198 BOTANICAL GAZETTE [Marci 
siveness there found, will lie. Figs. 9, 13, 14, and 75 give some 
conception of the striking features presented by a landscape of — 
which an advancing dune forms a part. Nowhere can there be — 
a sharper line in nature, nowhere a more abrupt transition. The 
height of these slopes above the country on which they at — 
advancing varies from almost nothing up to thirty meters 
Dune Park. The Glen Haven dunes are far more imposing, since 
there is an almost unbroken line of advance for four kilomet 
while the average height is from thirty to sixty meters above 
the territory on which they are encroaching. ) 
The vegetation of the complex proper is exceedingly spats? 
In the winter it appears almost a barren waste. The one plant 
which seems to be at home in all locations, whether wind-sweeps 
exposed summits, or protected lees, is the bugseed, Corispermut 
hyssopifolium. This plant is an annual, and has been previously 
mentioned as a tenant of the beach and the beach dunes. iE 
bugseed is shown in several of the photographs, but best i | 
left foreground of fig. 12. The seeds are winged and read! 
dispersed by the wind. Furthermore they germinate 1a 
during wet spring weather. This power of rapid germinal ie 
a necessary condition of success, since the surface layers of sand 
dry off very quickly after the wet weather has ceased. The platt® 
are obliged not only to germinate rapidly but also to send roots 
deep enough to reach beyond the surface desiccation. Evea 
this perfectly successful plant species is often absent from large 
areas on the dune-complex, probably because of the difficull : 
which the seeds meet in finding lodgment. It is only a” eee 
tional seed which is allowed to remain stranded on the comps’ 
and many of the seeds which succeed in finding lodgment 
likely to be buried too far below the surface to permit er 
nation, ae 
Another plant which deserves especial mention is the i 
Wood, Populus monilifera. The plasticity of this species 5". 
able. Normally at home along protected river bette 
yet able to endure almost all of the severe conditions ° as 
dune-complex. Mention has been made of its importance °” 
