The Struggle for Life in the Swamp. 25 1 
advantage of trees and shrubs for ages, one of them has 
gone to the water and done very well. This is the 
Ipomcea acetosifolia. Having developed a hollow stem 
and given up its twining habit, it now runs over the 
water to great distances, taking advantage of the floating 
plants for support. That it is not a water plant may be 
easily seen, as neither leaves nor flowers float but are 
raised well above the surface. As it does not overshadow 
the water to any very great extent, however, it is not 
such a pest to other plants as some of its cousins. 
But of all developments in water plants perhaps the 
most curious is Neptunia oleracea. Belonging to the 
family of sensitive mimosas it looks one of the least 
likely to belong to the swamp. Yet it has developed a 
spongy stem which runs along the surface of the water 
and enables it to cover large areas with its delicate 
leaves and yellow flower-balls. As in the case of the 
convolvulus neither leaves nor flowers touch the water, 
but the wavy stems like whip snakes lying on the surface 
support these easily. 
Anything like the fringe of willow herbs and loose- 
strifes which decorate the banks of English rivers, is 
entirely wanting in Guiana. Here bushes come down 
to the shore and extend into the water, leaving no room 
for smaller plants, while in the savannahs there is no 
line of demarcation between river and swamp. Another 
class of plants like the arrow-heads and water plantains 
of Europe is but sparsely represented here by a few 
Sagittarias and Crinums, The bulrush appears to 
be naturalised on the coast, flourishing in brackish pools 
and in the trenches alongside the Demerara Railway. 
In the last places their cylindrical masses of flowers and 
