HORNBEAM, HAZEL, BIRCH AND ALDER 



113 



They inhabit swamps, river bottoms and moist valleys and fog belts 

 of high mountains, often forming conspicuous thickets on mountain 

 slopes. 



The leaves are relatively large, in general somewhat coarse in 

 appearance, dark green in color and shed green or very tardily 

 taking on autumnal tints. They are straight veined and with 

 toothed margins. The pollen bearing catkins are pendulous form- 



FlG. 



23. Sketch Map Showing Existing Range and Fossil Occurrences 

 Beyond that Area of the Alder 



ing the preceding season and discharging in early spring before the 

 leaves unfold, -quantities of golden yellow pollen which is carried 

 by the wind to the female flowers. The latter develop into woody 

 cones, which when preserved as fossils, simulate sequoia cones and 

 have, more than once, been mistaken for them. The seeds, really 

 nutlets, are in some of the forms winged and distributed by the 

 wind, in others they are wingless and distributed by streams. 



