CONIFERALES (PINACEAE) 



239 



two sets of sporophylls to one another is that found in the strobilus 

 of Bennettitales, in the so-called "flower" of Welwitschia, and in the 



Fig. 261. — Bisporangiate strobili of Abies: the staminate strobilus at the lower 

 right corner is almost normal; all the others have microsporangia both above and 

 below, with ovuliferous scales between. 



angiosperm flower. It is to be expected that other cases of bi- 

 sporangiate strobili will be reported, but they are evidently of very 

 rare occurrence among Pinaceae. 



Fig. 262.— Microsporangia from the strobili shown in fig. 261: A, normal sporo- 

 phyll, side view; B, slightly modified sporophyll from the summit of a bisporangiate 

 strobilus; C, D, side and front views of sporophylls from the summit of a bisporan- 

 giate strobilus; E, F, side and front views of sporophylls from the base of a bisporan- 

 giate strobilus. 



