Lycopodiace^: of Guiana and their Allies. 59 
very numerous microspores ; the smaller ovoid, containing a solitary 
macrospore. 
The members of this genus also are communal in 
habit, and form a sheet over water, often quite con- 
cealing the surface. They are exquisite little plants in 
stru6lure and colour, with minute imbricating leaves, 
varying from green to dark purple in colour, branched 
in the form of little prostrate trees. The species are about 
half-a-dozen, tropical and sub-tropical, found in America, 
Asia, Africa and Australia. 
# Azolla caroliniana, Willd., Baker Jour. Bot. vol. 24, p. 100, — 
Entire plant -J-f in. each way, deltoid or flabellate in outline, pinnate 
or bipinnate, obtuse, lower branches longest, the lowest shortly 
branched again at the ends. Leaves all united at the axis, biserial on 
each side, those of the Upper series larger, more fleshy, brighter 
coloured, more erect and less appressed, subovate, i-f li. 1. less broad ; 
those of the under side gray, appressed one on the other. 
Very abundant through the coast region, covering the 
surface of trenches and all still waters, on which, like 
Salvinia, it is an expensive subje6l for estates to keep 
down. The colour varies from light green to dark purple, 
but there seem to be two varieties — green shading to pink, 
and pink shading to deep purple, the former being larger 
in both plant and leaves. My specimens are not in fruit 
and I can obtain none in fruit as I write. 
General distribution — Southern United States to 
South Brasil. 
H2 
