of free nuclei, 

 in which condition the second winter is passed; in the following 

 spring the endosperm begins to develop rapidly; and in June the 

 archegonia are ready for fertilization, which takes place about the first 

 of July, at least twenty-one months after the first organization of the 

 ovule; in the following year the seed is shed, three winters being 

 included between the primordium of the ovulate strobilus and the 

 shedding of its seed. It is recognized that this schedule is an unusually 

 long one, and how far it applies among Pinaceae is unknown. In 



