Stewart—Botanical Conditions ,on the Galapagos Islands. 275 
growing in this region, less abundantly than the above are: Cor- 
dia lutea, Castela galapageia, Croton Scouleri var. brevifolius, 
Euphorbia articulata, Prosopis dulcis, Scalesia Hopkinsii, Tel- 
anthera echinoeephala, and Waltheria reticulata. The lava 
ridges are often found to be more or less covered with vines 
of Ipomoea Habeliana, and in various other places on t the 
lava, I. Kinbergi was found growing and in blossom at the time 
of our visit. Such grasses as Aristida suspicata, Cenchrus platy- 
acanthus, Leptochloa albemarlensis and L. Lindleyana grew 
with more or less abundance in the lava crevices. On the older 
beds of volcanic cinders there was very little vegetation other 
than occasional bunches of Cereus nesioticus; the more recent 
beds of cinders were bare. 
A change, readily noticed, takes place in the vegetation at 
about 450 ft. elevation evidently brought about by the greater 
amount of moisture and a more abundant soil. There is a gen¬ 
eral thickening up and an increase in the size of the vegetation 
above this elevation. There are good sized trees of Bursera 
graveolens in this region, and also trees of Pisonia floribunda, 
which first make their appearance. Many of the trees and 
bushes, at this elevation and above, are heavily covered with 
Alectoria sarmentosa and other epiphytic lichens. Bushes and 
small trees of Zanthoxylum Fagara also occur, usually infested 
with Phoradendron Ilenslovii. Other bushes which occur in this 
region and a little higher are: Chiococca alba, Erigeron tenui- 
folius, Lipochaeta laricifolia, and Lippia rosmarinifolia. Such 
ferns as Chelianthes microphylla, and Polypodium squamatum 
occur. Very little change takes place in the vegetation on the 
southwest side of the island below an elevation of 700 ft., prob¬ 
ably due to the fact that this side receives less moisture than the. 
south and southeast sides. 
Practically all of the plants which occur below 500 ft. dis¬ 
appear by the time an elevation of 1,000 ft. is reached. The spe¬ 
cies that continue into this region from below, are, for the most 
part, those which first appeared around an elevation of 500 ft, 
and above. The region between 1,000 and 1,650 ft. elevation is 
covered with forests, on the southeast side, which are made up 
mostly of Pisonia floribunda, and Zanthoxylum Fagara. There 
is much undergrowth in these forests, consisting of bushes of 
Croton Scouleri var. grandifolius, Erigeron tenuifolius, Lippia 
rosmarinifolia, Psychotria rufipes, Scalesia Hopkinsii, Tounie- 
