316 Wisconsin Academy of Sciences, Arts, and Letters. 
of Cryptocarpus bushes also occur here covered with Passiflora 
foetida. Occasional trees of Hippomane Mancinella also grow 
on this area. In many places along the west and south sides of 
the bay the growth consists of low bushes, with a considerable 
number of Cereus sclerocarpus and Opuntia myriacantha trees 
scattered among them. 
After leaving the immediate vicinity of the shore, at the north 
end of the bay, one encounters dense jungles of xerophytic 
plants which extend inland a mile or more to the base of the 
cliffs mentioned above. This jungle is composed largely of trees 
of Acacia macracantha, Bursera graveolens, Erythrina velutina, 
Opuntia myriacantha, and Piscidia Erythrina. The specimens 
of Opuntia are very large, some of them attaining a height of 
thirty or more feet. In general it may be said, that nearly all 
of the species which occur in this area either attain a larger size, 
or grow more abundantly than they usually do so near to sea 
level. There is a dense growth of bushes underneath the trees 
consisting of Cordia lutea, Croton Scouleri varieties, brevifolius 
and Macraei, Discaria pauciflora, Gossypium barbadense, Lan- 
tana peduncularis, Maytenus obovata, Parkinsonia aculeata, 
Prosopis dulcis, Scalesia gummifera, Telanthera echinocephala, 
Tournefortia pubescens, and Zanthoxylum Fagara. Such ferns 
as Polypodium squamatum and Trachypteris pinnata grow on 
the sides of the cliffs at an elevation of 75 ft. Above these cliffs 
there is a considerable area which is covered with Prosopis and 
other bushes of an xerophytic character, but the arrangement of 
these is more open than below the cliffs. The trees of Opuntia 
myriacantha are numerous and very large in this area, and form 
a portion of the continuous zone of Opuntia trees which extend 
around the south side of the island. They are so numerous here 
that their redish-brown trunks give this color to the surrounding 
landscape when seen from a distance. 
There is a general thickening up of the vegetation further in¬ 
land, but there is not much change in the species of plants pres¬ 
ent below 350 ft. Around this elevation such forms as Cordia 
lutea, Croton Scouleri var. brevifolius, Discaria pauciflora, 
Opuntia myriacantha, Parkinsonia aculeata, Piscidia Erythrina, 
Prosopis dulcis, and Telanthera echinocephala disappear. The 
most of the vegetation, around this elevation, is heavily covered 
with fruticose lichens. There are dense forests here made up 
largely of trees of Pisonia floribunda, Scalesia pedunculata, and 
