FLOWERS POLLINATED BY THE WIND 



of pollen-grains in such immense numbers that they tinge the 

 ground yellow in places has given rise to the reports of sulphur- 

 showers. In pine-forests the air is filled with pollen, which 

 slowly settles downward, powdering the foliage and branches 

 of the trees, the grass, and the ground. The wide dissemina- 



FiG. 19. Balsam-Fir. Abies balsamea 

 Ovulate cones. A wind-pollinated conifer 



tion of pine-pollen is favored by two bladder-like wings, which 

 greatly increases its buoyancy. Where everything is covered 

 with pollen it cannot fail to come directly in contact with the 

 ends of the ovules, in each of which there is a small orifice, the 

 micropyle, or little gate. This opening is filled with a drop of 

 mucilaginous liquid, well shown in the yew and running juniper, 

 to which the pollen adheres and is subsequently drawn into the 

 ovule by its reabsorption. Coniferous pollen is not attractive 



45 



