Flora of the Galapagos Islands. 
THE FLORA OF THE GALAPAGOS ISLANDS. 
135 
I N a recent number of the Proceedings of the American Academy 
(vol. xxxviii.pp. 77-269), Dr. B. L. Robinson gives an account of 
the flora of these islands. He has brought together all the available 
material and his memoir represents the extent of our knowledge of 
the origin and distribution of plant-life on the five larger and twelve 
of the smaller islands. Our knowledge of the latter is largely owed 
to the recent expedition of Messrs. Snodgrass and Heller. The 
collections include some fungi and algae which have been worked 
out by Professor Farlow, and among which are a new lichen and 
three new seaweeds, one, Herpophyllon , a new red seaweed of 
doubtful affinity. There are also a few bryophytes and 59 pterido- 
pliytes. Three out of the 55 ferns are endemic, that is about 5 per 
cent. The total number of seed-plants (including a few introduced 
species) is 531, made up of 445 species, 17 varieties, 19 forms, and 
50 indeterminate; of these 202 species, 15 varieties and 19 forms 
are endemic, making 44*4 per cent, of the whole flowering flora. 
More than half (130) of these endemic plants are confined to a single 
island. There are only two endemic genera, both of the order 
Compositae, Lecocarpus which is monotypic, and Scalesia with 18 
species. 
As with most insular floras, the vegetation of these islands is 
striking rather by the absence of certain great groups than by the 
number and diversity of the genera and families represented. Thus 
among pteridophytes arborescent forms on the one hand and the 
filmy ferns on the other are wanting. There are no gymnosperms, 
and if we except the grasses and sedges which are well represented, 
there are very few monocotyledons. Of dicotyledons, the families 
best represented are Amarantaceae, Nyctagineae, Aizoaceae, Legum- 
inosae (about 10 per cent, of the seed-plants), Euphorbiaceae 
(about 12 per cent.), Malvaceae, Cactaceae, Convolvulaceae, 
Boraginaceae, Verbenaceae, Labiatae, Solanaceae, Rubiaceae, 
and Compositae (about 13*5 per cent.) Several great families, 
widely distributed and abundant in the tropics of continental 
America, such as Sapindaceae, Myrtaceae, Melastomaceae, Lyth- 
raceae, and Onagraceae, are scarcely or not at all represented in the 
flora of the archipelago. Altogether 72 families of vascular plants, 
including 232 genera, are known from these islands, 39 of the 
families include endemic forms. 
The orders richest in endemic species are Compositae with 39, 
Amarantaceae with 29, Euphorbiaceae with 25, Rubiaceae with 
16, Gramineae with 13, and Boraginaceae with 12, Leguminosae; 
Cactaceae and Convolvulaceae contain 6 to 8, and 29 other orders 
contain 1 to 5 endemic species. 
The lower slopes of all the islands are relatively sterile, arid 
and rough, much of the surface being covered with lava-blocks. 
The air although not excessively hot is very dry, and the predomi¬ 
nating perennial vegtation is of a small-leaved xerophytic type, 
composed of scattered shrubs and undershrubs, or wiry herbs and 
grasses, above which rise arborescent species of Cactus and Opuntia. 
On the higher islands which rise into moister air.strata, a much more 
luxuriant mesophyte vegetation prevails. Trees, if we except the 
arborescent cacti, occur chiefly upon the upper parts of the islands 
