144 



DISPERSION OF POLLEN BY THE WIND. 



anthers borne by these filaments are broad and for the most part heart-shaped; the 

 two lobes of which each anther is composed only open on the side turned to the sky, 



Fig. 233. Mountain Pine (Pinus Pumilio). 



i A single polHniferous scale (stamen) seen from above. 2 Three polliniferous scales, one above the other, seen from the side. 

 The pollen falling from each anther alights on the upper surface of the stamen next below. 3 Two spikes of polliniferous 

 scales. * Branch with apical group of staminal flowers from which pollen is being discharged. * Female flower. ', 2 xlO; 

 8 x 8 ; * x 2 ; * natural size. 



so that the small gaping slit through which the pollen has to be discharged into the 

 air faces upward. Consistently with this fact we find that in Plantains it takes 

 a couple of days to disperse all the pollen. The same category includes the Elms 



