CONIFERALES 



279 



nate cones at the base and ovulate cones at the top, while the part 

 of the branch between bore both kinds of cones and also bisporan- 

 giate cones. The latter had staminate sporophylls at the base, ovu- 

 late sporophylls at the top, with sporophylls (bracts) between bear- 

 ing neither kind of sporangia. 



In most bisporangiate cones the ovulate sporophylls are at the top 

 with the staminate below; but cases have been reported in which the 

 arrangement was just the opposite. 



Fig. 282. — Picea excelsa: A, sections of microsporangia from lower part of a stro- 

 bllus like those shown in fig. 281; B, section of a pollen grain which seems to be normal. 

 The material was merely wrapped in paper and sent from a considerable distance; hence 

 the shrunken protoplasm. A, X20; B, X300. 



An abnormal cone of Pinus sp. was once sent to our laboratory as 

 a curiosity. On one side, from the bottom to the top, it looked like a 

 normal cone ; while the other side bore spur shoots with two some- 

 what stunted needles. 



Pines have been noted in which some of the ovulate structures of 

 the cone were replaced by spurs with two needles. 



Admixtures of male and female characters occur even in dioecious 

 angiosperms. In Salix petiolaris^"^ the staminate sporophyll may be 

 tipped with a stigma, and carpels, bearing ovules near their bases, 

 may bear microsporangia higher up; and still higher up, may be 

 tipped with good stigmas. 



