86 

 Beach, conditions extreme in every respect ; on dn-ies, sarae 

 conditions, and also tliose of denudation and Imrial. Ajiii.opliila 

 indirectly one of tlie raost commercial plants xa the world beint' a 

 sand-'binder. \¥lien a dime gets very large, the conditioias "oecoriie 

 very bad for Aradophila and the plant dying, the wind lias fxill iJover 

 over the sand hill. After AmmophilH coraes the shnib Tioae , P:>ni::!is 

 maritanus, Ilyrica cerifera, Rlius toxicendendron. 



Tree Zone follows the shrub. Juniperus virciniana; then ydnes 

 and oaks. Oiiercus nigre seems almost as resistant as the pine. 

 A characteristic undergrowth acjsompanies each kind of tree. 

 Hurais is bein^r increased. Xerophytic beach easily told frou desert 

 Stretch while on hydrophytic beach the vegetation presents an 

 unbroken series. 

 Yfiiy is this difference ? 



1. Difference from expos\ire (seen on Spit). 



2. Difference iii Slope, that of Herophytic being more rapid than 

 hydrophytic. 



3. Hydrophytic beach more coiiimon where springs enter. 



Exposure the predominaiat factor. Shingle or gravel beaches 

 xerophytic since there is little -chance for accumulation of hunis. 

 B. Away f rorii w:a:La2l Jr9V9J-t 



1. Drained swamps or rivers. 



2. Undrained swamps or kettle holes. 



3. Hydrophytic shores or salt marsh. 



